Merge tag 'folio-5.16b' of git://git.infradead.org/users/willy/pagecache

Pull folio fixes from Matthew Wilcox:
"In the course of preparing the folio changes for iomap for next merge
window, we discovered some problems that would be nice to address now:

- Renaming multi-page folios to large folios.

mapping_multi_page_folio_support() is just a little too long, so we
settled on mapping_large_folio_support(). That meant renaming, eg
folio_test_multi() to folio_test_large().

Rename AS_THP_SUPPORT to match

- I hadn't included folio wrappers for zero_user_segments(), etc.
Also, multi-page^W^W large folio support is now independent of
CONFIG_TRANSPARENT_HUGEPAGE, so machines with HIGHMEM always need
to fall back to the out-of-line zero_user_segments().

Remove FS_THP_SUPPORT to match

- The build bots finally got round to telling me that I missed a
couple of architectures when adding flush_dcache_folio(). Christoph
suggested that we just add linux/cacheflush.h and not rely on
asm-generic/cacheflush.h"

* tag 'folio-5.16b' of git://git.infradead.org/users/willy/pagecache:
mm: Add functions to zero portions of a folio
fs: Rename AS_THP_SUPPORT and mapping_thp_support
fs: Remove FS_THP_SUPPORT
mm: Remove folio_test_single
mm: Rename folio_test_multi to folio_test_large
Add linux/cacheflush.h

arch/arc/include/asm/cacheflush.h

···
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 
 void flush_dcache_page(struct page *page);
-void flush_dcache_folio(struct folio *folio);
 
 void dma_cache_wback_inv(phys_addr_t start, unsigned long sz);
 void dma_cache_inv(phys_addr_t start, unsigned long sz);

arch/arm/include/asm/cacheflush.h

···
  */
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 extern void flush_dcache_page(struct page *);
-void flush_dcache_folio(struct folio *folio);
 
 #define ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE 1
 static inline void flush_kernel_vmap_range(void *addr, int size)

arch/m68k/include/asm/cacheflush_mm.h

···
 
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 #define flush_dcache_page(page)		__flush_page_to_ram(page_address(page))
-void flush_dcache_folio(struct folio *folio);
 #define flush_dcache_mmap_lock(mapping)		do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)	do { } while (0)
 #define flush_icache_page(vma, page)	__flush_page_to_ram(page_address(page))

arch/mips/include/asm/cacheflush.h

···
 		SetPageDcacheDirty(page);
 }
 
-void flush_dcache_folio(struct folio *folio);
-
 #define flush_dcache_mmap_lock(mapping)		do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)	do { } while (0)
 

arch/nds32/include/asm/cacheflush.h

···
 
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 void flush_dcache_page(struct page *page);
-void flush_dcache_folio(struct folio *folio);
 void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
 		       unsigned long vaddr, void *dst, void *src, int len);
 void copy_from_user_page(struct vm_area_struct *vma, struct page *page,

arch/nios2/include/asm/cacheflush.h

···
 	unsigned long pfn);
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 void flush_dcache_page(struct page *page);
-void flush_dcache_folio(struct folio *folio);
 
 extern void flush_icache_range(unsigned long start, unsigned long end);
 extern void flush_icache_page(struct vm_area_struct *vma, struct page *page);

arch/parisc/include/asm/cacheflush.h

···
 
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 void flush_dcache_page(struct page *page);
-void flush_dcache_folio(struct folio *folio);
 
 #define flush_dcache_mmap_lock(mapping)		xa_lock_irq(&mapping->i_pages)
 #define flush_dcache_mmap_unlock(mapping)	xa_unlock_irq(&mapping->i_pages)

arch/sh/include/asm/cacheflush.h

···
 				 unsigned long start, unsigned long end);
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 void flush_dcache_page(struct page *page);
-void flush_dcache_folio(struct folio *folio);
 extern void flush_icache_range(unsigned long start, unsigned long end);
 #define flush_icache_user_range flush_icache_range
 extern void flush_icache_page(struct vm_area_struct *vma,

arch/xtensa/include/asm/cacheflush.h

···
 
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 void flush_dcache_page(struct page *);
-void flush_dcache_folio(struct folio *);
 
 void local_flush_cache_range(struct vm_area_struct *vma,
 		unsigned long start, unsigned long end);
···
 #define flush_cache_vunmap(start,end)			do { } while (0)
 
