Merge tag 'mm-nonmm-stable-2022-08-06-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc updates from Andrew Morton:
"Updates to various subsystems which I help look after. lib, ocfs2,
fatfs, autofs, squashfs, procfs, etc. A relatively small amount of
material this time"

* tag 'mm-nonmm-stable-2022-08-06-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits)
scripts/gdb: ensure the absolute path is generated on initial source
MAINTAINERS: kunit: add David Gow as a maintainer of KUnit
mailmap: add linux.dev alias for Brendan Higgins
mailmap: update Kirill's email
profile: setup_profiling_timer() is moslty not implemented
ocfs2: fix a typo in a comment
ocfs2: use the bitmap API to simplify code
ocfs2: remove some useless functions
lib/mpi: fix typo 'the the' in comment
proc: add some (hopefully) insightful comments
bdi: remove enum wb_congested_state
kernel/hung_task: fix address space of proc_dohung_task_timeout_secs
lib/lzo/lzo1x_compress.c: replace ternary operator with min() and min_t()
squashfs: support reading fragments in readahead call
squashfs: implement readahead
squashfs: always build "file direct" version of page actor
Revert "squashfs: provide backing_dev_info in order to disable read-ahead"
fs/ocfs2: Fix spelling typo in comment
ia64: old_rr4 added under CONFIG_HUGETLB_PAGE
proc: fix test for "vsyscall=xonly" boot option
...

.mailmap

···
 Boris Brezillon <[e-mail]> <[e-mail]>
 Boris Brezillon <[e-mail]> <[e-mail]>
 Boris Brezillon <[e-mail]> <[e-mail]>
+Brendan Higgins <[e-mail]> <[e-mail]>
 Brian Avery <[e-mail]>
 Brian King <[e-mail]>
 Brian Silverman <[e-mail]> <[e-mail]>
···
 Keith Busch <[e-mail]> <[e-mail]>
 Keith Busch <[e-mail]> <[e-mail]>
 Kenneth W Chen <[e-mail]>
-Kirill Tkhai <[e-mail]> <[e-mail]>
+Kirill Tkhai <[e-mail]> <[e-mail]>
 Konstantin Khlebnikov <[e-mail]> <[e-mail]>
 Konstantin Khlebnikov <[e-mail]> <[e-mail]>
 Koushik <[e-mail]>

Documentation/admin-guide/kernel-parameters.txt

···
 
 	hlt		[BUGS=ARM,SH]
 
+	hostname=	[KNL] Set the hostname (aka UTS nodename).
+			Format: <string>
+			This allows setting the system's hostname during early
+			startup. This sets the name returned by gethostname.
+			Using this parameter to set the hostname makes it
+			possible to ensure the hostname is correctly set before
+			any userspace processes run, avoiding the possibility
+			that a process may call gethostname before the hostname
+			has been explicitly set, resulting in the calling
+			process getting an incorrect result. The string must
+			not exceed the maximum allowed hostname length (usually
+			64 characters) and will be truncated otherwise.
+
 	hpet=		[X86-32,HPET] option to control HPET usage
 			Format: { enable (default) | disable | force |
 				verbose }

MAINTAINERS

···
 
 KERNEL UNIT TESTING FRAMEWORK (KUnit)
 M:	Brendan Higgins <[e-mail]>
+M:	David Gow <[e-mail]>
 L:	[e-mail]
 L:	[e-mail]
 S:	Maintained
···
 S:	Maintained
 F:	Documentation/filesystems/vfat.rst
 F:	fs/fat/
+F:	tools/testing/selftests/filesystems/fat/
 
 VFIO DRIVER
 M:	Alex Williamson <[e-mail]>

arch/alpha/kernel/smp.c

···
 	       ((bogosum + 2500) / (5000/HZ)) % 100);
 }
 
-int
-setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 static void
 send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation)
 {

arch/arc/kernel/smp.c

···
 	return 0;
 }
 
-/*
- * not supported here
- */
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 /*****************************************************************************/
 /*              Inter Processor Interrupt Handling                           */
 /*****************************************************************************/

arch/arm/kernel/smp.c

···
 		cpu_relax();
 }
 
-/*
- * not supported here
- */
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 #ifdef CONFIG_CPU_FREQ
 
 static DEFINE_PER_CPU(unsigned long, l_p_j_ref);

arch/arm64/kernel/smp.c

···
 }
 #endif
 
-/*
- * not supported here
- */
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 static bool have_cpu_die(void)
 {
 #ifdef CONFIG_HOTPLUG_CPU

arch/csky/kernel/smp.c

···
 {
 }
 
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 void csky_start_secondary(void)
 {
 	struct mm_struct *mm = &init_mm;

arch/hexagon/kernel/smp.c

···
 	send_ipi(mask, IPI_CALL_FUNC);
 }
 
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 void smp_start_cpus(void)
 {
 	int i;

arch/ia64/include/asm/mmu_context.h

···
 {
 	unsigned long rid;
 	unsigned long rid_incr = 0;
-	unsigned long rr0, rr1, rr2, rr3, rr4, old_rr4;
+	unsigned long rr0, rr1, rr2, rr3, rr4;
 
+#ifdef CONFIG_HUGETLB_PAGE
+	unsigned long old_rr4;
 	old_rr4 = ia64_get_rr(RGN_BASE(RGN_HPAGE));
+#endif
 	rid = context << 3;	/* make space for encoding the region number */
 	rid_incr = 1 << 8;
 

arch/ia64/include/uapi/asm/cmpxchg.h

···
 									\
 	switch (size) {							\
 	case 1:								\
-		__xchg_result = ia64_xchg1((__u8 *)ptr, x);		\
+		__xchg_result = ia64_xchg1((__u8 __force *)ptr, x);	\
 		break;							\
 									\
 	case 2:								\
-		__xchg_result = ia64_xchg2((__u16 *)ptr, x);		\
+		__xchg_result = ia64_xchg2((__u16 __force *)ptr, x);	\
 		break;							\
 									\
 	case 4:								\
-		__xchg_result = ia64_xchg4((__u32 *)ptr, x);		\
+		__xchg_result = ia64_xchg4((__u32 __force *)ptr, x);	\
 		break;							\
 									\
 	case 8:								\
-		__xchg_result = ia64_xchg8((__u64 *)ptr, x);		\
+		__xchg_result = ia64_xchg8((__u64 __force *)ptr, x);	\
 		break;							\
 	default:							\
 		ia64_xchg_called_with_bad_pointer();			\
 	}								\
-	__xchg_result;							\
+	(__typeof__ (*(ptr)) __force) __xchg_result;			\
 })
 
 #ifndef __KERNEL__
···
 									\
 	switch (size) {							\
 	case 1:								\
-		_o_ = (__u8) (long) (old);				\
+		_o_ = (__u8) (long __force) (old);			\
 		break;							\
 	case 2:								\
-		_o_ = (__u16) (long) (old);				\
+		_o_ = (__u16) (long __force) (old);			\
 		break;							\
 	case 4:								\
-		_o_ = (__u32) (long) (old);				\
+		_o_ = (__u32) (long __force) (old);			\
 		break;							\
 	case 8:								\
-		_o_ = (__u64) (long) (old);				\
+		_o_ = (__u64) (long __force) (old);			\
 		break;							\
 	default:							\
 		break;							\
 	}								\
 	switch (size) {							\
 	case 1:								\
-		_r_ = ia64_cmpxchg1_##sem((__u8 *) ptr, new, _o_);	\
+		_r_ = ia64_cmpxchg1_##sem((__u8 __force *) ptr, new, _o_);	\
 		break;							\
 									\
 	case 2:								\
-		_r_ = ia64_cmpxchg2_##sem((__u16 *) ptr, new, _o_);	\
+		_r_ = ia64_cmpxchg2_##sem((__u16 __force *) ptr, new, _o_);	\
 		break;							\
 									\
 	case 4:								\
-		_r_ = ia64_cmpxchg4_##sem((__u32 *) ptr, new, _o_);	\
+		_r_ = ia64_cmpxchg4_##sem((__u32 __force *) ptr, new, _o_);	\
 		break;							\
 									\
 	case 8:								\
-		_r_ = ia64_cmpxchg8_##sem((__u64 *) ptr, new, _o_);	\
+		_r_ = ia64_cmpxchg8_##sem((__u64 __force *) ptr, new, _o_);	\
 		break;							\
 									\
 	default:							\
 		_r_ = ia64_cmpxchg_called_with_bad_pointer();		\
 		break;							\
 	}								\
-	(__typeof__(old)) _r_;						\
+	(__typeof__(old) __force) _r_;					\
 })
 
 #define cmpxchg_acq(ptr, o, n)	\

arch/ia64/kernel/smp.c

···
 {
 	send_IPI_allbutself(IPI_CPU_STOP);
 }
-
-int
-setup_profiling_timer (unsigned int multiplier)
-{
-	return -EINVAL;
-}

arch/openrisc/kernel/smp.c

···
 	smp_call_function(stop_this_cpu, NULL, 0);
 }
 
-/* not supported, yet */
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
 {
 	smp_cross_call = fn;

arch/parisc/kernel/smp.c

···
 
 	pdc_cpu_rendezvous_unlock();
 }
-
-#ifdef CONFIG_PROC_FS
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-#endif

arch/powerpc/kernel/smp.c

···
 	BUG();
 }
 
-#ifdef CONFIG_PROFILING
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return 0;
-}
-#endif
-
 static void __init fixup_topology(void)
 {
 	int i;

arch/riscv/kernel/smp.c

···
 	return phys_id == cpuid_to_hartid_map(cpu);
 }
 
-/* Unsupported */
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 static void ipi_stop(void)
 {
 	set_cpu_online(smp_processor_id(), false);

arch/sparc/kernel/smp_32.c

···
 	irq_exit();
 }
 
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
 	int i, cpuid, extra;

arch/sparc/kernel/smp_64.c

···
 	preempt_enable();
 }
 
-/* /proc/profile writes can call this, don't __init it please. */
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
 }

arch/x86/include/asm/apic.h

···
 #include <asm/paravirt.h>
 #endif
 
-extern int setup_profiling_timer(unsigned int);
-
 static inline void native_apic_mem_write(u32 reg, u32 v)
 {
 	volatile u32 *addr = (volatile u32 *)(APIC_BASE + reg);

arch/x86/kernel/apic/apic.c

···
 	set_irq_regs(old_regs);
 }
 
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 /*
  * Local APIC start and shutdown
  */

arch/x86/kernel/cpu/cacheinfo.c

···
 #define LVL_3		4
 #define LVL_TRACE	5
 
+/* Shared last level cache maps */
+DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
+
+/* Shared L2 cache maps */
+DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_l2c_shared_map);
+
 struct _cache_table {
 	unsigned char descriptor;
 	char cache_type;

arch/x86/kernel/smpboot.c

···
 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_die_map);
 EXPORT_PER_CPU_SYMBOL(cpu_die_map);
 
-DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
-
-DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_l2c_shared_map);
-
 /* Per CPU bogomips and other parameters */
 DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
 EXPORT_PER_CPU_SYMBOL(cpu_info);

fs/autofs/autofs_i.h

···
  */
 struct autofs_info {
 	struct dentry	*dentry;
-	struct inode	*inode;
-
 	int		flags;
 
 	struct completion expire_complete;
···
 {
 	return ((sbi->flags & AUTOFS_SBI_CATATONIC) ||
 		 task_pgrp(current) == sbi->oz_pgrp);
+}
+
+static inline bool autofs_empty(struct autofs_info *ino)
+{
+	return ino->count < 2;
 }
 
 struct inode *autofs_get_inode(struct super_block *, umode_t);

fs/autofs/expire.c

···
 		return NULL;
 	}
 
-	if (simple_empty(dentry))
+	if (autofs_empty(ino))
 		return NULL;
 
 	/* Case 2: tree mount, expire iff entire tree is not busy */

fs/autofs/inode.c

···
 		INIT_LIST_HEAD(&ino->expiring);
 		ino->last_used = jiffies;
 		ino->sbi = sbi;
+		ino->count = 1;
 	}
 	return ino;
 }

fs/autofs/root.c

···
 
 #include "autofs_i.h"
 
+static int autofs_dir_permission(struct user_namespace *, struct inode *, int);
 static int autofs_dir_symlink(struct user_namespace *, struct inode *,
 			      struct dentry *, const char *);
 static int autofs_dir_unlink(struct inode *, struct dentry *);
···
 
 const struct inode_operations autofs_dir_inode_operations = {
 	.lookup		= autofs_lookup,
+	.permission	= autofs_dir_permission,
 	.unlink		= autofs_dir_unlink,
 	.symlink	= autofs_dir_symlink,
 	.mkdir		= autofs_dir_mkdir,
···
 {
 	struct dentry *dentry = file->f_path.dentry;
 	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
 
 	pr_debug("file=%p dentry=%p %pd\n", file, dentry, dentry);
 
···
 	 * it.
 	 */
 	spin_lock(&sbi->lookup_lock);
-	if (!path_is_mountpoint(&file->f_path) && simple_empty(dentry)) {
+	if (!path_is_mountpoint(&file->f_path) && autofs_empty(ino)) {
 		spin_unlock(&sbi->lookup_lock);
 		return -ENOENT;
 	}
···
 	struct dentry *dentry = path->dentry;
 	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
 
-	/*
-	 * If this is an indirect mount the dentry could have gone away
-	 * as a result of an expire and a new one created.
+	/* If this is an indirect mount the dentry could have gone away
+	 * and a new one created.
+	 *
+	 * This is unusual and I can't remember the case for which it
+	 * was originally added now. But an example of how this can
+	 * happen is an autofs indirect mount that has the "browse"
+	 * option set and also has the "symlink" option in the autofs
+	 * map entry. In this case the daemon will remove the browse
+	 * directory and create a symlink as the mount leaving the
+	 * struct path stale.
+	 *
+	 * Another not so obvious case is when a mount in an autofs
+	 * indirect mount that uses the "nobrowse" option is being
+	 * expired at the same time as a path walk. If the mount has
+	 * been umounted but the mount point directory seen before
+	 * becoming unhashed (during a lockless path walk) when a stat
+	 * family system call is made the mount won't be re-mounted as
+	 * it should. In this case the mount point that's been removed
+	 * (by the daemon) will be stale and the a new mount point
+	 * dentry created.
 	 */
 	if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) {
 		struct dentry *parent = dentry->d_parent;
···
 		 * the mount never trigger mounts themselves (they have an
 		 * autofs trigger mount mounted on them). But v4 pseudo direct
 		 * mounts do need the leaves to trigger mounts. In this case
-		 * we have no choice but to use the list_empty() check and
+		 * we have no choice but to use the autofs_empty() check and
 		 * require user space behave.
 		 */
 		if (sbi->version > 4) {
···
 				goto done;
 			}
 		} else {
-			if (!simple_empty(dentry)) {
+			if (!autofs_empty(ino)) {
 				spin_unlock(&sbi->fs_lock);
 				goto done;
 			}
···
 
 	if (rcu_walk) {
 		/* We don't need fs_lock in rcu_walk mode,
-		 * just testing 'AUTOFS_INFO_NO_RCU' is enough.
-		 * simple_empty() takes a spinlock, so leave it
-		 * to last.
+		 * just testing 'AUTOFS_INF_WANT_EXPIRE' is enough.
+		 *
 		 * We only return -EISDIR when certain this isn't
 		 * a mount-trap.
 		 */
···
 		inode = d_inode_rcu(dentry);
 		if (inode && S_ISLNK(inode->i_mode))
 			return -EISDIR;
-		if (list_empty(&dentry->d_subdirs))
-			return 0;
-		if (!simple_empty(dentry))
+		if (!autofs_empty(ino))
 			return -EISDIR;
 		return 0;
 	}
···
 		 * we can avoid needless calls ->d_automount() and avoid
 		 * an incorrect ELOOP error return.
 		 */
-		if ((!path_is_mountpoint(path) && !simple_empty(dentry)) ||
+		if ((!path_is_mountpoint(path) && !autofs_empty(ino)) ||
 		    (d_really_is_positive(dentry) && d_is_symlink(dentry)))
 			status = -EISDIR;
 	}
···
 	return NULL;
 }
 
