Merge tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Some request-based DM core and DM multipath fixes and cleanups

 - Constify a few variables in DM core and DM integrity

 - Add bufio optimization and checksum failure accounting to DM
   integrity

 - Fix DM integrity to avoid checking integrity of failed reads

 - Fix DM integrity to use init_completion

 - A couple DM log-writes target fixes

 - Simplify DAX flushing by eliminating the unnecessary flush
   abstraction that was stood up for DM's use.

* tag 'for-4.14/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dax: remove the pmem_dax_ops->flush abstraction
  dm integrity: use init_completion instead of COMPLETION_INITIALIZER_ONSTACK
  dm integrity: make blk_integrity_profile structure const
  dm integrity: do not check integrity for failed read operations
  dm log writes: fix >512b sectorsize support
  dm log writes: don't use all the cpu while waiting to log blocks
  dm ioctl: constify ioctl lookup table
  dm: constify argument arrays
  dm integrity: count and display checksum failures
  dm integrity: optimize writing dm-bufio buffers that are partially changed
  dm rq: do not update rq partially in each ending bio
  dm rq: make dm-sq requeuing behavior consistent with dm-mq behavior
  dm mpath: complain about unsupported __multipath_map_bio() return values
  dm mpath: avoid that building with W=1 causes gcc 7 to complain about fall-through

23 files changed, 189 insertions, 167 deletions

diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 3600ff786646..557b93703532 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -201,8 +201,10 @@ static umode_t dax_visible(struct kobject *kobj, struct attribute *a, int n)
 	if (!dax_dev)
 		return 0;
 
-	if (a == &dev_attr_write_cache.attr && !dax_dev->ops->flush)
+#ifndef CONFIG_ARCH_HAS_PMEM_API
+	if (a == &dev_attr_write_cache.attr)
 		return 0;
+#endif
 	return a->mode;
 }
 
@@ -267,18 +269,23 @@ size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 }
 EXPORT_SYMBOL_GPL(dax_copy_from_iter);
 
-void dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
-		size_t size)
+#ifdef CONFIG_ARCH_HAS_PMEM_API
+void arch_wb_cache_pmem(void *addr, size_t size);
+void dax_flush(struct dax_device *dax_dev, void *addr, size_t size)
 {
-	if (!dax_alive(dax_dev))
+	if (unlikely(!dax_alive(dax_dev)))
 		return;
 
-	if (!test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags))
+	if (unlikely(!test_bit(DAXDEV_WRITE_CACHE, &dax_dev->flags)))
 		return;
 
-	if (dax_dev->ops->flush)
-		dax_dev->ops->flush(dax_dev, pgoff, addr, size);
+	arch_wb_cache_pmem(addr, size);
 }
+#else
+void dax_flush(struct dax_device *dax_dev, void *addr, size_t size)
+{
+}
+#endif
 EXPORT_SYMBOL_GPL(dax_flush);
 
 void dax_write_cache(struct dax_device *dax_dev, bool wc)
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 9601225e0ae9..d216a8f7bc22 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -64,6 +64,12 @@
 #define DM_BUFIO_BLOCK_SIZE_GFP_LIMIT	(PAGE_SIZE << (MAX_ORDER - 1))
 
 /*
+ * Align buffer writes to this boundary.
+ * Tests show that SSDs have the highest IOPS when using 4k writes.
+ */
+#define DM_BUFIO_WRITE_ALIGN		4096
+
+/*
  * dm_buffer->list_mode
  */
 #define LIST_CLEAN	0
@@ -149,6 +155,10 @@ struct dm_buffer {
 	blk_status_t write_error;
 	unsigned long state;
 	unsigned long last_accessed;
+	unsigned dirty_start;
+	unsigned dirty_end;
+	unsigned write_start;
+	unsigned write_end;
 	struct dm_bufio_client *c;
 	struct list_head write_list;
 	struct bio bio;
@@ -560,7 +570,7 @@ static void dmio_complete(unsigned long error, void *context)
 }
 
 static void use_dmio(struct dm_buffer *b, int rw, sector_t sector,
-		     unsigned n_sectors, bio_end_io_t *end_io)
+		     unsigned n_sectors, unsigned offset, bio_end_io_t *end_io)
 {
 	int r;
 	struct dm_io_request io_req = {
@@ -578,10 +588,10 @@ static void use_dmio(struct dm_buffer *b, int rw, sector_t sector,
 