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
-#define ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO
 #define flush_dcache_page(page)				do { } while (0)
-static inline void flush_dcache_folio(struct folio *folio) { }
 
 #define flush_icache_range local_flush_icache_range
 #define flush_cache_page(vma, addr, pfn)		do { } while (0)

fs/inode.c

···
 	mapping->a_ops = &empty_aops;
 	mapping->host = inode;
 	mapping->flags = 0;
-	if (sb->s_type->fs_flags & FS_THP_SUPPORT)
-		__set_bit(AS_THP_SUPPORT, &mapping->flags);
 	mapping->wb_err = 0;
 	atomic_set(&mapping->i_mmap_writable, 0);
 #ifdef CONFIG_READ_ONLY_THP_FOR_FS

include/asm-generic/cacheflush.h

···
 {
 }
 
-static inline void flush_dcache_folio(struct folio *folio) { }
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
-#define ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO
-#endif
-
-#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO
-void flush_dcache_folio(struct folio *folio);
 #endif
 
 #ifndef flush_dcache_mmap_lock

include/linux/cacheflush.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_CACHEFLUSH_H
+#define _LINUX_CACHEFLUSH_H
+
+#include <asm/cacheflush.h>
+
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO
+void flush_dcache_folio(struct folio *folio);
+#endif
+#else
+static inline void flush_dcache_folio(struct folio *folio)
+{
+}
+#define ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO 0
+#endif /* ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE */
+
+#endif /* _LINUX_CACHEFLUSH_H */

include/linux/fs.h

···
 #define FS_USERNS_MOUNT		8	/* Can be mounted by userns root */
 #define FS_DISALLOW_NOTIFY_PERM	16	/* Disable fanotify permission events */
 #define FS_ALLOW_IDMAP         32      /* FS has been updated to handle vfs idmappings. */
-#define FS_THP_SUPPORT		8192	/* Remove once all fs converted */
 #define FS_RENAME_DOES_D_MOVE	32768	/* FS will handle d_move() during rename() internally. */
 	int (*init_fs_context)(struct fs_context *);
 	const struct fs_parameter_spec *parameters;

include/linux/highmem.h

···
 #include <linux/fs.h>
 #include <linux/kernel.h>
 #include <linux/bug.h>
+#include <linux/cacheflush.h>
 #include <linux/mm.h>
 #include <linux/uaccess.h>
 #include <linux/hardirq.h>
-
-#include <asm/cacheflush.h>
 
 #include "highmem-internal.h"
 
···
  * If we pass in a base or tail page, we can zero up to PAGE_SIZE.
  * If we pass in a head page, we can zero up to the size of the compound page.
  */
-#if defined(CONFIG_HIGHMEM) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
+#ifdef CONFIG_HIGHMEM
 void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
 		unsigned start2, unsigned end2);
-#else /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */
+#else
 static inline void zero_user_segments(struct page *page,
 		unsigned start1, unsigned end1,
 		unsigned start2, unsigned end2)
···
 	for (i = 0; i < compound_nr(page); i++)
 		flush_dcache_page(page + i);
 }
-#endif /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */
+#endif
 
 static inline void zero_user_segment(struct page *page,
 	unsigned start, unsigned end)
···
 	memset(addr + offset, 0, len);
 	flush_dcache_page(page);
 	kunmap_local(addr);
+}
+
+/**
+ * folio_zero_segments() - Zero two byte ranges in a folio.
+ * @folio: The folio to write to.
+ * @start1: The first byte to zero.
+ * @xend1: One more than the last byte in the first range.
+ * @start2: The first byte to zero in the second range.
+ * @xend2: One more than the last byte in the second range.
+ */
+static inline void folio_zero_segments(struct folio *folio,
+		size_t start1, size_t xend1, size_t start2, size_t xend2)
+{
+	zero_user_segments(&folio->page, start1, xend1, start2, xend2);
+}
+
+/**
+ * folio_zero_segment() - Zero a byte range in a folio.
+ * @folio: The folio to write to.
+ * @start: The first byte to zero.
+ * @xend: One more than the last byte to zero.
+ */
+static inline void folio_zero_segment(struct folio *folio,
+		size_t start, size_t xend)
+{
+	zero_user_segments(&folio->page, start, xend, 0, 0);
+}
+
+/**
+ * folio_zero_range() - Zero a byte range in a folio.
+ * @folio: The folio to write to.
+ * @start: The first byte to zero.
+ * @length: The number of bytes to zero.
+ */
+static inline void folio_zero_range(struct folio *folio,
+		size_t start, size_t length)
+{
+	zero_user_segments(&folio->page, start, start + length, 0, 0);
 }
 