+static int autofs_dir_permission(struct user_namespace *mnt_userns,
+				 struct inode *inode, int mask)
+{
+	if (mask & MAY_WRITE) {
+		struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
+
+		if (!autofs_oz_mode(sbi))
+			return -EACCES;
+
+		/* autofs_oz_mode() needs to allow path walks when the
+		 * autofs mount is catatonic but the state of an autofs
+		 * file system needs to be preserved over restarts.
+		 */
+		if (sbi->flags & AUTOFS_SBI_CATATONIC)
+			return -EACCES;
+	}
+
+	return generic_permission(mnt_userns, inode, mask);
+}
+
 static int autofs_dir_symlink(struct user_namespace *mnt_userns,
 			      struct inode *dir, struct dentry *dentry,
 			      const char *symname)
 {
-	struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
 	struct autofs_info *ino = autofs_dentry_ino(dentry);
 	struct autofs_info *p_ino;
 	struct inode *inode;
···
 	char *cp;
 
 	pr_debug("%s <- %pd\n", symname, dentry);
-
-	if (!autofs_oz_mode(sbi))
-		return -EACCES;
-
-	/* autofs_oz_mode() needs to allow path walks when the
-	 * autofs mount is catatonic but the state of an autofs
-	 * file system needs to be preserved over restarts.
-	 */
-	if (sbi->flags & AUTOFS_SBI_CATATONIC)
-		return -EACCES;
 
 	BUG_ON(!ino);
 
···
 	d_add(dentry, inode);
 
 	dget(dentry);
-	ino->count++;
 	p_ino = autofs_dentry_ino(dentry->d_parent);
 	p_ino->count++;
 
···
 	struct autofs_info *ino = autofs_dentry_ino(dentry);
 	struct autofs_info *p_ino;
 
-	if (!autofs_oz_mode(sbi))
-		return -EACCES;
-
-	/* autofs_oz_mode() needs to allow path walks when the
-	 * autofs mount is catatonic but the state of an autofs
-	 * file system needs to be preserved over restarts.
-	 */
-	if (sbi->flags & AUTOFS_SBI_CATATONIC)
-		return -EACCES;
-
-	ino->count--;
 	p_ino = autofs_dentry_ino(dentry->d_parent);
 	p_ino->count--;
 	dput(ino->dentry);
···
 
 	pr_debug("dentry %p, removing %pd\n", dentry, dentry);
 
-	if (!autofs_oz_mode(sbi))
-		return -EACCES;
-
-	/* autofs_oz_mode() needs to allow path walks when the
-	 * autofs mount is catatonic but the state of an autofs
-	 * file system needs to be preserved over restarts.
-	 */
-	if (sbi->flags & AUTOFS_SBI_CATATONIC)
-		return -EACCES;
-
 	if (ino->count != 1)
 		return -ENOTEMPTY;
 
···
 	if (sbi->version < 5)
 		autofs_clear_leaf_automount_flags(dentry);
 
-	ino->count--;
 	p_ino = autofs_dentry_ino(dentry->d_parent);
 	p_ino->count--;
 	dput(ino->dentry);
···
 	struct autofs_info *p_ino;
 	struct inode *inode;
 
-	if (!autofs_oz_mode(sbi))
-		return -EACCES;
-
-	/* autofs_oz_mode() needs to allow path walks when the
-	 * autofs mount is catatonic but the state of an autofs
-	 * file system needs to be preserved over restarts.
-	 */
-	if (sbi->flags & AUTOFS_SBI_CATATONIC)
-		return -EACCES;
-
 	pr_debug("dentry %p, creating %pd\n", dentry, dentry);
 
 	BUG_ON(!ino);
···
 		autofs_set_leaf_automount_flags(dentry);
 
 	dget(dentry);
-	ino->count++;
 	p_ino = autofs_dentry_ino(dentry->d_parent);
 	p_ino->count++;
 	inc_nlink(dir);

fs/eventpoll.c

···
 	return to;
 }
 
+/*
+ * autoremove_wake_function, but remove even on failure to wake up, because we
+ * know that default_wake_function/ttwu will only fail if the thread is already
+ * woken, and in that case the ep_poll loop will remove the entry anyways, not
+ * try to reuse it.
+ */
+static int ep_autoremove_wake_function(struct wait_queue_entry *wq_entry,
+				       unsigned int mode, int sync, void *key)
+{
+	int ret = default_wake_function(wq_entry, mode, sync, key);
+
+	list_del_init(&wq_entry->entry);
+	return ret;
+}
+
 /**
  * ep_poll - Retrieves ready events, and delivers them to the caller-supplied
  *           event buffer.
···
 		 * normal wakeup path no need to call __remove_wait_queue()
 		 * explicitly, thus ep->lock is not taken, which halts the
 		 * event delivery.
+		 *
+		 * In fact, we now use an even more aggressive function that
+		 * unconditionally removes, because we don't reuse the wait
+		 * entry between loop iterations. This lets us also avoid the
+		 * performance issue if a process is killed, causing all of its
+		 * threads to wake up without being removed normally.
 		 */
 		init_wait(&wait);
+		wait.func = ep_autoremove_wake_function;
 
 		write_lock_irq(&ep->lock);
 		/*

fs/fat/namei_vfat.c

···
 	return err;
 }
 
-static int vfat_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
-		       struct dentry *old_dentry, struct inode *new_dir,
-		       struct dentry *new_dentry, unsigned int flags)
+static int vfat_get_dotdot_de(struct inode *inode, struct buffer_head **bh,
+			      struct msdos_dir_entry **de)
+{
+	if (S_ISDIR(inode->i_mode)) {
+		if (fat_get_dotdot_entry(inode, bh, de))
+			return -EIO;
+	}
+	return 0;
+}
+
+static int vfat_sync_ipos(struct inode *dir, struct inode *inode)
+{
+	if (IS_DIRSYNC(dir))
+		return fat_sync_inode(inode);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+static int vfat_update_dotdot_de(struct inode *dir, struct inode *inode,
+				 struct buffer_head *dotdot_bh,
+				 struct msdos_dir_entry *dotdot_de)
+{
+	fat_set_start(dotdot_de, MSDOS_I(dir)->i_logstart);
+	mark_buffer_dirty_inode(dotdot_bh, inode);
+	if (IS_DIRSYNC(dir))
+		return sync_dirty_buffer(dotdot_bh);
+	return 0;
+}
+
+static void vfat_update_dir_metadata(struct inode *dir, struct timespec64 *ts)
+{
+	inode_inc_iversion(dir);
+	fat_truncate_time(dir, ts, S_CTIME | S_MTIME);
+	if (IS_DIRSYNC(dir))
+		(void)fat_sync_inode(dir);
+	else
+		mark_inode_dirty(dir);
+}
+
+static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
+		       struct inode *new_dir, struct dentry *new_dentry)
 {
 	struct buffer_head *dotdot_bh;
-	struct msdos_dir_entry *dotdot_de;
+	struct msdos_dir_entry *dotdot_de = NULL;
 	struct inode *old_inode, *new_inode;
 	struct fat_slot_info old_sinfo, sinfo;
 	struct timespec64 ts;
 	loff_t new_i_pos;
-	int err, is_dir, update_dotdot, corrupt = 0;
+	int err, is_dir, corrupt = 0;
 	struct super_block *sb = old_dir->i_sb;
-
-	if (flags & ~RENAME_NOREPLACE)
-		return -EINVAL;
 
 	old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
 	old_inode = d_inode(old_dentry);
···
 	if (err)
 		goto out;
 
-	is_dir = S_ISDIR(old_inode->i_mode);
-	update_dotdot = (is_dir && old_dir != new_dir);
-	if (update_dotdot) {
-		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
-			err = -EIO;
+	if (old_dir != new_dir) {
+		err = vfat_get_dotdot_de(old_inode, &dotdot_bh, &dotdot_de);
+		if (err)
 			goto out;
-		}
 	}
 
+	is_dir = S_ISDIR(old_inode->i_mode);
 	ts = current_time(old_dir);
 	if (new_inode) {
 		if (is_dir) {
···
 
 	fat_detach(old_inode);
 	fat_attach(old_inode, new_i_pos);
-	if (IS_DIRSYNC(new_dir)) {
-		err = fat_sync_inode(old_inode);
-		if (err)
-			goto error_inode;
-	} else
-		mark_inode_dirty(old_inode);
+	err = vfat_sync_ipos(new_dir, old_inode);
+	if (err)
+		goto error_inode;
 
-	if (update_dotdot) {
-		fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
-		mark_buffer_dirty_inode(dotdot_bh, old_inode);
-		if (IS_DIRSYNC(new_dir)) {
-			err = sync_dirty_buffer(dotdot_bh);
-			if (err)
-				goto error_dotdot;
-		}
+	if (dotdot_de) {
+		err = vfat_update_dotdot_de(new_dir, old_inode, dotdot_bh,
+					    dotdot_de);
+		if (err)
+			goto error_dotdot;
 		drop_nlink(old_dir);
 		if (!new_inode)
  			inc_nlink(new_dir);
···
 	old_sinfo.bh = NULL;
 	if (err)
 		goto error_dotdot;
-	inode_inc_iversion(old_dir);
-	fat_truncate_time(old_dir, &ts, S_CTIME|S_MTIME);
-	if (IS_DIRSYNC(old_dir))
-		(void)fat_sync_inode(old_dir);
-	else
-		mark_inode_dirty(old_dir);
+	vfat_update_dir_metadata(old_dir, &ts);
 
 	if (new_inode) {
 		drop_nlink(new_inode);
···
 	/* data cluster is shared, serious corruption */
 	corrupt = 1;
 
-	if (update_dotdot) {
-		fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
-		mark_buffer_dirty_inode(dotdot_bh, old_inode);
-		corrupt |= sync_dirty_buffer(dotdot_bh);
+	if (dotdot_de) {
+		corrupt |= vfat_update_dotdot_de(old_dir, old_inode, dotdot_bh,
+						 dotdot_de);
 	}
 error_inode:
 	fat_detach(old_inode);
···
 	goto out;
 }
 
+static void vfat_exchange_ipos(struct inode *old_inode, struct inode *new_inode,
+			       loff_t old_i_pos, loff_t new_i_pos)
+{
+	fat_detach(old_inode);
+	fat_detach(new_inode);
+	fat_attach(old_inode, new_i_pos);
+	fat_attach(new_inode, old_i_pos);
+}
+
+static void vfat_move_nlink(struct inode *src, struct inode *dst)
+{
+	drop_nlink(src);
+	inc_nlink(dst);
+}
+
+static int vfat_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
+				struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct buffer_head *old_dotdot_bh = NULL, *new_dotdot_bh = NULL;
+	struct msdos_dir_entry *old_dotdot_de = NULL, *new_dotdot_de = NULL;
+	struct inode *old_inode, *new_inode;
+	struct timespec64 ts = current_time(old_dir);
+	loff_t old_i_pos, new_i_pos;
+	int err, corrupt = 0;
+	struct super_block *sb = old_dir->i_sb;
+
+	old_inode = d_inode(old_dentry);
+	new_inode = d_inode(new_dentry);
+
+	/* Acquire super block lock for the operation to be atomic */
+	mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+	/* if directories are not the same, get ".." info to update */
+	if (old_dir != new_dir) {
+		err = vfat_get_dotdot_de(old_inode, &old_dotdot_bh,
+					 &old_dotdot_de);
+		if (err)
+			goto out;
+
+		err = vfat_get_dotdot_de(new_inode, &new_dotdot_bh,
+					 &new_dotdot_de);
+		if (err)
+			goto out;
+	}
+
+	old_i_pos = MSDOS_I(old_inode)->i_pos;
+	new_i_pos = MSDOS_I(new_inode)->i_pos;
+
+	vfat_exchange_ipos(old_inode, new_inode, old_i_pos, new_i_pos);
+
+	err = vfat_sync_ipos(old_dir, new_inode);
+	if (err)
+		goto error_exchange;
+	err = vfat_sync_ipos(new_dir, old_inode);
+	if (err)
+		goto error_exchange;
+
+	/* update ".." directory entry info */
+	if (old_dotdot_de) {
+		err = vfat_update_dotdot_de(new_dir, old_inode, old_dotdot_bh,
+					    old_dotdot_de);
+		if (err)
+			goto error_old_dotdot;
+	}
+	if (new_dotdot_de) {
+		err = vfat_update_dotdot_de(old_dir, new_inode, new_dotdot_bh,
+					    new_dotdot_de);
+		if (err)
+			goto error_new_dotdot;
+	}
+
+	/* if cross directory and only one is a directory, adjust nlink */
+	if (!old_dotdot_de != !new_dotdot_de) {
+		if (old_dotdot_de)
+			vfat_move_nlink(old_dir, new_dir);
+		else
+			vfat_move_nlink(new_dir, old_dir);
+	}
+
+	vfat_update_dir_metadata(old_dir, &ts);
+	/* if directories are not the same, update new_dir as well */
+	if (old_dir != new_dir)
+		vfat_update_dir_metadata(new_dir, &ts);
+
+out:
+	brelse(old_dotdot_bh);
+	brelse(new_dotdot_bh);
+	mutex_unlock(&MSDOS_SB(sb)->s_lock);
+
+	return err;
+
+error_new_dotdot:
+	if (new_dotdot_de) {
+		corrupt |= vfat_update_dotdot_de(new_dir, new_inode,
+						 new_dotdot_bh, new_dotdot_de);
+	}
+
+error_old_dotdot:
+	if (old_dotdot_de) {
+		corrupt |= vfat_update_dotdot_de(old_dir, old_inode,
+						 old_dotdot_bh, old_dotdot_de);
+	}
+
+error_exchange:
+	vfat_exchange_ipos(old_inode, new_inode, new_i_pos, old_i_pos);
+	corrupt |= vfat_sync_ipos(new_dir, new_inode);
+	corrupt |= vfat_sync_ipos(old_dir, old_inode);
+
+	if (corrupt < 0) {
+		fat_fs_error(new_dir->i_sb,
+			     "%s: Filesystem corrupted (i_pos %lld, %lld)",
+			     __func__, old_i_pos, new_i_pos);
+	}
+	goto out;
+}
+
+static int vfat_rename2(struct user_namespace *mnt_userns, struct inode *old_dir,
+			struct dentry *old_dentry, struct inode *new_dir,
+			struct dentry *new_dentry, unsigned int flags)
+{
+	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
+		return -EINVAL;
+
+	if (flags & RENAME_EXCHANGE) {
+		return vfat_rename_exchange(old_dir, old_dentry,
+					    new_dir, new_dentry);
+	}
+
+	/* VFS already handled RENAME_NOREPLACE, handle it as a normal rename */
+	return vfat_rename(old_dir, old_dentry, new_dir, new_dentry);
+}
+
 static const struct inode_operations vfat_dir_inode_operations = {
 	.create		= vfat_create,
 	.lookup		= vfat_lookup,
 	.unlink		= vfat_unlink,
 	.mkdir		= vfat_mkdir,
 	.rmdir		= vfat_rmdir,
-	.rename		= vfat_rename,
+	.rename		= vfat_rename2,
 	.setattr	= fat_setattr,
 	.getattr	= fat_getattr,
 	.update_time	= fat_update_time,

fs/kernel_read_file.c

···
  * change between calls to kernel_read_file().
  *
  * Returns number of bytes read (no single read will be bigger
- * than INT_MAX), or negative on error.
+ * than SSIZE_MAX), or negative on error.
  *
  */
-int kernel_read_file(struct file *file, loff_t offset, void **buf,
-		     size_t buf_size, size_t *file_size,
-		     enum kernel_read_file_id id)
+ssize_t kernel_read_file(struct file *file, loff_t offset, void **buf,
+			 size_t buf_size, size_t *file_size,
+			 enum kernel_read_file_id id)
 {
 	loff_t i_size, pos;
-	size_t copied;
+	ssize_t copied;
 	void *allocated = NULL;
 	bool whole_file;
 	int ret;
···
 		goto out;
 	}
 	/* The file is too big for sane activities. */
-	if (i_size > INT_MAX) {
+	if (i_size > SSIZE_MAX) {
 		ret = -EFBIG;
 		goto out;
 	}
···
 }
 EXPORT_SYMBOL_GPL(kernel_read_file);
 