 	if (b->data_mode != DATA_MODE_VMALLOC) {
 		io_req.mem.type = DM_IO_KMEM;
-		io_req.mem.ptr.addr = b->data;
+		io_req.mem.ptr.addr = (char *)b->data + offset;
 	} else {
 		io_req.mem.type = DM_IO_VMA;
-		io_req.mem.ptr.vma = b->data;
+		io_req.mem.ptr.vma = (char *)b->data + offset;
 	}
 
 	b->bio.bi_end_io = end_io;
@@ -609,10 +619,10 @@ static void inline_endio(struct bio *bio)
 }
 
 static void use_inline_bio(struct dm_buffer *b, int rw, sector_t sector,
-			   unsigned n_sectors, bio_end_io_t *end_io)
+			   unsigned n_sectors, unsigned offset, bio_end_io_t *end_io)
 {
 	char *ptr;
-	int len;
+	unsigned len;
 
 	bio_init(&b->bio, b->bio_vec, DM_BUFIO_INLINE_VECS);
 	b->bio.bi_iter.bi_sector = sector;
@@ -625,29 +635,20 @@ static void use_inline_bio(struct dm_buffer *b, int rw, sector_t sector,
 	b->bio.bi_private = end_io;
 	bio_set_op_attrs(&b->bio, rw, 0);
 
-	/*
-	 * We assume that if len >= PAGE_SIZE ptr is page-aligned.
-	 * If len < PAGE_SIZE the buffer doesn't cross page boundary.
-	 */
-	ptr = b->data;
+	ptr = (char *)b->data + offset;
 	len = n_sectors << SECTOR_SHIFT;
 
-	if (len >= PAGE_SIZE)
-		BUG_ON((unsigned long)ptr & (PAGE_SIZE - 1));
-	else
-		BUG_ON((unsigned long)ptr & (len - 1));
-
 	do {
-		if (!bio_add_page(&b->bio, virt_to_page(ptr),
-				  len < PAGE_SIZE ? len : PAGE_SIZE,
+		unsigned this_step = min((unsigned)(PAGE_SIZE - offset_in_page(ptr)), len);
+		if (!bio_add_page(&b->bio, virt_to_page(ptr), this_step,
 				  offset_in_page(ptr))) {
 			BUG_ON(b->c->block_size <= PAGE_SIZE);
-			use_dmio(b, rw, sector, n_sectors, end_io);
+			use_dmio(b, rw, sector, n_sectors, offset, end_io);
 			return;
 		}
 
-		len -= PAGE_SIZE;
-		ptr += PAGE_SIZE;
+		len -= this_step;
+		ptr += this_step;
 	} while (len > 0);
 
 	submit_bio(&b->bio);
@@ -657,18 +658,33 @@ static void submit_io(struct dm_buffer *b, int rw, bio_end_io_t *end_io)
 {
 	unsigned n_sectors;
 	sector_t sector;
-
-	if (rw == WRITE && b->c->write_callback)
-		b->c->write_callback(b);
+	unsigned offset, end;
 
 	sector = (b->block << b->c->sectors_per_block_bits) + b->c->start;
-	n_sectors = 1 << b->c->sectors_per_block_bits;
+
+	if (rw != WRITE) {
+		n_sectors = 1 << b->c->sectors_per_block_bits;
+		offset = 0;
+	} else {
+		if (b->c->write_callback)
+			b->c->write_callback(b);
+		offset = b->write_start;
+		end = b->write_end;
+		offset &= -DM_BUFIO_WRITE_ALIGN;
+		end += DM_BUFIO_WRITE_ALIGN - 1;
+		end &= -DM_BUFIO_WRITE_ALIGN;
+		if (unlikely(end > b->c->block_size))
+			end = b->c->block_size;
+
+		sector += offset >> SECTOR_SHIFT;
+		n_sectors = (end - offset) >> SECTOR_SHIFT;
+	}
 
 	if (n_sectors <= ((DM_BUFIO_INLINE_VECS * PAGE_SIZE) >> SECTOR_SHIFT) &&
 	    b->data_mode != DATA_MODE_VMALLOC)
-		use_inline_bio(b, rw, sector, n_sectors, end_io);
+		use_inline_bio(b, rw, sector, n_sectors, offset, end_io);
 	else
-		use_dmio(b, rw, sector, n_sectors, end_io);
+		use_dmio(b, rw, sector, n_sectors, offset, end_io);
 }
 
 /*----------------------------------------------------------------
@@ -720,6 +736,9 @@ static void __write_dirty_buffer(struct dm_buffer *b,
 	clear_bit(B_DIRTY, &b->state);
 	wait_on_bit_lock_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE);
 