 #endif /* _LINUX_HIGHMEM_H */

include/linux/page-flags.h

···
 
 __PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
 
-/* Whether there are one or multiple pages in a folio */
-static inline bool folio_test_single(struct folio *folio)
-{
-	return !folio_test_head(folio);
-}
-
-static inline bool folio_test_multi(struct folio *folio)
+/**
+ * folio_test_large() - Does this folio contain more than one page?
+ * @folio: The folio to test.
+ *
+ * Return: True if the folio is larger than one page.
+ */
+static inline bool folio_test_large(struct folio *folio)
 {
 	return folio_test_head(folio);
 }

include/linux/pagemap.h

···
 	AS_EXITING	= 4, 	/* final truncate in progress */
 	/* writeback related tags are not used */
 	AS_NO_WRITEBACK_TAGS = 5,
-	AS_THP_SUPPORT = 6,	/* THPs supported */
+	AS_LARGE_FOLIO_SUPPORT = 6,
 };
 
 /**
···
 	m->gfp_mask = mask;
 }
 
-static inline bool mapping_thp_support(struct address_space *mapping)
+/**
+ * mapping_set_large_folios() - Indicate the file supports large folios.
+ * @mapping: The file.
+ *
+ * The filesystem should call this function in its inode constructor to
+ * indicate that the VFS can use large folios to cache the contents of
+ * the file.
+ *
+ * Context: This should not be called while the inode is active as it
+ * is non-atomic.
+ */
+static inline void mapping_set_large_folios(struct address_space *mapping)
 {
-	return test_bit(AS_THP_SUPPORT, &mapping->flags);
+	__set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
+}
+
+static inline bool mapping_large_folio_support(struct address_space *mapping)
+{
+	return test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
 }
 
 static inline int filemap_nr_thps(struct address_space *mapping)
···
 static inline void filemap_nr_thps_inc(struct address_space *mapping)
 {
 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
-	if (!mapping_thp_support(mapping))
+	if (!mapping_large_folio_support(mapping))
 		atomic_inc(&mapping->nr_thps);
 #else
 	WARN_ON_ONCE(1);
···
 static inline void filemap_nr_thps_dec(struct address_space *mapping)
 {
 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
-	if (!mapping_thp_support(mapping))
+	if (!mapping_large_folio_support(mapping))
 		atomic_dec(&mapping->nr_thps);
 #else
 	WARN_ON_ONCE(1);

mm/highmem.c

···
 }
 EXPORT_SYMBOL(kunmap_high);
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
 		unsigned start2, unsigned end2)
 {
···
 	BUG_ON((start1 | start2 | end1 | end2) != 0);
 }
 EXPORT_SYMBOL(zero_user_segments);
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif /* CONFIG_HIGHMEM */
 
 #ifdef CONFIG_KMAP_LOCAL

mm/memcontrol.c

···
 
 	VM_BUG_ON(from == to);
 	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
-	VM_BUG_ON(compound && !folio_test_multi(folio));
+	VM_BUG_ON(compound && !folio_test_large(folio));
 
 	/*
 	 * Prevent mem_cgroup_migrate() from looking at

mm/shmem.c

···
 		INIT_LIST_HEAD(&info->swaplist);
 		simple_xattrs_init(&info->xattrs);
 		cache_no_acl(inode);
+		mapping_set_large_folios(inode->i_mapping);
 
 		switch (mode & S_IFMT) {
 		default:
···
 	.parameters	= shmem_fs_parameters,
 #endif
 	.kill_sb	= kill_litter_super,
-	.fs_flags	= FS_USERNS_MOUNT | FS_THP_SUPPORT,
+	.fs_flags	= FS_USERNS_MOUNT,
 };
 
 int __init shmem_init(void)

mm/util.c

···
 {
 	long i, nr;
 
-	if (folio_test_single(folio))
+	if (!folio_test_large(folio))
 		return atomic_read(&folio->_mapcount) >= 0;
 	if (atomic_read(folio_mapcount_ptr(folio)) >= 0)
 		return true;