-int kernel_read_file_from_path(const char *path, loff_t offset, void **buf,
-			       size_t buf_size, size_t *file_size,
-			       enum kernel_read_file_id id)
+ssize_t kernel_read_file_from_path(const char *path, loff_t offset, void **buf,
+				   size_t buf_size, size_t *file_size,
+				   enum kernel_read_file_id id)
 {
 	struct file *file;
-	int ret;
+	ssize_t ret;
 
 	if (!path || !*path)
 		return -EINVAL;
···
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
 
-int kernel_read_file_from_path_initns(const char *path, loff_t offset,
-				      void **buf, size_t buf_size,
-				      size_t *file_size,
-				      enum kernel_read_file_id id)
+ssize_t kernel_read_file_from_path_initns(const char *path, loff_t offset,
+					  void **buf, size_t buf_size,
+					  size_t *file_size,
+					  enum kernel_read_file_id id)
 {
 	struct file *file;
 	struct path root;
-	int ret;
+	ssize_t ret;
 
 	if (!path || !*path)
 		return -EINVAL;
···
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
 
-int kernel_read_file_from_fd(int fd, loff_t offset, void **buf,
-			     size_t buf_size, size_t *file_size,
-			     enum kernel_read_file_id id)
+ssize_t kernel_read_file_from_fd(int fd, loff_t offset, void **buf,
+				 size_t buf_size, size_t *file_size,
+				 enum kernel_read_file_id id)
 {
 	struct fd f = fdget(fd);
-	int ret = -EBADF;
+	ssize_t ret = -EBADF;
 
 	if (!f.file || !(f.file->f_mode & FMODE_READ))
 		goto out;

fs/ocfs2/dlmfs/dlmfs.c

···
 {
 	int status;
 	struct dlmfs_inode_private *ip;
+	struct user_lock_res *lockres;
+	int teardown;
 
 	clear_inode(inode);
 
 	mlog(0, "inode %lu\n", inode->i_ino);
 
 	ip = DLMFS_I(inode);
+	lockres = &ip->ip_lockres;
 
 	if (S_ISREG(inode->i_mode)) {
-		status = user_dlm_destroy_lock(&ip->ip_lockres);
-		if (status < 0)
-			mlog_errno(status);
+		spin_lock(&lockres->l_lock);
+		teardown = !!(lockres->l_flags & USER_LOCK_IN_TEARDOWN);
+		spin_unlock(&lockres->l_lock);
+		if (!teardown) {
+			status = user_dlm_destroy_lock(lockres);
+			if (status < 0)
+				mlog_errno(status);
+		}
 		iput(ip->ip_parent);
 		goto clear_fields;
 	}

fs/ocfs2/heartbeat.c

···
 /*
  * heartbeat.c
  *
- * Register ourselves with the heartbaet service, keep our node maps
+ * Register ourselves with the heartbeat service, keep our node maps
  * up to date, and fire off recovery when needed.
  *
  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
  */
 
+#include <linux/bitmap.h>
 #include <linux/fs.h>
 #include <linux/types.h>
 #include <linux/highmem.h>
···
 
 #include "buffer_head_io.h"
 
-static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
-					    int bit);
-static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
-					      int bit);
-
 /* special case -1 for now
  * TODO: should *really* make sure the calling func never passes -1!!  */
 static void ocfs2_node_map_init(struct ocfs2_node_map *map)
 {
 	map->num_nodes = OCFS2_NODE_MAP_MAX_NODES;
-	memset(map->map, 0, BITS_TO_LONGS(OCFS2_NODE_MAP_MAX_NODES) *
-	       sizeof(unsigned long));
+	bitmap_zero(map->map, OCFS2_NODE_MAP_MAX_NODES);
 }
 
 void ocfs2_init_node_maps(struct ocfs2_super *osb)
···
 	ocfs2_recovery_thread(osb, node_num);
 }
 
-static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
-					    int bit)
-{
-	set_bit(bit, map->map);
-}
-
 void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
 			    struct ocfs2_node_map *map,
 			    int bit)
···
 		return;
 	BUG_ON(bit >= map->num_nodes);
 	spin_lock(&osb->node_map_lock);
-	__ocfs2_node_map_set_bit(map, bit);
+	set_bit(bit, map->map);
 	spin_unlock(&osb->node_map_lock);
-}
-
-static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
-					      int bit)
-{
-	clear_bit(bit, map->map);
 }
 
 void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
···
 		return;
 	BUG_ON(bit >= map->num_nodes);
 	spin_lock(&osb->node_map_lock);
-	__ocfs2_node_map_clear_bit(map, bit);
+	clear_bit(bit, map->map);
 	spin_unlock(&osb->node_map_lock);
 }
 

fs/ocfs2/quota_global.c

···
 	goto out_err;
 }
 
-/* Write information to global quota file. Expects exlusive lock on quota
+/* Write information to global quota file. Expects exclusive lock on quota
  * file inode and quota info */
 static int __ocfs2_global_write_info(struct super_block *sb, int type)
 {

fs/proc/array.c

···
 #include <linux/sched/cputime.h>
 #include <linux/proc_fs.h>
 #include <linux/ioport.h>
-#include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/mm.h>
 #include <linux/hugetlb.h>
···
 {
 	char tcomm[64];
 
+	/*
+	 * Test before PF_KTHREAD because all workqueue worker threads are
+	 * kernel threads.
+	 */
 	if (p->flags & PF_WQ_WORKER)
 		wq_worker_comm(tcomm, sizeof(tcomm), p);
 	else if (p->flags & PF_KTHREAD)

fs/proc/base.c

···
 	put_pid(pid);
 }
 
-struct inode *proc_pid_make_inode(struct super_block * sb,
+struct inode *proc_pid_make_inode(struct super_block *sb,
 				  struct task_struct *task, umode_t mode)
 {
 	struct inode * inode;
···
 
 	/* Let the pid remember us for quick removal */
 	ei->pid = pid;
-	if (S_ISDIR(mode)) {
-		spin_lock(&pid->lock);
-		hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
-		spin_unlock(&pid->lock);
-	}
 
 	task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
 	security_task_to_inode(task, inode);
···
 out_unlock:
 	iput(inode);
 	return NULL;
+}
+
+/*
+ * Generating an inode and adding it into @pid->inodes, so that task will
+ * invalidate inode's dentry before being released.
+ *
+ * This helper is used for creating dir-type entries under '/proc' and
+ * '/proc/<tgid>/task'. Other entries(eg. fd, stat) under '/proc/<tgid>'
+ * can be released by invalidating '/proc/<tgid>' dentry.
+ * In theory, dentries under '/proc/<tgid>/task' can also be released by
+ * invalidating '/proc/<tgid>' dentry, we reserve it to handle single
+ * thread exiting situation: Any one of threads should invalidate its
+ * '/proc/<tgid>/task/<pid>' dentry before released.
+ */
+static struct inode *proc_pid_make_base_inode(struct super_block *sb,
+				struct task_struct *task, umode_t mode)
+{
+	struct inode *inode;
+	struct proc_inode *ei;
+	struct pid *pid;
+
+	inode = proc_pid_make_inode(sb, task, mode);
+	if (!inode)
+		return NULL;
+
+	/* Let proc_flush_pid find this directory inode */
+	ei = PROC_I(inode);
+	pid = ei->pid;
+	spin_lock(&pid->lock);
+	hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
+	spin_unlock(&pid->lock);
+
+	return inode;
 }
 
 int pid_getattr(struct user_namespace *mnt_userns, const struct path *path,
···
 {
 	struct inode *inode;
 
-	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
+	inode = proc_pid_make_base_inode(dentry->d_sb, task,
+					 S_IFDIR | S_IRUGO | S_IXUGO);
 	if (!inode)
 		return ERR_PTR(-ENOENT);
 
···
 	struct task_struct *task, const void *ptr)
 {
 	struct inode *inode;
-	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
+	inode = proc_pid_make_base_inode(dentry->d_sb, task,
+					 S_IFDIR | S_IRUGO | S_IXUGO);
 	if (!inode)
 		return ERR_PTR(-ENOENT);
 

fs/proc/inode.c

···
 #include <linux/mount.h>
 #include <linux/bug.h>
 
-#include <linux/uaccess.h>
-
 #include "internal.h"
 
 static void proc_evict_inode(struct inode *inode)
···
 		complete(pde->pde_unload_completion);
 }
 
-/* pde is locked on entry, unlocked on exit */
+/*
+ * At most 2 contexts can enter this function: the one doing the last
+ * close on the descriptor and whoever is deleting PDE itself.
+ *
+ * First to enter calls ->proc_release hook and signals its completion
+ * to the second one which waits and then does nothing.
+ *
+ * PDE is locked on entry, unlocked on exit.
+ */
 static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
 	__releases(&pde->pde_unload_lock)
 {
···
 	 *
 	 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
 	 * "struct file" needs to be available at the right moment.
-	 *
-	 * Therefore, first process to enter this function does ->release() and
-	 * signals its completion to the other process which does nothing.
 	 */
 	if (pdeo->closing) {
 		/* somebody else is doing that, just wait */
···
 
 		pdeo->closing = true;
 		spin_unlock(&pde->pde_unload_lock);
+
 		file = pdeo->file;
 		pde->proc_ops->proc_release(file_inode(file), file);
+
 		spin_lock(&pde->pde_unload_lock);
-		/* After ->release. */
+		/* Strictly after ->proc_release, see above. */
 		list_del(&pdeo->lh);
 		c = pdeo->c;
 		spin_unlock(&pde->pde_unload_lock);

fs/proc/kmsg.c

···
 #include <linux/fs.h>
 #include <linux/syslog.h>
 
-#include <linux/uaccess.h>
 #include <asm/io.h>
 
 extern wait_queue_head_t log_wait;

fs/proc/nommu.c

···
 #include <linux/seq_file.h>
 #include <linux/hugetlb.h>
 #include <linux/vmalloc.h>
-#include <linux/uaccess.h>
 #include <asm/tlb.h>
 #include <asm/div64.h>
 #include "internal.h"

fs/proc/proc_net.c

···
  *
  *  proc net directory handling functions
  */
-
-#include <linux/uaccess.h>
-
 #include <linux/errno.h>
 #include <linux/time.h>
 #include <linux/proc_fs.h>
···
 	kgid_t gid;
 	int err;
 
+	/*
+	 * This PDE acts only as an anchor for /proc/${pid}/net hierarchy.
+	 * Corresponding inode (PDE(inode) == net->proc_net) is never
+	 * instantiated therefore blanket zeroing is fine.
+	 * net->proc_net_stat inode is instantiated normally.
+	 */
 	err = -ENOMEM;
 	netd = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
 	if (!netd)

fs/proc/proc_tty.c

···
  *
  * Copyright 1997, Theodore Ts'o
  */
-
-#include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/errno.h>

fs/proc/root.c

···
  *
  *  proc root directory handling functions
  */
-
-#include <linux/uaccess.h>
-
 #include <linux/errno.h>
 #include <linux/time.h>
 #include <linux/proc_fs.h>
···
 	proc_mkdir("bus", NULL);
 	proc_sys_init();
 
+	/*
+	 * Last things last. It is not like userspace processes eager
+	 * to open /proc files exist at this point but register last
+	 * anyway.
+	 */
 	register_filesystem(&proc_fs_type);
 }
 

fs/proc/vmcore.c

···
 #include <linux/mutex.h>
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
-#include <linux/uaccess.h>
 #include <linux/uio.h>
 #include <linux/cc_platform.h>
 #include <asm/io.h>

fs/squashfs/Makefile

···
 
 obj-$(CONFIG_SQUASHFS) += squashfs.o
 squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
-squashfs-y += namei.o super.o symlink.o decompressor.o
+squashfs-y += namei.o super.o symlink.o decompressor.o page_actor.o
 squashfs-$(CONFIG_SQUASHFS_FILE_CACHE) += file_cache.o
-squashfs-$(CONFIG_SQUASHFS_FILE_DIRECT) += file_direct.o page_actor.o
+squashfs-$(CONFIG_SQUASHFS_FILE_DIRECT) += file_direct.o
 squashfs-$(CONFIG_SQUASHFS_DECOMP_SINGLE) += decompressor_single.o
 squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI) += decompressor_multi.o
 squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU) += decompressor_multi_percpu.o

fs/squashfs/block.c

···
 			     struct squashfs_page_actor *actor,
 			     int offset, int req_length)
 {
-	void *actor_addr = squashfs_first_page(actor);
+	void *actor_addr;
 	struct bvec_iter_all iter_all = {};
 	struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
 	int copied_bytes = 0;
 	int actor_offset = 0;
+
+	squashfs_actor_nobuff(actor);
+	actor_addr = squashfs_first_page(actor);
 
 	if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all)))
 		return 0;
···
 
 		bytes_to_copy = min_t(int, bytes_to_copy,
 				      req_length - copied_bytes);
-		memcpy(actor_addr + actor_offset, bvec_virt(bvec) + offset,
-		       bytes_to_copy);
+		if (!IS_ERR(actor_addr))
+			memcpy(actor_addr + actor_offset, bvec_virt(bvec) +
+					offset, bytes_to_copy);
 
 		actor_offset += bytes_to_copy;
 		copied_bytes += bytes_to_copy;

fs/squashfs/decompressor.h

···
 		struct bio *, int, int, struct squashfs_page_actor *);
 	int	id;
 	char	*name;
+	int	alloc_buffer;
 	int	supported;
 };
 

fs/squashfs/file.c

···
 #include "squashfs_fs_sb.h"
 #include "squashfs_fs_i.h"
 #include "squashfs.h"
+#include "page_actor.h"
 