+	b->write_start = b->dirty_start;
+	b->write_end = b->dirty_end;
+
 	if (!write_list)
 		submit_io(b, WRITE, write_endio);
 	else
@@ -1221,19 +1240,37 @@ void dm_bufio_release(struct dm_buffer *b)
 }
 EXPORT_SYMBOL_GPL(dm_bufio_release);
 
-void dm_bufio_mark_buffer_dirty(struct dm_buffer *b)
+void dm_bufio_mark_partial_buffer_dirty(struct dm_buffer *b,
+					unsigned start, unsigned end)
 {
 	struct dm_bufio_client *c = b->c;
 
+	BUG_ON(start >= end);
+	BUG_ON(end > b->c->block_size);
+
 	dm_bufio_lock(c);
 
 	BUG_ON(test_bit(B_READING, &b->state));
 
-	if (!test_and_set_bit(B_DIRTY, &b->state))
+	if (!test_and_set_bit(B_DIRTY, &b->state)) {
+		b->dirty_start = start;
+		b->dirty_end = end;
 		__relink_lru(b, LIST_DIRTY);
+	} else {
+		if (start < b->dirty_start)
+			b->dirty_start = start;
+		if (end > b->dirty_end)
+			b->dirty_end = end;
+	}
 
 	dm_bufio_unlock(c);
 }
+EXPORT_SYMBOL_GPL(dm_bufio_mark_partial_buffer_dirty);
+
+void dm_bufio_mark_buffer_dirty(struct dm_buffer *b)
+{
+	dm_bufio_mark_partial_buffer_dirty(b, 0, b->c->block_size);
+}
 EXPORT_SYMBOL_GPL(dm_bufio_mark_buffer_dirty);
 
 void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c)
@@ -1398,6 +1435,8 @@ retry:
 		wait_on_bit_io(&b->state, B_WRITING,
 			       TASK_UNINTERRUPTIBLE);
 		set_bit(B_DIRTY, &b->state);
+		b->dirty_start = 0;
+		b->dirty_end = c->block_size;
 		__unlink_buffer(b);
 		__link_buffer(b, new_block, LIST_DIRTY);
 	} else {
diff --git a/drivers/md/dm-bufio.h b/drivers/md/dm-bufio.h
index b6d8f53ec15b..be732d3f8611 100644
--- a/drivers/md/dm-bufio.h
+++ b/drivers/md/dm-bufio.h
@@ -94,6 +94,15 @@ void dm_bufio_release(struct dm_buffer *b);
 void dm_bufio_mark_buffer_dirty(struct dm_buffer *b);
 
 /*
+ * Mark a part of the buffer dirty.
+ *
+ * The specified part of the buffer is scheduled to be written. dm-bufio may
+ * write the specified part of the buffer or it may write a larger superset.
+ */
+void dm_bufio_mark_partial_buffer_dirty(struct dm_buffer *b,
+					unsigned start, unsigned end);
+
+/*
  * Initiate writing of dirty buffers, without waiting for completion.
  */
 void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c);
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index dcac25c2be7a..8785134c9f1f 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2306,7 +2306,7 @@ static void init_features(struct cache_features *cf)
 static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
 			  char **error)
 {
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 2, "Invalid number of cache feature arguments"},
 	};
 
@@ -2348,7 +2348,7 @@ static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
 static int parse_policy(struct cache_args *ca, struct dm_arg_set *as,
 			char **error)
 {
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 1024, "Invalid number of policy arguments"},
 	};
 
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 54aef8ed97db..a55ffd4f5933 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2529,7 +2529,7 @@ static int crypt_ctr_optional(struct dm_target *ti, unsigned int argc, char **ar
 {
 	struct crypt_config *cc = ti->private;
 	struct dm_arg_set as;
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 6, "Invalid number of feature args"},
 	};
 	unsigned int opt_params, val;
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index 7146c2d9762d..b82cb1ab1eaa 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -51,7 +51,7 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
 	unsigned argc;
 	const char *arg_name;
 
