Merge tag 'for-4.17/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

- a stable fix for DM integrity to use kvfree

- fix for a 4.17-rc1 change to dm-bufio's buffer alignment

- fixes for a few sparse warnings

- remove VLA usage in DM mirror target

- improve DM thinp Documentation for the "read_only" feature

* tag 'for-4.17/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm thin: update Documentation to clarify when "read_only" is valid
dm mirror: remove VLA usage
dm: fix some sparse warnings and whitespace in dax methods
dm cache background tracker: fix sparse warning
dm bufio: fix buffer alignment
dm integrity: use kvfree for kvmalloc'd memory

Documentation/device-mapper/thin-provisioning.txt

···
 			   data device, but just remove the mapping.
 
       read_only: Don't allow any changes to be made to the pool
-		 metadata.
+		 metadata.  This mode is only available after the
+		 thin-pool has been created and first used in full
+		 read/write mode.  It cannot be specified on initial
+		 thin-pool creation.
 
       error_if_no_space: Error IOs, instead of queueing, if no space.
 

drivers/md/dm-bufio.c

···
 
 	if (block_size <= KMALLOC_MAX_SIZE &&
 	    (block_size < PAGE_SIZE || !is_power_of_2(block_size))) {
-		snprintf(slab_name, sizeof slab_name, "dm_bufio_cache-%u", c->block_size);
-		c->slab_cache = kmem_cache_create(slab_name, c->block_size, ARCH_KMALLOC_MINALIGN,
+		unsigned align = min(1U << __ffs(block_size), (unsigned)PAGE_SIZE);
+		snprintf(slab_name, sizeof slab_name, "dm_bufio_cache-%u", block_size);
+		c->slab_cache = kmem_cache_create(slab_name, block_size, align,
 						  SLAB_RECLAIM_ACCOUNT, NULL);
 		if (!c->slab_cache) {
 			r = -ENOMEM;

drivers/md/dm-cache-background-tracker.c

···
 		atomic_read(&b->pending_demotes) >= b->max_work;
 }
 
-struct bt_work *alloc_work(struct background_tracker *b)
+static struct bt_work *alloc_work(struct background_tracker *b)
 {
 	if (max_work_reached(b))
 		return NULL;

drivers/md/dm-integrity.c

···
 	unsigned i;
 	for (i = 0; i < ic->journal_sections; i++)
 		kvfree(sl[i]);
-	kfree(sl);
+	kvfree(sl);
 }
 
 static struct scatterlist **dm_integrity_alloc_journal_scatterlist(struct dm_integrity_c *ic, struct page_list *pl)

drivers/md/dm-raid1.c

···
 
 #define MAX_RECOVERY 1	/* Maximum number of regions recovered in parallel. */
 
+#define MAX_NR_MIRRORS	(DM_KCOPYD_MAX_REGIONS + 1)
+
 #define DM_RAID1_HANDLE_ERRORS	0x01
 #define DM_RAID1_KEEP_LOG	0x02
 #define errors_handled(p)	((p)->features & DM_RAID1_HANDLE_ERRORS)
···
 	unsigned long error_bits;
 
 	unsigned int i;
-	struct dm_io_region io[ms->nr_mirrors];
+	struct dm_io_region io[MAX_NR_MIRRORS];
 	struct mirror *m;
 	struct dm_io_request io_req = {
 		.bi_op = REQ_OP_WRITE,
···
 static void do_write(struct mirror_set *ms, struct bio *bio)
 {
 	unsigned int i;
-	struct dm_io_region io[ms->nr_mirrors], *dest = io;
+	struct dm_io_region io[MAX_NR_MIRRORS], *dest = io;
 	struct mirror *m;
 	struct dm_io_request io_req = {
 		.bi_op = REQ_OP_WRITE,
···
 	argc -= args_used;
 
 	if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 ||
-	    nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) {
+	    nr_mirrors < 2 || nr_mirrors > MAX_NR_MIRRORS) {
 		ti->error = "Invalid number of mirrors";
 		dm_dirty_log_destroy(dl);
 		return -EINVAL;
···
 	int num_feature_args = 0;
 	struct mirror_set *ms = (struct mirror_set *) ti->private;
 	struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
-	char buffer[ms->nr_mirrors + 1];
+	char buffer[MAX_NR_MIRRORS + 1];
 
 	switch (type) {
 	case STATUSTYPE_INFO:

drivers/md/dm.c

···
 EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
 
 static struct dm_target *dm_dax_get_live_target(struct mapped_device *md,
-		sector_t sector, int *srcu_idx)
+						sector_t sector, int *srcu_idx)
+	__acquires(md->io_barrier)
 {
 	struct dm_table *map;
 	struct dm_target *ti;
···
 }
 
 static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
-		long nr_pages, void **kaddr, pfn_t *pfn)
+				 long nr_pages, void **kaddr, pfn_t *pfn)
 {
 	struct mapped_device *md = dax_get_private(dax_dev);
 	sector_t sector = pgoff * PAGE_SECTORS;
···
 }
 
 static size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
-		void *addr, size_t bytes, struct iov_iter *i)
+				    void *addr, size_t bytes, struct iov_iter *i)
 {
 	struct mapped_device *md = dax_get_private(dax_dev);
 	sector_t sector = pgoff * PAGE_SECTORS;