 /*
  * Locate cache slot in range [offset, index] for specified inode.  If
···
 	return res;
 }
 
+static int squashfs_readahead_fragment(struct page **page,
+	unsigned int pages, unsigned int expected)
+{
+	struct inode *inode = page[0]->mapping->host;
+	struct squashfs_cache_entry *buffer = squashfs_get_fragment(inode->i_sb,
+		squashfs_i(inode)->fragment_block,
+		squashfs_i(inode)->fragment_size);
+	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+	unsigned int n, mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;
+
+	if (buffer->error)
+		goto out;
+
+	expected += squashfs_i(inode)->fragment_offset;
+
+	for (n = 0; n < pages; n++) {
+		unsigned int base = (page[n]->index & mask) << PAGE_SHIFT;
+		unsigned int offset = base + squashfs_i(inode)->fragment_offset;
+
+		if (expected > offset) {
+			unsigned int avail = min_t(unsigned int, expected -
+				offset, PAGE_SIZE);
+
+			squashfs_fill_page(page[n], buffer, offset, avail);
+		}
+
+		unlock_page(page[n]);
+		put_page(page[n]);
+	}
+
+out:
+	squashfs_cache_put(buffer);
+	return buffer->error;
+}
+
+static void squashfs_readahead(struct readahead_control *ractl)
+{
+	struct inode *inode = ractl->mapping->host;
+	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
+	size_t mask = (1UL << msblk->block_log) - 1;
+	unsigned short shift = msblk->block_log - PAGE_SHIFT;
+	loff_t start = readahead_pos(ractl) & ~mask;
+	size_t len = readahead_length(ractl) + readahead_pos(ractl) - start;
+	struct squashfs_page_actor *actor;
+	unsigned int nr_pages = 0;
+	struct page **pages;
+	int i, file_end = i_size_read(inode) >> msblk->block_log;
+	unsigned int max_pages = 1UL << shift;
+
+	readahead_expand(ractl, start, (len | mask) + 1);
+
+	pages = kmalloc_array(max_pages, sizeof(void *), GFP_KERNEL);
+	if (!pages)
+		return;
+
+	for (;;) {
+		pgoff_t index;
+		int res, bsize;
+		u64 block = 0;
+		unsigned int expected;
+
+		nr_pages = __readahead_batch(ractl, pages, max_pages);
+		if (!nr_pages)
+			break;
+
+		if (readahead_pos(ractl) >= i_size_read(inode))
+			goto skip_pages;
+
+		index = pages[0]->index >> shift;
+		if ((pages[nr_pages - 1]->index >> shift) != index)
+			goto skip_pages;
+
+		expected = index == file_end ?
+			   (i_size_read(inode) & (msblk->block_size - 1)) :
+			    msblk->block_size;
+
+		if (index == file_end && squashfs_i(inode)->fragment_block !=
+						SQUASHFS_INVALID_BLK) {
+			res = squashfs_readahead_fragment(pages, nr_pages,
+							  expected);
+			if (res)
+				goto skip_pages;
+			continue;
+		}
+
+		bsize = read_blocklist(inode, index, &block);
+		if (bsize == 0)
+			goto skip_pages;
+
+		actor = squashfs_page_actor_init_special(msblk, pages, nr_pages,
+							 expected);
+		if (!actor)
+			goto skip_pages;
+
+		res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
+
+		kfree(actor);
+
+		if (res == expected) {
+			int bytes;
+
+			/* Last page (if present) may have trailing bytes not filled */
+			bytes = res % PAGE_SIZE;
+			if (pages[nr_pages - 1]->index == file_end && bytes)
+				memzero_page(pages[nr_pages - 1], bytes,
+					     PAGE_SIZE - bytes);
+
+			for (i = 0; i < nr_pages; i++) {
+				flush_dcache_page(pages[i]);
+				SetPageUptodate(pages[i]);
+			}
+		}
+
+		for (i = 0; i < nr_pages; i++) {
+			unlock_page(pages[i]);
+			put_page(pages[i]);
+		}
+	}
+
+	kfree(pages);
+	return;
+
+skip_pages:
+	for (i = 0; i < nr_pages; i++) {
+		unlock_page(pages[i]);
+		put_page(pages[i]);
+	}
+	kfree(pages);
+}
 
 const struct address_space_operations squashfs_aops = {
-	.read_folio = squashfs_read_folio
+	.read_folio = squashfs_read_folio,
+	.readahead = squashfs_readahead
 };

fs/squashfs/file_direct.c

···
 #include "squashfs.h"
 #include "page_actor.h"
 
-static int squashfs_read_cache(struct page *target_page, u64 block, int bsize,
-	int pages, struct page **page, int bytes);
-
 /* Read separately compressed datablock directly into page cache */
 int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
 	int expected)
···
 	int mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;
 	int start_index = target_page->index & ~mask;
 	int end_index = start_index | mask;
-	int i, n, pages, missing_pages, bytes, res = -ENOMEM;
+	int i, n, pages, bytes, res = -ENOMEM;
 	struct page **page;
 	struct squashfs_page_actor *actor;
 	void *pageaddr;
···
 	if (page == NULL)
 		return res;
 
-	/*
-	 * Create a "page actor" which will kmap and kunmap the
-	 * page cache pages appropriately within the decompressor
-	 */
-	actor = squashfs_page_actor_init_special(page, pages, 0);
-	if (actor == NULL)
-		goto out;
-
 	/* Try to grab all the pages covered by the Squashfs block */
-	for (missing_pages = 0, i = 0, n = start_index; i < pages; i++, n++) {
+	for (i = 0, n = start_index; n <= end_index; n++) {
 		page[i] = (n == target_page->index) ? target_page :
 			grab_cache_page_nowait(target_page->mapping, n);
 
-		if (page[i] == NULL) {
-			missing_pages++;
+		if (page[i] == NULL)
 			continue;
-		}
 
 		if (PageUptodate(page[i])) {
 			unlock_page(page[i]);
 			put_page(page[i]);
-			page[i] = NULL;
-			missing_pages++;
+			continue;
 		}
+
+		i++;
 	}
 
-	if (missing_pages) {
-		/*
-		 * Couldn't get one or more pages, this page has either
-		 * been VM reclaimed, but others are still in the page cache
-		 * and uptodate, or we're racing with another thread in
-		 * squashfs_readpage also trying to grab them.  Fall back to
-		 * using an intermediate buffer.
-		 */
-		res = squashfs_read_cache(target_page, block, bsize, pages,
-							page, expected);
-		if (res < 0)
-			goto mark_errored;
+	pages = i;
 
+	/*
+	 * Create a "page actor" which will kmap and kunmap the
+	 * page cache pages appropriately within the decompressor
+	 */
+	actor = squashfs_page_actor_init_special(msblk, page, pages, expected);
+	if (actor == NULL)
 		goto out;
-	}
 
 	/* Decompress directly into the page cache buffers */
 	res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
+
+	kfree(actor);
+
 	if (res < 0)
 		goto mark_errored;
 
···
 		goto mark_errored;
 	}
 
-	/* Last page may have trailing bytes not filled */
+	/* Last page (if present) may have trailing bytes not filled */
 	bytes = res % PAGE_SIZE;
-	if (bytes) {
-		pageaddr = kmap_atomic(page[pages - 1]);
+	if (page[pages - 1]->index == end_index && bytes) {
+		pageaddr = kmap_local_page(page[pages - 1]);
 		memset(pageaddr + bytes, 0, PAGE_SIZE - bytes);
-		kunmap_atomic(pageaddr);
+		kunmap_local(pageaddr);
 	}
 
 	/* Mark pages as uptodate, unlock and release */
···
 			put_page(page[i]);
 	}
 
-	kfree(actor);
 	kfree(page);
 
 	return 0;
···
 	}
 
 out:
-	kfree(actor);
 	kfree(page);
-	return res;
-}
-
-
-static int squashfs_read_cache(struct page *target_page, u64 block, int bsize,
-	int pages, struct page **page, int bytes)
-{
-	struct inode *i = target_page->mapping->host;
-	struct squashfs_cache_entry *buffer = squashfs_get_datablock(i->i_sb,
-						 block, bsize);
-	int res = buffer->error, n, offset = 0;
-
-	if (res) {
-		ERROR("Unable to read page, block %llx, size %x\n", block,
-			bsize);
-		goto out;
-	}
-
-	for (n = 0; n < pages && bytes > 0; n++,
-			bytes -= PAGE_SIZE, offset += PAGE_SIZE) {
-		int avail = min_t(int, bytes, PAGE_SIZE);
-
-		if (page[n] == NULL)
-			continue;
-
-		squashfs_fill_page(page[n], buffer, offset, avail);
-		unlock_page(page[n]);
-		if (page[n] != target_page)
-			put_page(page[n]);
-	}
-
-out:
-	squashfs_cache_put(buffer);
 	return res;
 }

fs/squashfs/lz4_wrapper.c

···
 	buff = stream->output;
 	while (data) {
 		if (bytes <= PAGE_SIZE) {
-			memcpy(data, buff, bytes);
+			if (!IS_ERR(data))
+				memcpy(data, buff, bytes);
 			break;
 		}
-		memcpy(data, buff, PAGE_SIZE);
+		if (!IS_ERR(data))
+			memcpy(data, buff, PAGE_SIZE);
 		buff += PAGE_SIZE;
 		bytes -= PAGE_SIZE;
 		data = squashfs_next_page(output);
···
 	.decompress = lz4_uncompress,
 	.id = LZ4_COMPRESSION,
 	.name = "lz4",
+	.alloc_buffer = 0,
 	.supported = 1
 };

fs/squashfs/lzo_wrapper.c

···
 	buff = stream->output;
 	while (data) {
 		if (bytes <= PAGE_SIZE) {
-			memcpy(data, buff, bytes);
+			if (!IS_ERR(data))
+				memcpy(data, buff, bytes);
 			break;
 		} else {
-			memcpy(data, buff, PAGE_SIZE);
+			if (!IS_ERR(data))
+				memcpy(data, buff, PAGE_SIZE);
 			buff += PAGE_SIZE;
 			bytes -= PAGE_SIZE;
 			data = squashfs_next_page(output);
···
 	.decompress = lzo_uncompress,
 	.id = LZO_COMPRESSION,
 	.name = "lzo",
+	.alloc_buffer = 0,
 	.supported = 1
 };

fs/squashfs/page_actor.c

···
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
+#include "squashfs_fs_sb.h"
+#include "decompressor.h"
 #include "page_actor.h"
 
 /*
···
 }
 
 /* Implementation of page_actor for decompressing directly into page cache. */
+static void *handle_next_page(struct squashfs_page_actor *actor)
+{
+	int max_pages = (actor->length + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+	if (actor->returned_pages == max_pages)
+		return NULL;
+
+	if ((actor->next_page == actor->pages) ||
+			(actor->next_index != actor->page[actor->next_page]->index)) {
+		if (actor->alloc_buffer) {
+			void *tmp_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
+
+			if (tmp_buffer) {
+				actor->tmp_buffer = tmp_buffer;
+				actor->next_index++;
+				actor->returned_pages++;
+				return tmp_buffer;
+			}
+		}
+
+		actor->next_index++;
+		actor->returned_pages++;
+		return ERR_PTR(-ENOMEM);
+	}
+
+	actor->next_index++;
+	actor->returned_pages++;
+	return actor->pageaddr = kmap_local_page(actor->page[actor->next_page++]);
+}
+
 static void *direct_first_page(struct squashfs_page_actor *actor)
 {
-	actor->next_page = 1;
-	return actor->pageaddr = kmap_atomic(actor->page[0]);
+	return handle_next_page(actor);
 }
 
 static void *direct_next_page(struct squashfs_page_actor *actor)
 {
 	if (actor->pageaddr)
-		kunmap_atomic(actor->pageaddr);
+		kunmap_local(actor->pageaddr);
 
-	return actor->pageaddr = actor->next_page == actor->pages ? NULL :
-		kmap_atomic(actor->page[actor->next_page++]);
+	kfree(actor->tmp_buffer);
+	actor->pageaddr = actor->tmp_buffer = NULL;
+
+	return handle_next_page(actor);
 }
 
 static void direct_finish_page(struct squashfs_page_actor *actor)
 {
 	if (actor->pageaddr)
-		kunmap_atomic(actor->pageaddr);
+		kunmap_local(actor->pageaddr);
+
+	kfree(actor->tmp_buffer);
 }
 
-struct squashfs_page_actor *squashfs_page_actor_init_special(struct page **page,
-	int pages, int length)
+struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_info *msblk,
+	struct page **page, int pages, int length)
 {
 	struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
 
···
 	actor->page = page;
 	actor->pages = pages;
 	actor->next_page = 0;
+	actor->returned_pages = 0;
+	actor->next_index = page[0]->index & ~((1 << (msblk->block_log - PAGE_SHIFT)) - 1);
 	actor->pageaddr = NULL;
+	actor->tmp_buffer = NULL;
+	actor->alloc_buffer = msblk->decompressor->alloc_buffer;
 	actor->squashfs_first_page = direct_first_page;
 	actor->squashfs_next_page = direct_next_page;
 	actor->squashfs_finish_page = direct_finish_page;

fs/squashfs/page_actor.h

···
  * Phillip Lougher <[e-mail]>
  */
 
-#ifndef CONFIG_SQUASHFS_FILE_DIRECT
-struct squashfs_page_actor {
-	void	**page;
-	int	pages;
-	int	length;
-	int	next_page;
-};
-
-static inline struct squashfs_page_actor *squashfs_page_actor_init(void **page,
-	int pages, int length)
-{
-	struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
-
-	if (actor == NULL)
-		return NULL;
-
-	actor->length = length ? : pages * PAGE_SIZE;
-	actor->page = page;
-	actor->pages = pages;
-	actor->next_page = 0;
-	return actor;
-}
-
-static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
-{
-	actor->next_page = 1;
-	return actor->page[0];
-}
-
-static inline void *squashfs_next_page(struct squashfs_page_actor *actor)
-{
-	return actor->next_page == actor->pages ? NULL :
-		actor->page[actor->next_page++];
-}
-
-static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
-{
-	/* empty */
-}
-#else
 struct squashfs_page_actor {
 	union {
 		void		**buffer;
 		struct page	**page;
 	};
 	void	*pageaddr;
+	void	*tmp_buffer;
 	void    *(*squashfs_first_page)(struct squashfs_page_actor *);
 	void    *(*squashfs_next_page)(struct squashfs_page_actor *);
 	void    (*squashfs_finish_page)(struct squashfs_page_actor *);
 	int	pages;
 	int	length;
 	int	next_page;
+	int	alloc_buffer;
+	int	returned_pages;
+	pgoff_t	next_index;
 };
 