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 6, "Invalid number of feature args"},
 		{1, UINT_MAX, "Invalid corrupt bio byte"},
 		{0, 255, "Invalid corrupt value to write into bio byte (0-255)"},
@@ -178,7 +178,7 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
  */
 static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 {
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, UINT_MAX, "Invalid up interval"},
 		{0, UINT_MAX, "Invalid down interval"},
 	};
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 27c0f223f8ea..096fe9b66c50 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -225,6 +225,8 @@ struct dm_integrity_c {
 	struct alg_spec internal_hash_alg;
 	struct alg_spec journal_crypt_alg;
 	struct alg_spec journal_mac_alg;
+
+	atomic64_t number_of_mismatches;
 };
 
 struct dm_integrity_range {
@@ -298,7 +300,7 @@ static void __DEBUG_bytes(__u8 *bytes, size_t len, const char *msg, ...)
 /*
  * DM Integrity profile, protection is performed layer above (dm-crypt)
  */
-static struct blk_integrity_profile dm_integrity_profile = {
+static const struct blk_integrity_profile dm_integrity_profile = {
 	.name			= "DM-DIF-EXT-TAG",
 	.generate_fn		= NULL,
 	.verify_fn		= NULL,
@@ -310,6 +312,8 @@ static void dm_integrity_dtr(struct dm_target *ti);
 
 static void dm_integrity_io_error(struct dm_integrity_c *ic, const char *msg, int err)
 {
+	if (err == -EILSEQ)
+		atomic64_inc(&ic->number_of_mismatches);
 	if (!cmpxchg(&ic->failed, 0, err))
 		DMERR("Error on %s: %d", msg, err);
 }
@@ -770,13 +774,13 @@ static void write_journal(struct dm_integrity_c *ic, unsigned commit_start, unsi
 	unsigned i;
 
 	io_comp.ic = ic;
-	io_comp.comp = COMPLETION_INITIALIZER_ONSTACK(io_comp.comp);
+	init_completion(&io_comp.comp);
 
 	if (commit_start + commit_sections <= ic->journal_sections) {
 		io_comp.in_flight = (atomic_t)ATOMIC_INIT(1);
 		if (ic->journal_io) {
 			crypt_comp_1.ic = ic;
-			crypt_comp_1.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp_1.comp);
+			init_completion(&crypt_comp_1.comp);
 			crypt_comp_1.in_flight = (atomic_t)ATOMIC_INIT(0);
 			encrypt_journal(ic, true, commit_start, commit_sections, &crypt_comp_1);
 			wait_for_completion_io(&crypt_comp_1.comp);
@@ -792,18 +796,18 @@ static void write_journal(struct dm_integrity_c *ic, unsigned commit_start, unsi
 		to_end = ic->journal_sections - commit_start;
 		if (ic->journal_io) {
 			crypt_comp_1.ic = ic;
-			crypt_comp_1.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp_1.comp);
+			init_completion(&crypt_comp_1.comp);
 			crypt_comp_1.in_flight = (atomic_t)ATOMIC_INIT(0);
 			encrypt_journal(ic, true, commit_start, to_end, &crypt_comp_1);
 			if (try_wait_for_completion(&crypt_comp_1.comp)) {
 				rw_journal(ic, REQ_OP_WRITE, REQ_FUA, commit_start, to_end, &io_comp);
-				crypt_comp_1.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp_1.comp);
+				reinit_completion(&crypt_comp_1.comp);
 				crypt_comp_1.in_flight = (atomic_t)ATOMIC_INIT(0);
 				encrypt_journal(ic, true, 0, commit_sections - to_end, &crypt_comp_1);
 				wait_for_completion_io(&crypt_comp_1.comp);
 			} else {
 				crypt_comp_2.ic = ic;
-				crypt_comp_2.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp_2.comp);
+				init_completion(&crypt_comp_2.comp);
 				crypt_comp_2.in_flight = (atomic_t)ATOMIC_INIT(0);
 				encrypt_journal(ic, true, 0, commit_sections - to_end, &crypt_comp_2);
 				wait_for_completion_io(&crypt_comp_1.comp);
@@ -1041,7 +1045,7 @@ static int dm_integrity_rw_tag(struct dm_integrity_c *ic, unsigned char *tag, se
 			memcpy(tag, dp, to_copy);
 		} else if (op == TAG_WRITE) {
 			memcpy(dp, tag, to_copy);
-			dm_bufio_mark_buffer_dirty(b);
+			dm_bufio_mark_partial_buffer_dirty(b, *metadata_offset, *metadata_offset + to_copy);
 		} else  {
 			/* e.g.: op == TAG_CMP */
 			if (unlikely(memcmp(dp, tag, to_copy))) {
@@ -1275,6 +1279,7 @@ again:
 					DMERR("Checksum failed at sector 0x%llx",
 					      (unsigned long long)(sector - ((r + ic->tag_size - 1) / ic->tag_size)));
 					r = -EILSEQ;
+					atomic64_inc(&ic->number_of_mismatches);
 				}
 				if (likely(checksums != checksums_onstack))
 					kfree(checksums);
@@ -1676,7 +1681,7 @@ sleep:
 	dio->in_flight = (atomic_t)ATOMIC_INIT(2);
 