-extern struct squashfs_page_actor *squashfs_page_actor_init(void **, int, int);
-extern struct squashfs_page_actor *squashfs_page_actor_init_special(struct page
-							 **, int, int);
+extern struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
+				int pages, int length);
+extern struct squashfs_page_actor *squashfs_page_actor_init_special(
+				struct squashfs_sb_info *msblk,
+				struct page **page, int pages, int length);
 static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
 {
 	return actor->squashfs_first_page(actor);
···
 {
 	actor->squashfs_finish_page(actor);
 }
-#endif
+static inline void squashfs_actor_nobuff(struct squashfs_page_actor *actor)
+{
+	actor->alloc_buffer = 0;
+}
 #endif

fs/squashfs/super.c

···
 #include <linux/module.h>
 #include <linux/magic.h>
 #include <linux/xattr.h>
-#include <linux/backing-dev.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
···
 	return decompressor;
 }
 
-static int squashfs_bdi_init(struct super_block *sb)
-{
-	int err;
-	unsigned int major = MAJOR(sb->s_dev);
-	unsigned int minor = MINOR(sb->s_dev);
-
-	bdi_put(sb->s_bdi);
-	sb->s_bdi = &noop_backing_dev_info;
-
-	err = super_setup_bdi_name(sb, "squashfs_%u_%u", major, minor);
-	if (err)
-		return err;
-
-	sb->s_bdi->ra_pages = 0;
-	sb->s_bdi->io_pages = 0;
-
-	return 0;
-}
 
 static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
···
 	int err;
 
 	TRACE("Entered squashfs_fill_superblock\n");
-
-	/*
-	 * squashfs provides 'backing_dev_info' in order to disable read-ahead. For
-	 * squashfs, I/O is not deferred, it is done immediately in read_folio,
-	 * which means the user would always have to wait their own I/O. So the effect
-	 * of readahead is very weak for squashfs. squashfs_bdi_init will set
-	 * sb->s_bdi->ra_pages and sb->s_bdi->io_pages to 0 and close readahead for
-	 * squashfs.
-	 */
-	err = squashfs_bdi_init(sb);
-	if (err) {
-		errorf(fc, "squashfs init bdi failed");
-		return err;
-	}
 
 	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
 	if (sb->s_fs_info == NULL) {

fs/squashfs/xz_wrapper.c

···
 	stream->buf.out_pos = 0;
 	stream->buf.out_size = PAGE_SIZE;
 	stream->buf.out = squashfs_first_page(output);
+	if (IS_ERR(stream->buf.out)) {
+		error = PTR_ERR(stream->buf.out);
+		goto finish;
+	}
 
 	for (;;) {
 		enum xz_ret xz_err;
···
 
 		if (stream->buf.out_pos == stream->buf.out_size) {
 			stream->buf.out = squashfs_next_page(output);
-			if (stream->buf.out != NULL) {
+			if (IS_ERR(stream->buf.out)) {
+				error = PTR_ERR(stream->buf.out);
+				break;
+			} else if (stream->buf.out != NULL) {
 				stream->buf.out_pos = 0;
 				total += PAGE_SIZE;
 			}
···
 		}
 	}
 
+finish:
 	squashfs_finish_page(output);
 
 	return error ? error : total + stream->buf.out_pos;
···
 	.decompress = squashfs_xz_uncompress,
 	.id = XZ_COMPRESSION,
 	.name = "xz",
+	.alloc_buffer = 1,
 	.supported = 1
 };

fs/squashfs/zlib_wrapper.c

···
 	stream->next_out = squashfs_first_page(output);
 	stream->avail_in = 0;
 
+	if (IS_ERR(stream->next_out)) {
+		error = PTR_ERR(stream->next_out);
+		goto finish;
+	}
+
 	for (;;) {
 		int zlib_err;
 
···
 
 		if (stream->avail_out == 0) {
 			stream->next_out = squashfs_next_page(output);
-			if (stream->next_out != NULL)
+			if (IS_ERR(stream->next_out)) {
+				error = PTR_ERR(stream->next_out);
+				break;
+			} else if (stream->next_out != NULL)
 				stream->avail_out = PAGE_SIZE;
 		}
 
···
 		}
 	}
 
+finish:
 	squashfs_finish_page(output);
 
 	if (!error)
···
 	.decompress = zlib_uncompress,
 	.id = ZLIB_COMPRESSION,
 	.name = "zlib",
+	.alloc_buffer = 1,
 	.supported = 1
 };
 

fs/squashfs/zstd_wrapper.c

···
 
 	out_buf.size = PAGE_SIZE;
 	out_buf.dst = squashfs_first_page(output);
+	if (IS_ERR(out_buf.dst)) {
+		error = PTR_ERR(out_buf.dst);
+		goto finish;
+	}
 
 	for (;;) {
 		size_t zstd_err;
···
 
 		if (out_buf.pos == out_buf.size) {
 			out_buf.dst = squashfs_next_page(output);
-			if (out_buf.dst == NULL) {
+			if (IS_ERR(out_buf.dst)) {
+				error = PTR_ERR(out_buf.dst);
+				break;
+			} else if (out_buf.dst == NULL) {
 				/* Shouldn't run out of pages
 				 * before stream is done.
 				 */
···
 		}
 	}
 
+finish:
+
 	squashfs_finish_page(output);
 
 	return error ? error : total_out;
···
 	.decompress = zstd_uncompress,
 	.id = ZSTD_COMPRESSION,
 	.name = "zstd",
+	.alloc_buffer = 1,
 	.supported = 1
 };

include/linux/backing-dev-defs.h

···
 	WB_start_all,		/* nr_pages == 0 (all) work pending */
 };
 
-enum wb_congested_state {
-	WB_async_congested,	/* The async (write) queue is getting full */
-	WB_sync_congested,	/* The sync queue is getting full */
-};
-
 enum wb_stat_item {
 	WB_RECLAIMABLE,
 	WB_WRITEBACK,
···
 
 	atomic_t writeback_inodes;	/* number of inodes under writeback */
 	struct percpu_counter stat[NR_WB_STAT_ITEMS];
-
-	unsigned long congested;	/* WB_[a]sync_congested flags */
 
 	unsigned long bw_time_stamp;	/* last time write bw is updated */
 	unsigned long dirtied_stamp;

include/linux/compiler-gcc.h

···
 		__builtin_unreachable();	\
 	} while (0)
 
-/*
- * GCC 'asm goto' miscompiles certain code sequences:
- *
- *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
- *
- * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
- *
- * (asm goto is automatically volatile - the naming reflects this.)
- */
-#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
-
 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP)
 #define __HAVE_BUILTIN_BSWAP32__
 #define __HAVE_BUILTIN_BSWAP64__

include/linux/cpumask.h

···
 	return cpu;
 }
 
-#if NR_CPUS == 1
-/* Uniprocessor.  Assume all masks are "1". */
-static inline unsigned int cpumask_first(const struct cpumask *srcp)
-{
-	return 0;
-}
-
-static inline unsigned int cpumask_first_zero(const struct cpumask *srcp)
-{
-	return 0;
-}
-
-static inline unsigned int cpumask_first_and(const struct cpumask *srcp1,
-					     const struct cpumask *srcp2)
-{
-	return 0;
-}
-
-static inline unsigned int cpumask_last(const struct cpumask *srcp)
-{
-	return 0;
-}
-
-/* Valid inputs for n are -1 and 0. */
-static inline unsigned int cpumask_next(int n, const struct cpumask *srcp)
-{
-	return n+1;
-}
-
-static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
-{
-	return n+1;
-}
-
-static inline unsigned int cpumask_next_and(int n,
-					    const struct cpumask *srcp,
-					    const struct cpumask *andp)
-{
-	return n+1;
-}
-
-static inline unsigned int cpumask_next_wrap(int n, const struct cpumask *mask,
-					     int start, bool wrap)
-{
-	/* cpu0 unless stop condition, wrap and at cpu0, then nr_cpumask_bits */
-	return (wrap && n == 0);
-}
-
-/* cpu must be a valid cpu, ie 0, so there's no other choice. */
-static inline unsigned int cpumask_any_but(const struct cpumask *mask,
-					   unsigned int cpu)
-{
-	return 1;
-}
-
-static inline unsigned int cpumask_local_spread(unsigned int i, int node)
-{
-	return 0;
-}
-
-static inline int cpumask_any_and_distribute(const struct cpumask *src1p,
-					     const struct cpumask *src2p) {
-	return cpumask_first_and(src1p, src2p);
-}
-
-static inline int cpumask_any_distribute(const struct cpumask *srcp)
-{
-	return cpumask_first(srcp);
-}
-
-#define for_each_cpu(cpu, mask)			\
-	for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
-#define for_each_cpu_not(cpu, mask)		\
-	for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
-#define for_each_cpu_wrap(cpu, mask, start)	\
-	for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask, (void)(start))
-#define for_each_cpu_and(cpu, mask1, mask2)	\
-	for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask1, (void)mask2)
-#else
 /**
  * cpumask_first - get the first cpu in a cpumask
  * @srcp: the cpumask pointer
···
 
 int __pure cpumask_next_and(int n, const struct cpumask *, const struct cpumask *);
 int __pure cpumask_any_but(const struct cpumask *mask, unsigned int cpu);
+
+#if NR_CPUS == 1
+/* Uniprocessor: there is only one valid CPU */
+static inline unsigned int cpumask_local_spread(unsigned int i, int node)
+{
+	return 0;
+}
+
+static inline int cpumask_any_and_distribute(const struct cpumask *src1p,
+					     const struct cpumask *src2p) {
+	return cpumask_first_and(src1p, src2p);
+}
+
+static inline int cpumask_any_distribute(const struct cpumask *srcp)
+{
+	return cpumask_first(srcp);
+}
+#else
 unsigned int cpumask_local_spread(unsigned int i, int node);
 int cpumask_any_and_distribute(const struct cpumask *src1p,
 			       const struct cpumask *src2p);
 int cpumask_any_distribute(const struct cpumask *srcp);
+#endif /* NR_CPUS */
 
 /**
  * for_each_cpu - iterate over every cpu in a mask
···
 		(cpu) = cpumask_next_zero((cpu), (mask)),	\
 		(cpu) < nr_cpu_ids;)
 
-extern int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap);
+int __pure cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap);
 
 /**
  * for_each_cpu_wrap - iterate over every cpu in a mask, starting at a specified location
···
 	for ((cpu) = -1;						\
 		(cpu) = cpumask_next_and((cpu), (mask1), (mask2)),	\
 		(cpu) < nr_cpu_ids;)
-#endif /* SMP */
 
 #define CPU_BITS_NONE						\
 {								\
···
 /* First bits of cpu_bit_bitmap are in fact unset. */
 #define cpu_none_mask to_cpumask(cpu_bit_bitmap[0])
 
+#if NR_CPUS == 1
+/* Uniprocessor: the possible/online/present masks are always "1" */
+#define for_each_possible_cpu(cpu)	for ((cpu) = 0; (cpu) < 1; (cpu)++)
+#define for_each_online_cpu(cpu)	for ((cpu) = 0; (cpu) < 1; (cpu)++)
+#define for_each_present_cpu(cpu)	for ((cpu) = 0; (cpu) < 1; (cpu)++)
+#else
 #define for_each_possible_cpu(cpu) for_each_cpu((cpu), cpu_possible_mask)
 #define for_each_online_cpu(cpu)   for_each_cpu((cpu), cpu_online_mask)
 #define for_each_present_cpu(cpu)  for_each_cpu((cpu), cpu_present_mask)
+#endif
 
 /* Wrappers for arch boot code to manipulate normally-constant masks */
 void init_cpu_present(const struct cpumask *src);

include/linux/kernel_read_file.h

···
 	return kernel_read_file_str[id];
 }
 
-int kernel_read_file(struct file *file, loff_t offset,
-		     void **buf, size_t buf_size,
-		     size_t *file_size,
-		     enum kernel_read_file_id id);
-int kernel_read_file_from_path(const char *path, loff_t offset,
-			       void **buf, size_t buf_size,
-			       size_t *file_size,
-			       enum kernel_read_file_id id);
-int kernel_read_file_from_path_initns(const char *path, loff_t offset,
-				      void **buf, size_t buf_size,
-				      size_t *file_size,
-				      enum kernel_read_file_id id);
-int kernel_read_file_from_fd(int fd, loff_t offset,
-			     void **buf, size_t buf_size,
-			     size_t *file_size,
-			     enum kernel_read_file_id id);
+ssize_t kernel_read_file(struct file *file, loff_t offset,
+			 void **buf, size_t buf_size,
+			 size_t *file_size,
+			 enum kernel_read_file_id id);
+ssize_t kernel_read_file_from_path(const char *path, loff_t offset,
+				   void **buf, size_t buf_size,
+				   size_t *file_size,
+				   enum kernel_read_file_id id);
+ssize_t kernel_read_file_from_path_initns(const char *path, loff_t offset,
+					  void **buf, size_t buf_size,
+					  size_t *file_size,
+					  enum kernel_read_file_id id);
+ssize_t kernel_read_file_from_fd(int fd, loff_t offset,
+				 void **buf, size_t buf_size,
+				 size_t *file_size,
+				 enum kernel_read_file_id id);
 
 #endif /* _LINUX_KERNEL_READ_FILE_H */

include/linux/kfifo.h

···
  * writer, you don't need extra locking to use these macro.
  */
 #define	kfifo_to_user(fifo, to, len, copied) \
-__kfifo_uint_must_check_helper( \
+__kfifo_int_must_check_helper( \
 ({ \
 	typeof((fifo) + 1) __tmp = (fifo); \
 	void __user *__to = (to); \

include/linux/limits.h

···
 #include <vdso/limits.h>
 
 #define SIZE_MAX	(~(size_t)0)
+#define SSIZE_MAX	((ssize_t)(SIZE_MAX >> 1))
 #define PHYS_ADDR_MAX	(~(phys_addr_t)0)
 
 #define U8_MAX		((u8)~0U)

include/linux/net.h

···
 
 #define net_get_random_once(buf, nbytes)			\
 	get_random_once((buf), (nbytes))
-#define net_get_random_once_wait(buf, nbytes)			\
-	get_random_once_wait((buf), (nbytes))
 
 /*
  * E.g. XFS meta- & log-data is in slab pages, or bcache meta

include/linux/once.h

···
 
 #define get_random_once(buf, nbytes)					     \
 	DO_ONCE(get_random_bytes, (buf), (nbytes))
-#define get_random_once_wait(buf, nbytes)                                    \
-	DO_ONCE(get_random_bytes_wait, (buf), (nbytes))                      \
 
 #endif /* _LINUX_ONCE_H */

include/linux/rbtree.h

···
 #ifndef	_LINUX_RBTREE_H
 #define	_LINUX_RBTREE_H
 
+#include <linux/container_of.h>
 #include <linux/rbtree_types.h>
 
-#include <linux/kernel.h>
 #include <linux/stddef.h>
 #include <linux/rcupdate.h>
 

include/uapi/linux/swab.h

···
 #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
 #else
 #define __swab16(x)				\
-	(__builtin_constant_p((__u16)(x)) ?	\
+	(__u16)(__builtin_constant_p(x) ?	\
 	___constant_swab16(x) :			\
 	__fswab16(x))
 #endif
···
 #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
 #else
 #define __swab32(x)				\
-	(__builtin_constant_p((__u32)(x)) ?	\
+	(__u32)(__builtin_constant_p(x) ?	\
 	___constant_swab32(x) :			\
 	__fswab32(x))
 #endif
···
 #define __swab64(x) (__u64)__builtin_bswap64((__u64)(x))
 #else
 #define __swab64(x)				\
-	(__builtin_constant_p((__u64)(x)) ?	\
+	(__u64)(__builtin_constant_p(x) ?	\
 	___constant_swab64(x) :			\
 	__fswab64(x))
 #endif

init/version.c

···
 #include <linux/build-salt.h>
 #include <linux/elfnote-lto.h>
 #include <linux/export.h>
+#include <linux/init.h>
+#include <linux/printk.h>
 #include <linux/uts.h>
 #include <linux/utsname.h>
 #include <generated/utsrelease.h>
···
 #endif
 };
 EXPORT_SYMBOL_GPL(init_uts_ns);
+
+static int __init early_hostname(char *arg)
+{
+	size_t bufsize = sizeof(init_uts_ns.name.nodename);
+	size_t maxlen  = bufsize - 1;
+	size_t arglen;
+
+	arglen = strlcpy(init_uts_ns.name.nodename, arg, bufsize);
+	if (arglen > maxlen) {
+		pr_warn("hostname parameter exceeds %zd characters and will be truncated",
+			maxlen);
+	}
+	return 0;
+}
+early_param("hostname", early_hostname);
 
 /* FIXED STRINGS! Don't touch! */
 const char linux_banner[] =

ipc/mqueue.c

···
 
 static void init_once(void *foo)
 {
-	struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
+	struct mqueue_inode_info *p = foo;
 
 	inode_init_once(&p->vfs_inode);
 }

kernel/crash_core.c

···
 #include <linux/init.h>
 #include <linux/utsname.h>
 #include <linux/vmalloc.h>
+#include <linux/sizes.h>
 
 #include <asm/page.h>
 #include <asm/sections.h>
 
 #include <crypto/sha1.h>
+
+#include "kallsyms_internal.h"
 
 /* vmcoreinfo stuff */
 unsigned char *vmcoreinfo_data;
···
 					unsigned long long *crash_base)
 {
 	char *cur = cmdline, *tmp;
+	unsigned long long total_mem = system_ram;
+
+	/*
+	 * Firmware sometimes reserves some memory regions for its own use,
+	 * so the system memory size is less than the actual physical memory
+	 * size. Work around this by rounding up the total size to 128M,
+	 * which is enough for most test cases.
+	 */
+	total_mem = roundup(total_mem, SZ_128M);
 
 	/* for each entry of the comma-separated list */
 	do {
···
 			return -EINVAL;
 		}
 		cur = tmp;
-		if (size >= system_ram) {
+		if (size >= total_mem) {
 			pr_warn("crashkernel: invalid size\n");
 			return -EINVAL;
 		}
 
 		/* match ? */
-		if (system_ram >= start && system_ram < end) {
+		if (total_mem >= start && total_mem < end) {
 			*crash_size = size;
 			break;
 		}
···
 #define PAGE_OFFLINE_MAPCOUNT_VALUE	(~PG_offline)
 	VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
 #endif
+
+#ifdef CONFIG_KALLSYMS
+	VMCOREINFO_SYMBOL(kallsyms_names);
+	VMCOREINFO_SYMBOL(kallsyms_token_table);
+	VMCOREINFO_SYMBOL(kallsyms_token_index);
+#ifdef CONFIG_KALLSYMS_BASE_RELATIVE
+	VMCOREINFO_SYMBOL(kallsyms_offsets);
+	VMCOREINFO_SYMBOL(kallsyms_relative_base);
+#else
+	VMCOREINFO_SYMBOL(kallsyms_addresses);
+#endif /* CONFIG_KALLSYMS_BASE_RELATIVE */
+#endif /* CONFIG_KALLSYMS */
 
 	arch_crash_save_vmcoreinfo();
 	update_vmcoreinfo_note();

kernel/hung_task.c

···
  * Process updating of timeout sysctl
  */
 static int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
-				  void __user *buffer,
+				  void *buffer,
 				  size_t *lenp, loff_t *ppos)
 {
 	int ret;

kernel/kallsyms.c

···
 #include <linux/bsearch.h>
 #include <linux/btf_ids.h>
 
-/*
- * These will be re-linked against their real values
- * during the second link stage.
- */
-extern const unsigned long kallsyms_addresses[] __weak;
-extern const int kallsyms_offsets[] __weak;
-extern const u8 kallsyms_names[] __weak;
-
-/*
- * Tell the compiler that the count isn't in the small data section if the arch
- * has one (eg: FRV).
- */
-extern const unsigned int kallsyms_num_syms
-__section(".rodata") __attribute__((weak));
-
-extern const unsigned long kallsyms_relative_base
-__section(".rodata") __attribute__((weak));
-
-extern const char kallsyms_token_table[] __weak;
-extern const u16 kallsyms_token_index[] __weak;
-
-extern const unsigned int kallsyms_markers[] __weak;
+#include "kallsyms_internal.h"
 
 /*
  * Expand a compressed symbol data into the resulting uncompressed string,

kernel/kallsyms_internal.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef LINUX_KALLSYMS_INTERNAL_H_
+#define LINUX_KALLSYMS_INTERNAL_H_
+
+#include <linux/types.h>
+
+/*
+ * These will be re-linked against their real values
+ * during the second link stage.
+ */
+extern const unsigned long kallsyms_addresses[] __weak;
+extern const int kallsyms_offsets[] __weak;
+extern const u8 kallsyms_names[] __weak;
+
+/*
+ * Tell the compiler that the count isn't in the small data section if the arch
+ * has one (eg: FRV).
+ */
+extern const unsigned int kallsyms_num_syms
+__section(".rodata") __attribute__((weak));
+
+extern const unsigned long kallsyms_relative_base
+__section(".rodata") __attribute__((weak));
+
+extern const char kallsyms_token_table[] __weak;
+extern const u16 kallsyms_token_index[] __weak;
+
+extern const unsigned int kallsyms_markers[] __weak;
+
+#endif // LINUX_KALLSYMS_INTERNAL_H_

kernel/kexec_file.c

···
 
 static int kexec_calculate_store_digests(struct kimage *image);
 
+/* Maximum size in bytes for kernel/initrd files. */
+#define KEXEC_FILE_SIZE_MAX	min_t(s64, 4LL << 30, SSIZE_MAX)
+
 /*
  * Currently this is the only default function that is exported as some
  * architectures need it to do additional handlings.
···
 			     const char __user *cmdline_ptr,
 			     unsigned long cmdline_len, unsigned flags)
 {
-	int ret;
+	ssize_t ret;
 	void *ldata;
 
 	ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf,
-				       INT_MAX, NULL, READING_KEXEC_IMAGE);
+				       KEXEC_FILE_SIZE_MAX, NULL,
+				       READING_KEXEC_IMAGE);
 	if (ret < 0)
 		return ret;
 	image->kernel_buf_len = ret;
···
 	/* It is possible that there no initramfs is being loaded */
 	if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
 		ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,
-					       INT_MAX, NULL,
+					       KEXEC_FILE_SIZE_MAX, NULL,
 					       READING_KEXEC_INITRAMFS);
 		if (ret < 0)
 			goto out;

kernel/profile.c

···
 
 	/* only text is profiled */
 	prof_len = (_etext - _stext) >> prof_shift;
+
+	if (!prof_len) {
+		pr_warn("profiling shift: %u too large\n", prof_shift);
+		prof_on = 0;
+		return -EINVAL;
+	}
+
 	buffer_bytes = prof_len*sizeof(atomic_t);
 
 	if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
···
 	return read;
 }
 
+/* default is to not implement this call */
+int __weak setup_profiling_timer(unsigned mult)
+{
+	return -EINVAL;
+}
+
 /*
  * Writing to /proc/profile resets the counters
  *
···
 			     size_t count, loff_t *ppos)
 {
 #ifdef CONFIG_SMP
-	extern int setup_profiling_timer(unsigned int multiplier);
-
 	if (count == sizeof(int)) {
 		unsigned int multiplier;
 

lib/Kconfig

···
 	bool
 	select STACKDEPOT
 
-config STACK_HASH_ORDER
-	int "stack depot hash size (12 => 4KB, 20 => 1024KB)"
-	range 12 20
-	default 20
-	depends on STACKDEPOT
-	help
-	 Select the hash size as a power of 2 for the stackdepot hash table.
-	 Choose a lower value to reduce the memory impact.
-
 config REF_TRACKER
 	bool
 	depends on STACKTRACE_SUPPORT

lib/Kconfig.debug

···
 	Documentation on how to use the module can be found in
 	Documentation/fault-injection/provoke-crashes.rst
 
+config TEST_CPUMASK
+	tristate "cpumask tests" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Enable to turn on cpumask tests, running at boot or module load time.
+
+	  If unsure, say N.
+
 config TEST_LIST_SORT
 	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
 	depends on KUNIT

lib/Makefile

···
 	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
 	 earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
 	 nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o \
-	 buildid.o
+	 buildid.o cpumask.o
 
 lib-$(CONFIG_PRINTK) += dump_stack.o
-lib-$(CONFIG_SMP) += cpumask.o
 
 lib-y	+= kobject.o klist.o
 obj-y	+= lockref.o
···
 obj-$(CONFIG_TEST_FREE_PAGES) += test_free_pages.o
 obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
 obj-$(CONFIG_TEST_REF_TRACKER) += test_ref_tracker.o
+obj-$(CONFIG_TEST_CPUMASK) += test_cpumask.o
 CFLAGS_test_fprobe.o += $(CC_FLAGS_FTRACE)
 obj-$(CONFIG_FPROBE_SANITY_TEST) += test_fprobe.o
 #

lib/btree.c

···
 	return 1;
 }
 
-void *btree_lookup(struct btree_head *head, struct btree_geo *geo,
+static void *btree_lookup_node(struct btree_head *head, struct btree_geo *geo,
 		unsigned long *key)
 {
 	int i, height = head->height;
···
 		if (!node)
 			return NULL;
 	}
+	return node;
+}
 
+void *btree_lookup(struct btree_head *head, struct btree_geo *geo,
+		unsigned long *key)
+{
+	int i;
+	unsigned long *node;
+
+	node = btree_lookup_node(head, geo, key);
 	if (!node)
 		return NULL;
 
···
 int btree_update(struct btree_head *head, struct btree_geo *geo,
 		 unsigned long *key, void *val)
 {
-	int i, height = head->height;
-	unsigned long *node = head->node;
+	int i;
+	unsigned long *node;
 
-	if (height == 0)
-		return -ENOENT;
-
-	for ( ; height > 1; height--) {
-		for (i = 0; i < geo->no_pairs; i++)
-			if (keycmp(geo, node, i, key) <= 0)
-				break;
-		if (i == geo->no_pairs)
-			return -ENOENT;
-		node = bval(geo, node, i);
-		if (!node)
-			return -ENOENT;
-	}
-
+	node = btree_lookup_node(head, geo, key);
 	if (!node)
 		return -ENOENT;
 

lib/cpumask.c

···
 }
 #endif
 
+#if NR_CPUS > 1
 /**
  * cpumask_local_spread - select the i'th cpu with local numa cpu's first
  * @i: index number
···
 	return next;
 }
 EXPORT_SYMBOL(cpumask_any_distribute);
+#endif /* NR_CPUS */

lib/devres.c

···
 {
 	void __iomem **ptr, *addr = NULL;
 
-	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
+	ptr = devres_alloc_node(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL,
+				dev_to_node(dev));
 	if (!ptr)
 		return NULL;
 
···
 {
 	void __iomem **ptr, *addr;
 
-	ptr = devres_alloc(devm_ioport_map_release, sizeof(*ptr), GFP_KERNEL);
+	ptr = devres_alloc_node(devm_ioport_map_release, sizeof(*ptr), GFP_KERNEL,
+				dev_to_node(dev));
 	if (!ptr)
 		return NULL;
 
···
 	if (dr)
 		return dr->table;
 
-	new_dr = devres_alloc(pcim_iomap_release, sizeof(*new_dr), GFP_KERNEL);
+	new_dr = devres_alloc_node(pcim_iomap_release, sizeof(*new_dr), GFP_KERNEL,
+				   dev_to_node(&pdev->dev));
 	if (!new_dr)
 		return NULL;
 	dr = devres_get(&pdev->dev, new_dr, NULL, NULL);
···
 	int *mtrr;
 	int ret;
 
-	mtrr = devres_alloc(devm_arch_phys_ac_add_release, sizeof(*mtrr), GFP_KERNEL);
+	mtrr = devres_alloc_node(devm_arch_phys_ac_add_release, sizeof(*mtrr), GFP_KERNEL,
+				 dev_to_node(dev));
 	if (!mtrr)
 		return -ENOMEM;
 
···
 	struct arch_io_reserve_memtype_wc_devres *dr;
 	int ret;
 
-	dr = devres_alloc(devm_arch_io_free_memtype_wc_release, sizeof(*dr), GFP_KERNEL);
+	dr = devres_alloc_node(devm_arch_io_free_memtype_wc_release, sizeof(*dr), GFP_KERNEL,
+			       dev_to_node(dev));
 	if (!dr)
 		return -ENOMEM;
 

lib/error-inject.c

···
 int get_injectable_error_type(unsigned long addr)
 {
 	struct ei_entry *ent;
+	int ei_type = EI_ETYPE_NONE;
 
+	mutex_lock(&ei_mutex);
 	list_for_each_entry(ent, &error_injection_list, list) {
-		if (addr >= ent->start_addr && addr < ent->end_addr)
-			return ent->etype;
+		if (addr >= ent->start_addr && addr < ent->end_addr) {
+			ei_type = ent->etype;
+			break;
+		}
 	}
-	return EI_ETYPE_NONE;
+	mutex_unlock(&ei_mutex);
+
+	return ei_type;
 }
 
 /*
···
 	return 0;
 }
 
-static const struct seq_operations ei_seq_ops = {
+static const struct seq_operations ei_sops = {
 	.start = ei_seq_start,
 	.next  = ei_seq_next,
 	.stop  = ei_seq_stop,
 	.show  = ei_seq_show,
 };
 
-static int ei_open(struct inode *inode, struct file *filp)
-{
-	return seq_open(filp, &ei_seq_ops);
-}
-
-static const struct file_operations debugfs_ei_ops = {
-	.open           = ei_open,
-	.read           = seq_read,
-	.llseek         = seq_lseek,
-	.release        = seq_release,
-};
+DEFINE_SEQ_ATTRIBUTE(ei);
 
 static int __init ei_debugfs_init(void)
 {
···
 	if (!dir)
 		return -ENOMEM;
 
-	file = debugfs_create_file("list", 0444, dir, NULL, &debugfs_ei_ops);
+	file = debugfs_create_file("list", 0444, dir, NULL, &ei_fops);
 	if (!file) {
 		debugfs_remove(dir);
 		return -ENOMEM;

lib/flex_proportions.c

···
  */
 bool fprop_new_period(struct fprop_global *p, int periods)
 {
-	s64 events;
-	unsigned long flags;
+	s64 events = percpu_counter_sum(&p->events);
 