 	if (need_sync_io) {
-		read_comp = COMPLETION_INITIALIZER_ONSTACK(read_comp);
+		init_completion(&read_comp);
 		dio->completion = &read_comp;
 	} else
 		dio->completion = NULL;
@@ -1700,7 +1705,11 @@ sleep:
 
 	if (need_sync_io) {
 		wait_for_completion_io(&read_comp);
-		integrity_metadata(&dio->work);
+		if (likely(!bio->bi_status))
+			integrity_metadata(&dio->work);
+		else
+			dec_in_flight(dio);
+
 	} else {
 		INIT_WORK(&dio->work, integrity_metadata);
 		queue_work(ic->metadata_wq, &dio->work);
@@ -1834,7 +1843,7 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned write_start,
 
 	comp.ic = ic;
 	comp.in_flight = (atomic_t)ATOMIC_INIT(1);
-	comp.comp = COMPLETION_INITIALIZER_ONSTACK(comp.comp);
+	init_completion(&comp.comp);
 
 	i = write_start;
 	for (n = 0; n < write_sections; n++, i++, wraparound_section(ic, &i)) {
@@ -2061,7 +2070,7 @@ static void replay_journal(struct dm_integrity_c *ic)
 		if (ic->journal_io) {
 			struct journal_completion crypt_comp;
 			crypt_comp.ic = ic;
-			crypt_comp.comp = COMPLETION_INITIALIZER_ONSTACK(crypt_comp.comp);
+			init_completion(&crypt_comp.comp);
 			crypt_comp.in_flight = (atomic_t)ATOMIC_INIT(0);
 			encrypt_journal(ic, false, 0, ic->journal_sections, &crypt_comp);
 			wait_for_completion(&crypt_comp.comp);
@@ -2233,7 +2242,7 @@ static void dm_integrity_status(struct dm_target *ti, status_type_t type,
 
 	switch (type) {
 	case STATUSTYPE_INFO:
-		result[0] = '\0';
+		DMEMIT("%llu", (unsigned long long)atomic64_read(&ic->number_of_mismatches));
 		break;
 
 	case STATUSTYPE_TABLE: {
@@ -2634,7 +2643,7 @@ static int create_journal(struct dm_integrity_c *ic, char **error)
 			memset(iv, 0x00, ivsize);
 
 			skcipher_request_set_crypt(req, sg, sg, PAGE_SIZE * ic->journal_pages + sizeof ic->commit_ids, iv);
-			comp.comp = COMPLETION_INITIALIZER_ONSTACK(comp.comp);
+			init_completion(&comp.comp);
 			comp.in_flight = (atomic_t)ATOMIC_INIT(1);
 			if (do_crypt(true, req, &comp))
 				wait_for_completion(&comp.comp);
@@ -2691,7 +2700,7 @@ static int create_journal(struct dm_integrity_c *ic, char **error)
 
 				sg_init_one(&sg, crypt_data, crypt_len);
 				skcipher_request_set_crypt(req, &sg, &sg, crypt_len, iv);
-				comp.comp = COMPLETION_INITIALIZER_ONSTACK(comp.comp);
+				init_completion(&comp.comp);
 				comp.in_flight = (atomic_t)ATOMIC_INIT(1);
 				if (do_crypt(true, req, &comp))
 					wait_for_completion(&comp.comp);
@@ -2778,7 +2787,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	int r;
 	unsigned extra_args;
 	struct dm_arg_set as;
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 9, "Invalid number of feature args"},
 	};
 	unsigned journal_sectors, interleave_sectors, buffer_sectors, journal_watermark, sync_msec;
@@ -2806,6 +2815,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	bio_list_init(&ic->flush_bio_list);
 	init_waitqueue_head(&ic->copy_to_journal_wait);
 	init_completion(&ic->crypto_backoff);
+	atomic64_set(&ic->number_of_mismatches, 0);
 
 	r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &ic->dev);
 	if (r) {
@@ -3202,7 +3212,7 @@ static void dm_integrity_dtr(struct dm_target *ti)
 
 static struct target_type integrity_target = {
 	.name			= "integrity",
-	.version		= {1, 0, 0},
+	.version		= {1, 1, 0},
 	.module			= THIS_MODULE,
 	.features		= DM_TARGET_SINGLETON | DM_TARGET_INTEGRITY,
 	.ctr			= dm_integrity_ctr,
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index e06f0ef7d2ec..8756a6850431 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1629,7 +1629,7 @@ static int target_message(struct file *filp, struct dm_ioctl *param, size_t para
  *---------------------------------------------------------------*/
 static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags)
 {
-	static struct {
+	static const struct {
 		int cmd;
 		int flags;
 		ioctl_fn fn;
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 405eca206d67..d5f8eff7c11d 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -184,20 +184,6 @@ static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
 	return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
 }
 