-	local_irq_save(flags);
-	events = percpu_counter_sum(&p->events);
 	/*
 	 * Don't do anything if there are no events.
 	 */
-	if (events <= 1) {
-		local_irq_restore(flags);
+	if (events <= 1)
 		return false;
-	}
 	write_seqcount_begin(&p->sequence);
 	if (periods < 64)
 		events -= events >> periods;
···
 	percpu_counter_add(&p->events, -events);
 	p->period += periods;
 	write_seqcount_end(&p->sequence);
-	local_irq_restore(flags);
 
 	return true;
 }

lib/list_debug.c

···
 bool __list_add_valid(struct list_head *new, struct list_head *prev,
 		      struct list_head *next)
 {
-	if (CHECK_DATA_CORRUPTION(next->prev != prev,
+	if (CHECK_DATA_CORRUPTION(prev == NULL,
+			"list_add corruption. prev is NULL.\n") ||
+	    CHECK_DATA_CORRUPTION(next == NULL,
+			"list_add corruption. next is NULL.\n") ||
+	    CHECK_DATA_CORRUPTION(next->prev != prev,
 			"list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).\n",
 			prev, next->prev, next) ||
 	    CHECK_DATA_CORRUPTION(prev->next != next,
···
 	prev = entry->prev;
 	next = entry->next;
 
-	if (CHECK_DATA_CORRUPTION(next == LIST_POISON1,
+	if (CHECK_DATA_CORRUPTION(next == NULL,
+			"list_del corruption, %px->next is NULL\n", entry) ||
+	    CHECK_DATA_CORRUPTION(prev == NULL,
+			"list_del corruption, %px->prev is NULL\n", entry) ||
+	    CHECK_DATA_CORRUPTION(next == LIST_POISON1,
 			"list_del corruption, %px->next is LIST_POISON1 (%px)\n",
 			entry, LIST_POISON1) ||
 	    CHECK_DATA_CORRUPTION(prev == LIST_POISON2,

lib/lru_cache.c

···
 		return lc;
 
 	/* else: could not allocate all elements, give up */
-	for (i--; i; i--) {
-		void *p = element[i];
+	while (i) {
+		void *p = element[--i];
 		kmem_cache_free(cache, p - e_off);
 	}
 	kfree(lc);

lib/lz4/lz4_decompress.c

···
 				      (BYTE *)dest - prefixSize, NULL, 0);
 }
 
-int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
-				     int compressedSize, int maxOutputSize,
-				     const void *dictStart, size_t dictSize)
+static int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
+					    int compressedSize, int maxOutputSize,
+					    const void *dictStart, size_t dictSize)
 {
 	return LZ4_decompress_generic(source, dest,
 				      compressedSize, maxOutputSize,

lib/lzo/lzo1x_compress.c

···
 
 		if (dv == 0 && bitstream_version) {
 			const unsigned char *ir = ip + 4;
-			const unsigned char *limit = ip_end
-				< (ip + MAX_ZERO_RUN_LENGTH + 1)
-				? ip_end : ip + MAX_ZERO_RUN_LENGTH + 1;
+			const unsigned char *limit = min(ip_end, ip + MAX_ZERO_RUN_LENGTH + 1);
 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && \
 	defined(LZO_FAST_64BIT_MEMORY_ACCESS)
 			u64 dv64;
···
 	data_start = op;
 
 	while (l > 20) {
-		size_t ll = l <= (m4_max_offset + 1) ? l : (m4_max_offset + 1);
+		size_t ll = min_t(size_t, l, m4_max_offset + 1);
 		uintptr_t ll_end = (uintptr_t) ip + ll;
 		if ((ll_end + ((t + ll) >> 5)) <= ll_end)
 			break;

lib/mpi/mpiutil.c

···
 	if (!w)
 		w = mpi_alloc(1);
 	/* FIXME: If U is 0 we have no need to resize and thus possible
-	 * allocating the the limbs.
+	 * allocating the limbs.
 	 */
 	RESIZE_IF_NEEDED(w, 1);
 	w->d[0] = u;

lib/radix-tree.c

···
 }
 
 static inline int insert_entries(struct radix_tree_node *node,
-		void __rcu **slot, void *item, bool replace)
+		void __rcu **slot, void *item)
 {
 	if (*slot)
 		return -EEXIST;
···
 	if (error)
 		return error;
 
-	error = insert_entries(node, slot, item, false);
+	error = insert_entries(node, slot, item);
 	if (error < 0)
 		return error;
 

lib/scatterlist.c

···
  **/
 void sg_free_append_table(struct sg_append_table *table)
 {
-	__sg_free_table(&table->sgt, SG_MAX_SINGLE_ALLOC, false, sg_kfree,
+	__sg_free_table(&table->sgt, SG_MAX_SINGLE_ALLOC, 0, sg_kfree,
 			table->total_nents);
 }
 EXPORT_SYMBOL(sg_free_append_table);
···
  **/
 void sg_free_table(struct sg_table *table)
 {
-	__sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree,
+	__sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree,
 			table->orig_nents);
 }
 EXPORT_SYMBOL(sg_free_table);

lib/smp_processor_id.c

···
 
 	printk("caller is %pS\n", __builtin_return_address(0));
 	dump_stack();
-	instrumentation_end();
 
 out_enable:
+	instrumentation_end();
 	preempt_enable_no_resched_notrace();
 out:
 	return this_cpu;

lib/stackdepot.c

···
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/memblock.h>
+#include <linux/kasan-enabled.h>
 
 #define DEPOT_STACK_BITS (sizeof(depot_stack_handle_t) * 8)
 
···
 	return stack;
 }
 
-#define STACK_HASH_SIZE (1L << CONFIG_STACK_HASH_ORDER)
-#define STACK_HASH_MASK (STACK_HASH_SIZE - 1)
+/* one hash table bucket entry per 16kB of memory */
+#define STACK_HASH_SCALE	14
+/* limited between 4k and 1M buckets */
+#define STACK_HASH_ORDER_MIN	12
+#define STACK_HASH_ORDER_MAX	20
 #define STACK_HASH_SEED 0x9747b28c
+
+static unsigned int stack_hash_order;
+static unsigned int stack_hash_mask;
 
 static bool stack_depot_disable;
 static struct stack_record **stack_table;
···
 
 int __init stack_depot_early_init(void)
 {
-	size_t size;
+	unsigned long entries = 0;
 
 	/* This is supposed to be called only once, from mm_init() */
 	if (WARN_ON(__stack_depot_early_init_passed))
···
 
 	__stack_depot_early_init_passed = true;
 
+	if (kasan_enabled() && !stack_hash_order)
+		stack_hash_order = STACK_HASH_ORDER_MAX;
+
 	if (!__stack_depot_want_early_init || stack_depot_disable)
 		return 0;
 
-	size = (STACK_HASH_SIZE * sizeof(struct stack_record *));
-	pr_info("Stack Depot early init allocating hash table with memblock_alloc, %zu bytes\n",
-		size);
-	stack_table = memblock_alloc(size, SMP_CACHE_BYTES);
+	if (stack_hash_order)
+		entries = 1UL <<  stack_hash_order;
+	stack_table = alloc_large_system_hash("stackdepot",
+						sizeof(struct stack_record *),
+						entries,
+						STACK_HASH_SCALE,
+						HASH_EARLY | HASH_ZERO,
+						NULL,
+						&stack_hash_mask,
+						1UL << STACK_HASH_ORDER_MIN,
+						1UL << STACK_HASH_ORDER_MAX);
 
 	if (!stack_table) {
 		pr_err("Stack Depot hash table allocation failed, disabling\n");
···
 
 	mutex_lock(&stack_depot_init_mutex);
 	if (!stack_depot_disable && !stack_table) {
-		pr_info("Stack Depot allocating hash table with kvcalloc\n");
-		stack_table = kvcalloc(STACK_HASH_SIZE, sizeof(struct stack_record *), GFP_KERNEL);
+		unsigned long entries;
+		int scale = STACK_HASH_SCALE;
+
+		if (stack_hash_order) {
+			entries = 1UL << stack_hash_order;
+		} else {
+			entries = nr_free_buffer_pages();
+			entries = roundup_pow_of_two(entries);
+
+			if (scale > PAGE_SHIFT)
+				entries >>= (scale - PAGE_SHIFT);
+			else
+				entries <<= (PAGE_SHIFT - scale);
+		}
+
+		if (entries < 1UL << STACK_HASH_ORDER_MIN)
+			entries = 1UL << STACK_HASH_ORDER_MIN;
+		if (entries > 1UL << STACK_HASH_ORDER_MAX)
+			entries = 1UL << STACK_HASH_ORDER_MAX;
+
+		pr_info("Stack Depot allocating hash table of %lu entries with kvcalloc\n",
+				entries);
+		stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL);
 		if (!stack_table) {
 			pr_err("Stack Depot hash table allocation failed, disabling\n");
 			stack_depot_disable = true;
 			ret = -ENOMEM;
 		}
+		stack_hash_mask = entries - 1;
 	}
 	mutex_unlock(&stack_depot_init_mutex);
 	return ret;
···
 		goto fast_exit;
 
 	hash = hash_stack(entries, nr_entries);
-	bucket = &stack_table[hash & STACK_HASH_MASK];
+	bucket = &stack_table[hash & stack_hash_mask];
 
 	/*
 	 * Fast path: look the stack trace up without locking.

lib/test_cpumask.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * KUnit tests for cpumask.
+ *
+ * Author: Sander Vanheule <[e-mail]>
+ */
+
+#include <kunit/test.h>
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+
+#define EXPECT_FOR_EACH_CPU_EQ(test, mask)			\
+	do {							\
+		const cpumask_t *m = (mask);			\
+		int mask_weight = cpumask_weight(m);		\
+		int cpu, iter = 0;				\
+		for_each_cpu(cpu, m)				\
+			iter++;					\
+		KUNIT_EXPECT_EQ((test), mask_weight, iter);	\
+	} while (0)
+
+#define EXPECT_FOR_EACH_CPU_NOT_EQ(test, mask)					\
+	do {									\
+		const cpumask_t *m = (mask);					\
+		int mask_weight = cpumask_weight(m);				\
+		int cpu, iter = 0;						\
+		for_each_cpu_not(cpu, m)					\
+			iter++;							\
+		KUNIT_EXPECT_EQ((test), nr_cpu_ids - mask_weight, iter);	\
+	} while (0)
+
+#define EXPECT_FOR_EACH_CPU_WRAP_EQ(test, mask)			\
+	do {							\
+		const cpumask_t *m = (mask);			\
+		int mask_weight = cpumask_weight(m);		\
+		int cpu, iter = 0;				\
+		for_each_cpu_wrap(cpu, m, nr_cpu_ids / 2)	\
+			iter++;					\
+		KUNIT_EXPECT_EQ((test), mask_weight, iter);	\
+	} while (0)
+
+#define EXPECT_FOR_EACH_CPU_BUILTIN_EQ(test, name)		\
+	do {							\
+		int mask_weight = num_##name##_cpus();		\
+		int cpu, iter = 0;				\
+		for_each_##name##_cpu(cpu)			\
+			iter++;					\
+		KUNIT_EXPECT_EQ((test), mask_weight, iter);	\
+	} while (0)
+
+static cpumask_t mask_empty;
+static cpumask_t mask_all;
+
+static void test_cpumask_weight(struct kunit *test)
+{
+	KUNIT_EXPECT_TRUE(test, cpumask_empty(&mask_empty));
+	KUNIT_EXPECT_TRUE(test, cpumask_full(cpu_possible_mask));
+	KUNIT_EXPECT_TRUE(test, cpumask_full(&mask_all));
+
+	KUNIT_EXPECT_EQ(test, 0, cpumask_weight(&mask_empty));
+	KUNIT_EXPECT_EQ(test, nr_cpu_ids, cpumask_weight(cpu_possible_mask));
+	KUNIT_EXPECT_EQ(test, nr_cpumask_bits, cpumask_weight(&mask_all));
+}
+
+static void test_cpumask_first(struct kunit *test)
+{
+	KUNIT_EXPECT_LE(test, nr_cpu_ids, cpumask_first(&mask_empty));
+	KUNIT_EXPECT_EQ(test, 0, cpumask_first(cpu_possible_mask));
+
+	KUNIT_EXPECT_EQ(test, 0, cpumask_first_zero(&mask_empty));
+	KUNIT_EXPECT_LE(test, nr_cpu_ids, cpumask_first_zero(cpu_possible_mask));
+}
+
+static void test_cpumask_last(struct kunit *test)
+{
+	KUNIT_EXPECT_LE(test, nr_cpumask_bits, cpumask_last(&mask_empty));
+	KUNIT_EXPECT_EQ(test, nr_cpumask_bits - 1, cpumask_last(cpu_possible_mask));
+}
+
+static void test_cpumask_next(struct kunit *test)
+{
+	KUNIT_EXPECT_EQ(test, 0, cpumask_next_zero(-1, &mask_empty));
+	KUNIT_EXPECT_LE(test, nr_cpu_ids, cpumask_next_zero(-1, cpu_possible_mask));
+
+	KUNIT_EXPECT_LE(test, nr_cpu_ids, cpumask_next(-1, &mask_empty));
+	KUNIT_EXPECT_EQ(test, 0, cpumask_next(-1, cpu_possible_mask));
+}
+
+static void test_cpumask_iterators(struct kunit *test)
+{
+	EXPECT_FOR_EACH_CPU_EQ(test, &mask_empty);
+	EXPECT_FOR_EACH_CPU_NOT_EQ(test, &mask_empty);
+	EXPECT_FOR_EACH_CPU_WRAP_EQ(test, &mask_empty);
+
+	EXPECT_FOR_EACH_CPU_EQ(test, cpu_possible_mask);
+	EXPECT_FOR_EACH_CPU_NOT_EQ(test, cpu_possible_mask);
+	EXPECT_FOR_EACH_CPU_WRAP_EQ(test, cpu_possible_mask);
+}
+
+static void test_cpumask_iterators_builtin(struct kunit *test)
+{
+	EXPECT_FOR_EACH_CPU_BUILTIN_EQ(test, possible);
+
+	/* Ensure the dynamic masks are stable while running the tests */
+	cpu_hotplug_disable();
+
+	EXPECT_FOR_EACH_CPU_BUILTIN_EQ(test, online);
+	EXPECT_FOR_EACH_CPU_BUILTIN_EQ(test, present);
+
+	cpu_hotplug_enable();
+}
+
+static int test_cpumask_init(struct kunit *test)
+{
+	cpumask_clear(&mask_empty);
+	cpumask_setall(&mask_all);
+
+	return 0;
+}
+
+static struct kunit_case test_cpumask_cases[] = {
+	KUNIT_CASE(test_cpumask_weight),
+	KUNIT_CASE(test_cpumask_first),
+	KUNIT_CASE(test_cpumask_last),
+	KUNIT_CASE(test_cpumask_next),
+	KUNIT_CASE(test_cpumask_iterators),
+	KUNIT_CASE(test_cpumask_iterators_builtin),
+	{}
+};
+
+static struct kunit_suite test_cpumask_suite = {
+	.name = "cpumask",
+	.init = test_cpumask_init,
+	.test_cases = test_cpumask_cases,
+};
+kunit_test_suite(test_cpumask_suite);
+
+MODULE_LICENSE("GPL");

lib/ts_bm.c

···
 
 			/* London calling... */
 			DEBUGP("found!\n");
-			return consumed += (shift-(bm->patlen-1));
+			return consumed + (shift-(bm->patlen-1));
 
 next:			bs = bm->bad_shift[text[shift-i]];
 

scripts/bloat-o-meter

···
 # This software may be used and distributed according to the terms
 # of the GNU General Public License, incorporated herein by reference.
 