-static void linear_dax_flush(struct dm_target *ti, pgoff_t pgoff, void *addr,
-		size_t size)
-{
-	struct linear_c *lc = ti->private;
-	struct block_device *bdev = lc->dev->bdev;
-	struct dax_device *dax_dev = lc->dev->dax_dev;
-	sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
-
-	dev_sector = linear_map_sector(ti, sector);
-	if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(size, PAGE_SIZE), &pgoff))
-		return;
-	dax_flush(dax_dev, pgoff, addr, size);
-}
-
 static struct target_type linear_target = {
 	.name   = "linear",
 	.version = {1, 4, 0},
@@ -212,7 +198,6 @@ static struct target_type linear_target = {
 	.iterate_devices = linear_iterate_devices,
 	.direct_access = linear_dax_direct_access,
 	.dax_copy_from_iter = linear_dax_copy_from_iter,
-	.dax_flush = linear_dax_flush,
 };
 
 int __init dm_linear_init(void)
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index 534a254eb977..8b80a9ce9ea9 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -100,6 +100,7 @@ struct log_writes_c {
 	struct dm_dev *logdev;
 	u64 logged_entries;
 	u32 sectorsize;
+	u32 sectorshift;
 	atomic_t io_blocks;
 	atomic_t pending_blocks;
 	sector_t next_sector;
@@ -128,6 +129,18 @@ struct per_bio_data {
 	struct pending_block *block;
 };
 
+static inline sector_t bio_to_dev_sectors(struct log_writes_c *lc,
+					  sector_t sectors)
+{
+	return sectors >> (lc->sectorshift - SECTOR_SHIFT);
+}
+
+static inline sector_t dev_to_bio_sectors(struct log_writes_c *lc,
+					  sector_t sectors)
+{
+	return sectors << (lc->sectorshift - SECTOR_SHIFT);
+}
+
 static void put_pending_block(struct log_writes_c *lc)
 {
 	if (atomic_dec_and_test(&lc->pending_blocks)) {
@@ -253,7 +266,7 @@ static int log_one_block(struct log_writes_c *lc,
 
 	if (!block->vec_cnt)
 		goto out;
-	sector++;
+	sector += dev_to_bio_sectors(lc, 1);
 
 	atomic_inc(&lc->io_blocks);
 	bio = bio_alloc(GFP_KERNEL, min(block->vec_cnt, BIO_MAX_PAGES));
@@ -354,10 +367,9 @@ static int log_writes_kthread(void *arg)
 				goto next;
 
 			sector = lc->next_sector;
-			if (block->flags & LOG_DISCARD_FLAG)
-				lc->next_sector++;
-			else
-				lc->next_sector += block->nr_sectors + 1;
+			if (!(block->flags & LOG_DISCARD_FLAG))
+				lc->next_sector += dev_to_bio_sectors(lc, block->nr_sectors);
+			lc->next_sector += dev_to_bio_sectors(lc, 1);
 
 			/*
 			 * Apparently the size of the device may not be known
@@ -399,7 +411,7 @@ next:
 		if (!try_to_freeze()) {
 			set_current_state(TASK_INTERRUPTIBLE);
 			if (!kthread_should_stop() &&
-			    !atomic_read(&lc->pending_blocks))
+			    list_empty(&lc->logging_blocks))
 				schedule();
 			__set_current_state(TASK_RUNNING);
 		}
@@ -435,7 +447,6 @@ static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	INIT_LIST_HEAD(&lc->unflushed_blocks);
 	INIT_LIST_HEAD(&lc->logging_blocks);
 	init_waitqueue_head(&lc->wait);
-	lc->sectorsize = 1 << SECTOR_SHIFT;
 	atomic_set(&lc->io_blocks, 0);
 	atomic_set(&lc->pending_blocks, 0);
 
@@ -455,6 +466,8 @@ static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad;
 	}
 
+	lc->sectorsize = bdev_logical_block_size(lc->dev->bdev);
+	lc->sectorshift = ilog2(lc->sectorsize);
 	lc->log_kthread = kthread_run(log_writes_kthread, lc, "log-write");
 	if (IS_ERR(lc->log_kthread)) {
 		ret = PTR_ERR(lc->log_kthread);
@@ -464,8 +477,12 @@ static int log_writes_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad;
 	}
 
-	/* We put the super at sector 0, start logging at sector 1 */
-	lc->next_sector = 1;
+	/*
+	 * next_sector is in 512b sectors to correspond to what bi_sector expects.
+	 * The super starts at sector 0, and the next_sector is the next logical
+	 * one based on the sectorsize of the device.
+	 */
+	lc->next_sector = lc->sectorsize >> SECTOR_SHIFT;
 	lc->logging_enabled = true;
 	lc->end_sector = logdev_last_sector(lc);
 	lc->device_supports_discard = true;
@@ -599,8 +616,8 @@ static int log_writes_map(struct dm_target *ti, struct bio *bio)
 	if (discard_bio)
 		block->flags |= LOG_DISCARD_FLAG;
 
-	block->sector = bio->bi_iter.bi_sector;
-	block->nr_sectors = bio_sectors(bio);
+	block->sector = bio_to_dev_sectors(lc, bio->bi_iter.bi_sector);
+	block->nr_sectors = bio_to_dev_sectors(lc, bio_sectors(bio));
 
 	/* We don't need the data, just submit */
 	if (discard_bio) {
@@ -767,9 +784,12 @@ static void log_writes_io_hints(struct dm_target *ti, struct queue_limits *limit
 
 	if (!q || !blk_queue_discard(q)) {
 		lc->device_supports_discard = false;
-		limits->discard_granularity = 1 << SECTOR_SHIFT;
+		limits->discard_granularity = lc->sectorsize;
 		limits->max_discard_sectors = (UINT_MAX >> SECTOR_SHIFT);
 	}
+	limits->logical_block_size = bdev_logical_block_size(lc->dev->bdev);
+	limits->physical_block_size = bdev_physical_block_size(lc->dev->bdev);
+	limits->io_min = limits->physical_block_size;
 }
 
 static struct target_type log_writes_target = {
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 96aedaac2c64..11f273d2f018 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -632,6 +632,10 @@ static void process_queued_bios(struct work_struct *work)
 		case DM_MAPIO_REMAPPED:
 			generic_make_request(bio);
 			break;
+		case 0:
+			break;
+		default:
+			WARN_ONCE(true, "__multipath_map_bio() returned %d\n", r);
 		}
 	}
 	blk_finish_plug(&plug);
@@ -698,7 +702,7 @@ static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg,
 	struct path_selector_type *pst;
 	unsigned ps_argc;
 
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 1024, "invalid number of path selector args"},
 	};
 
@@ -822,7 +826,7 @@ retain:
 static struct priority_group *parse_priority_group(struct dm_arg_set *as,
 						   struct multipath *m)
 {
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{1, 1024, "invalid number of paths"},
 		{0, 1024, "invalid number of selector args"}
 	};
@@ -898,7 +902,7 @@ static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m)
 	int ret;
 	struct dm_target *ti = m->ti;
 
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 1024, "invalid number of hardware handler args"},
 	};
 
@@ -950,7 +954,7 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
 	struct dm_target *ti = m->ti;
 	const char *arg_name;
 
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 8, "invalid number of feature args"},
 		{1, 50, "pg_init_retries must be between 1 and 50"},
 		{0, 60000, "pg_init_delay_msecs must be between 0 and 60000"},
@@ -1019,7 +1023,7 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m)
 static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv)
 {
 	/* target arguments */
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 1024, "invalid number of priority groups"},
 		{0, 1024, "invalid initial priority group number"},
 	};
@@ -1379,6 +1383,7 @@ static void pg_init_done(void *data, int errors)
 	case SCSI_DH_RETRY:
 		/* Wait before retrying. */
 		delay_retry = 1;
+		/* fall through */
 	case SCSI_DH_IMM_RETRY:
 	case SCSI_DH_RES_TEMP_UNAVAIL:
 		if (pg_init_limit_reached(m, pgpath))
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index c6ebc5b1e00e..eadfcfd106ff 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -117,9 +117,9 @@ static void end_clone_bio(struct bio *clone)
 	struct dm_rq_clone_bio_info *info =
 		container_of(clone, struct dm_rq_clone_bio_info, clone);
 	struct dm_rq_target_io *tio = info->tio;
-	struct bio *bio = info->orig;
 	unsigned int nr_bytes = info->orig->bi_iter.bi_size;
 	blk_status_t error = clone->bi_status;
+	bool is_last = !clone->bi_next;
 
 	bio_put(clone);
 
@@ -137,28 +137,23 @@ static void end_clone_bio(struct bio *clone)
 		 * when the request is completed.
 		 */
 		tio->error = error;
-		return;
+		goto exit;
 	}
 