-import sys, os, re
+import sys, os, re, argparse
 from signal import signal, SIGPIPE, SIG_DFL
 
 signal(SIGPIPE, SIG_DFL)
 
-if len(sys.argv) < 3:
-    sys.stderr.write("usage: %s [option] file1 file2\n" % sys.argv[0])
-    sys.stderr.write("The options are:\n")
-    sys.stderr.write("-c	categorize output based on symbol type\n")
-    sys.stderr.write("-d	Show delta of Data Section\n")
-    sys.stderr.write("-t	Show delta of text Section\n")
-    sys.exit(-1)
+parser = argparse.ArgumentParser(description="Simple script used to compare the symbol sizes of 2 object files")
+group = parser.add_mutually_exclusive_group()
+group.add_argument('-c', help='categorize output based on symbol type', action='store_true')
+group.add_argument('-d', help='Show delta of Data Section', action='store_true')
+group.add_argument('-t', help='Show delta of text Section', action='store_true')
+parser.add_argument('-p', dest='prefix', help='Arch prefix for the tool being used. Useful in cross build scenarios')
+parser.add_argument('file1', help='First file to compare')
+parser.add_argument('file2', help='Second file to compare')
+
+args = parser.parse_args()
 
 re_NUMBER = re.compile(r'\.[0-9]+')
 
 def getsizes(file, format):
     sym = {}
-    with os.popen("nm --size-sort " + file) as f:
+    nm = "nm"
+    if args.prefix:
+        nm = "{}nm".format(args.prefix)
+
+    with os.popen("{} --size-sort {}".format(nm, file)) as f:
         for line in f:
             if line.startswith("\n") or ":" in line:
                 continue
···
     delta.reverse()
     return grow, shrink, add, remove, up, down, delta, old, new, otot, ntot
 
-def print_result(symboltype, symbolformat, argc):
+def print_result(symboltype, symbolformat):
     grow, shrink, add, remove, up, down, delta, old, new, otot, ntot = \
-    calc(sys.argv[argc - 1], sys.argv[argc], symbolformat)
+    calc(args.file1, args.file2, symbolformat)
 
     print("add/remove: %s/%s grow/shrink: %s/%s up/down: %s/%s (%s)" % \
           (add, remove, grow, shrink, up, -down, up-down))
···
         percent = 0
     print("Total: Before=%d, After=%d, chg %+.2f%%" % (otot, ntot, percent))
 
-if sys.argv[1] == "-c":
-    print_result("Function", "tT", 3)
-    print_result("Data", "dDbB", 3)
-    print_result("RO Data", "rR", 3)
-elif sys.argv[1] == "-d":
-    print_result("Data", "dDbBrR", 3)
-elif sys.argv[1] == "-t":
-    print_result("Function", "tT", 3)
+if args.c:
+    print_result("Function", "tT")
+    print_result("Data", "dDbB")
+    print_result("RO Data", "rR")
+elif args.d:
+    print_result("Data", "dDbBrR")
+elif args.t:
+    print_result("Function", "tT")
 else:
-    print_result("Function", "tTdDbBrR", 2)
+    print_result("Function", "tTdDbBrR")

scripts/checkpatch.pl

···
 our $declaration_macros = qr{(?x:
 	(?:$Storage\s+)?(?:[A-Z_][A-Z0-9]*_){0,2}(?:DEFINE|DECLARE)(?:_[A-Z0-9]+){1,6}\s*\(|
 	(?:$Storage\s+)?[HLP]?LIST_HEAD\s*\(|
-	(?:SKCIPHER_REQUEST|SHASH_DESC|AHASH_REQUEST)_ON_STACK\s*\(
+	(?:SKCIPHER_REQUEST|SHASH_DESC|AHASH_REQUEST)_ON_STACK\s*\(|
+	(?:$Storage\s+)?(?:XA_STATE|XA_STATE_ORDER)\s*\(
 )};
 
 our %allow_repeated_words = (
···
 			    $var !~ /^(?:[a-z0-9_]*|[A-Z0-9_]*)?_?[a-z][A-Z](?:_[a-z0-9_]+|_[A-Z0-9_]+)?$/ &&
 #Ignore some three character SI units explicitly, like MiB and KHz
 			    $var !~ /^(?:[a-z_]*?)_?(?:[KMGT]iB|[KMGT]?Hz)(?:_[a-z_]+)?$/) {
-				while ($var =~ m{($Ident)}g) {
+				while ($var =~ m{\b($Ident)}g) {
 					my $word = $1;
 					next if ($word !~ /[A-Z][a-z]|[a-z][A-Z]/);
 					if ($check) {

scripts/gdb/vmlinux-gdb.py

···
 
 import os
 
-sys.path.insert(0, os.path.dirname(__file__) + "/scripts/gdb")
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)) + "/scripts/gdb")
 
 try:
     gdb.parse_and_eval("0")

tools/accounting/getdelays.c

···
 		exit(code);			\
 	} while (0)
 
-int done;
 int rcvbufsz;
 char name[100];
 int dbg;
···
 	pid_t rtid = 0;
 
 	int fd = 0;
-	int count = 0;
 	int write_file = 0;
 	int maskset = 0;
 	char *logfile = NULL;
···
 				len2 = 0;
 				/* For nested attributes, na follows */
 				na = (struct nlattr *) NLA_DATA(na);
-				done = 0;
 				while (len2 < aggr_len) {
 					switch (na->nla_type) {
 					case TASKSTATS_TYPE_PID:
···
 							printf("TGID\t%d\n", rtid);
 						break;
 					case TASKSTATS_TYPE_STATS:
-						count++;
 						if (print_delays)
 							print_delayacct((struct taskstats *) NLA_DATA(na));
 						if (print_io_accounting)

tools/testing/selftests/Makefile

···
 TARGETS += filesystems
 TARGETS += filesystems/binderfs
 TARGETS += filesystems/epoll
+TARGETS += filesystems/fat
 TARGETS += firmware
 TARGETS += fpu
 TARGETS += ftrace

tools/testing/selftests/filesystems/fat/.gitignore

···
+# SPDX-License-Identifier: GPL-2.0-only
+rename_exchange

tools/testing/selftests/filesystems/fat/Makefile

···
+# SPDX-License-Identifier: GPL-2.0
+
+TEST_PROGS := run_fat_tests.sh
+TEST_GEN_PROGS_EXTENDED := rename_exchange
+CFLAGS += -O2 -g -Wall $(KHDR_INCLUDES)
+
+include ../../lib.mk

tools/testing/selftests/filesystems/fat/config

···
+CONFIG_BLK_DEV_LOOP=y
+CONFIG_VFAT_FS=y

tools/testing/selftests/filesystems/fat/rename_exchange.c

···
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Program that atomically exchanges two paths using
+ * the renameat2() system call RENAME_EXCHANGE flag.
+ *
+ * Copyright 2022 Red Hat Inc.
+ * Author: Javier Martinez Canillas <[e-mail]>
+ */
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+void print_usage(const char *program)
+{
+	printf("Usage: %s [oldpath] [newpath]\n", program);
+	printf("Atomically exchange oldpath and newpath\n");
+}
+
+int main(int argc, char *argv[])
+{
+	int ret;
+
+	if (argc != 3) {
+		print_usage(argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	ret = renameat2(AT_FDCWD, argv[1], AT_FDCWD, argv[2], RENAME_EXCHANGE);
+	if (ret) {
+		perror("rename exchange failed");
+		exit(EXIT_FAILURE);
+	}
+
+	exit(EXIT_SUCCESS);
+}

tools/testing/selftests/filesystems/fat/run_fat_tests.sh

···
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Run filesystem operations tests on an 1 MiB disk image that is formatted with
+# a vfat filesystem and mounted in a temporary directory using a loop device.
+#
+# Copyright 2022 Red Hat Inc.
+# Author: Javier Martinez Canillas <[e-mail]>
+
+set -e
+set -u
+set -o pipefail
+
+BASE_DIR="$(dirname $0)"
+TMP_DIR="$(mktemp -d /tmp/fat_tests_tmp.XXXX)"
+IMG_PATH="${TMP_DIR}/fat.img"
+MNT_PATH="${TMP_DIR}/mnt"
+
+cleanup()
+{
+    mountpoint -q "${MNT_PATH}" && unmount_image
+    rm -rf "${TMP_DIR}"
+}
+trap cleanup SIGINT SIGTERM EXIT
+
+create_loopback()
+{
+    touch "${IMG_PATH}"
+    chattr +C "${IMG_PATH}" >/dev/null 2>&1 || true
+
+    truncate -s 1M "${IMG_PATH}"
+    mkfs.vfat "${IMG_PATH}" >/dev/null 2>&1
+}
+
+mount_image()
+{
+    mkdir -p "${MNT_PATH}"
+    sudo mount -o loop "${IMG_PATH}" "${MNT_PATH}"
+}
+
+rename_exchange_test()
+{
+    local rename_exchange="${BASE_DIR}/rename_exchange"
+    local old_path="${MNT_PATH}/old_file"
+    local new_path="${MNT_PATH}/new_file"
+
+    echo old | sudo tee "${old_path}" >/dev/null 2>&1
+    echo new | sudo tee "${new_path}" >/dev/null 2>&1
+    sudo "${rename_exchange}" "${old_path}" "${new_path}" >/dev/null 2>&1
+    sudo sync -f "${MNT_PATH}"
+    grep new "${old_path}" >/dev/null 2>&1
+    grep old "${new_path}" >/dev/null 2>&1
+}
+
+rename_exchange_subdir_test()
+{
+    local rename_exchange="${BASE_DIR}/rename_exchange"
+    local dir_path="${MNT_PATH}/subdir"
+    local old_path="${MNT_PATH}/old_file"
+    local new_path="${dir_path}/new_file"
+
+    sudo mkdir -p "${dir_path}"
+    echo old | sudo tee "${old_path}" >/dev/null 2>&1
+    echo new | sudo tee "${new_path}" >/dev/null 2>&1
+    sudo "${rename_exchange}" "${old_path}" "${new_path}" >/dev/null 2>&1
+    sudo sync -f "${MNT_PATH}"
+    grep new "${old_path}" >/dev/null 2>&1
+    grep old "${new_path}" >/dev/null 2>&1
+}
+
+unmount_image()
+{
+    sudo umount "${MNT_PATH}" &> /dev/null
+}
+
+create_loopback
+mount_image
+rename_exchange_test
+rename_exchange_subdir_test
+unmount_image
+
+exit 0

tools/testing/selftests/proc/proc-pid-vm.c

···
 }
 #endif
 
-static bool g_vsyscall = false;
+/*
+ * 0: vsyscall VMA doesn't exist	vsyscall=none
+ * 1: vsyscall VMA is r-xp		vsyscall=emulate
+ * 2: vsyscall VMA is --xp		vsyscall=xonly
+ */
+static int g_vsyscall;
+static const char *str_vsyscall;
 
-static const char str_vsyscall[] =
+static const char str_vsyscall_0[] = "";
+static const char str_vsyscall_1[] =
 "ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]\n";
+static const char str_vsyscall_2[] =
+"ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0                  [vsyscall]\n";
 
 #ifdef __x86_64__
 static void sigaction_SIGSEGV(int _, siginfo_t *__, void *___)
···
 }
 
 /*
- * vsyscall page can't be unmapped, probe it with memory load.
+ * vsyscall page can't be unmapped, probe it directly.
  */
 static void vsyscall(void)
 {
···
 		act.sa_sigaction = sigaction_SIGSEGV;
 		(void)sigaction(SIGSEGV, &act, NULL);
 
+		/* gettimeofday(NULL, NULL); */
+		asm volatile (
+			"call %P0"
+			:
+			: "i" (0xffffffffff600000), "D" (NULL), "S" (NULL)
+			: "rax", "rcx", "r11"
+		);
+		exit(0);
+	}
+	waitpid(pid, &wstatus, 0);
+	if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0) {
+		/* vsyscall page exists and is executable. */
+	} else {
+		/* vsyscall page doesn't exist. */
+		g_vsyscall = 0;
+		return;
+	}
+
+	pid = fork();
+	if (pid < 0) {
+		fprintf(stderr, "fork, errno %d\n", errno);
+		exit(1);
+	}
+	if (pid == 0) {
+		struct rlimit rlim = {0, 0};
+		(void)setrlimit(RLIMIT_CORE, &rlim);
+
+		/* Hide "segfault at ffffffffff600000" messages. */
+		struct sigaction act;
+		memset(&act, 0, sizeof(struct sigaction));
+		act.sa_flags = SA_SIGINFO;
+		act.sa_sigaction = sigaction_SIGSEGV;
+		(void)sigaction(SIGSEGV, &act, NULL);
+
 		*(volatile int *)0xffffffffff600000UL;
 		exit(0);
 	}
 	waitpid(pid, &wstatus, 0);
 	if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) == 0) {
-		g_vsyscall = true;
+		/* vsyscall page is readable and executable. */
+		g_vsyscall = 1;
+		return;
 	}
+
+	/* vsyscall page is executable but unreadable. */
+	g_vsyscall = 2;
 }
 
 int main(void)
···
 	int exec_fd;
 
 	vsyscall();
+	switch (g_vsyscall) {
+	case 0:
+		str_vsyscall = str_vsyscall_0;
+		break;
+	case 1:
+		str_vsyscall = str_vsyscall_1;
+		break;
+	case 2:
+		str_vsyscall = str_vsyscall_2;
+		break;
+	default:
+		abort();
+	}
 
 	atexit(ate);
 
···
 
 	/* Test /proc/$PID/maps */
 	{
-		const size_t len = strlen(buf0) + (g_vsyscall ? strlen(str_vsyscall) : 0);
+		const size_t len = strlen(buf0) + strlen(str_vsyscall);
 		char buf[256];
 		ssize_t rv;
 		int fd;
···
 		rv = read(fd, buf, sizeof(buf));
 		assert(rv == len);
 		assert(memcmp(buf, buf0, strlen(buf0)) == 0);
-		if (g_vsyscall) {
+		if (g_vsyscall > 0) {
 			assert(memcmp(buf + strlen(buf0), str_vsyscall, strlen(str_vsyscall)) == 0);
 		}
 	}
···
 			assert(memmem(buf, rv, S[i], strlen(S[i])));
 		}
 
-		if (g_vsyscall) {
+		if (g_vsyscall > 0) {
 			assert(memmem(buf, rv, str_vsyscall, strlen(str_vsyscall)));
 		}
 	}