 	/*
 	 * I/O for the bio successfully completed.
 	 * Notice the data completion to the upper layer.
 	 */
-
-	/*
-	 * bios are processed from the head of the list.
-	 * So the completing bio should always be rq->bio.
-	 * If it's not, something wrong is happening.
-	 */
-	if (tio->orig->bio != bio)
-		DMERR("bio completion is going in the middle of the request");
+	tio->completed += nr_bytes;
 
 	/*
 	 * Update the original request.
 	 * Do not use blk_end_request() here, because it may complete
 	 * the original request before the clone, and break the ordering.
 	 */
-	blk_update_request(tio->orig, BLK_STS_OK, nr_bytes);
+	if (is_last)
+ exit:
+		blk_update_request(tio->orig, BLK_STS_OK, tio->completed);
 }
 
 static struct dm_rq_target_io *tio_from_request(struct request *rq)
@@ -237,14 +232,14 @@ static void dm_end_request(struct request *clone, blk_status_t error)
 /*
  * Requeue the original request of a clone.
  */
-static void dm_old_requeue_request(struct request *rq)
+static void dm_old_requeue_request(struct request *rq, unsigned long delay_ms)
 {
 	struct request_queue *q = rq->q;
 	unsigned long flags;
 
 	spin_lock_irqsave(q->queue_lock, flags);
 	blk_requeue_request(q, rq);
-	blk_run_queue_async(q);
+	blk_delay_queue(q, delay_ms);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
@@ -270,6 +265,7 @@ static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_
 	struct mapped_device *md = tio->md;
 	struct request *rq = tio->orig;
 	int rw = rq_data_dir(rq);
+	unsigned long delay_ms = delay_requeue ? 100 : 0;
 
 	rq_end_stats(md, rq);
 	if (tio->clone) {
@@ -278,9 +274,9 @@ static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_
 	}
 
 	if (!rq->q->mq_ops)
-		dm_old_requeue_request(rq);
+		dm_old_requeue_request(rq, delay_ms);
 	else
-		dm_mq_delay_requeue_request(rq, delay_requeue ? 100/*ms*/ : 0);
+		dm_mq_delay_requeue_request(rq, delay_ms);
 
 	rq_completed(md, rw, false);
 }
@@ -455,6 +451,7 @@ static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
 	tio->clone = NULL;
 	tio->orig = rq;
 	tio->error = 0;
+	tio->completed = 0;
 	/*
 	 * Avoid initializing info for blk-mq; it passes
 	 * target-specific data through info.ptr
diff --git a/drivers/md/dm-rq.h b/drivers/md/dm-rq.h
index 9813922e4fe5..f43c45460aac 100644
--- a/drivers/md/dm-rq.h
+++ b/drivers/md/dm-rq.h
@@ -29,6 +29,7 @@ struct dm_rq_target_io {
 	struct dm_stats_aux stats_aux;
 	unsigned long duration_jiffies;
 	unsigned n_sectors;
+	unsigned completed;
 };
 
 /*
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index ab50d7c4377f..b5e892149c54 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -351,25 +351,6 @@ static size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
 	return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
 }
 
-static void stripe_dax_flush(struct dm_target *ti, pgoff_t pgoff, void *addr,
-		size_t size)
-{
-	sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
-	struct stripe_c *sc = ti->private;
-	struct dax_device *dax_dev;
-	struct block_device *bdev;
-	uint32_t stripe;
-
-	stripe_map_sector(sc, sector, &stripe, &dev_sector);
-	dev_sector += sc->stripe[stripe].physical_start;
-	dax_dev = sc->stripe[stripe].dev->dax_dev;
-	bdev = sc->stripe[stripe].dev->bdev;
-
-	if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(size, PAGE_SIZE), &pgoff))
-		return;
-	dax_flush(dax_dev, pgoff, addr, size);
-}
-
 /*
  * Stripe status:
  *
@@ -489,7 +470,6 @@ static struct target_type stripe_target = {
 	.io_hints = stripe_io_hints,
 	.direct_access = stripe_dax_direct_access,
 	.dax_copy_from_iter = stripe_dax_copy_from_iter,
-	.dax_flush = stripe_dax_flush,
 };
 
 int __init dm_stripe_init(void)
diff --git a/drivers/md/dm-switch.c b/drivers/md/dm-switch.c
index 2dcea4c56f37..4c8de1ff78ca 100644
--- a/drivers/md/dm-switch.c
+++ b/drivers/md/dm-switch.c
@@ -251,7 +251,7 @@ static void switch_dtr(struct dm_target *ti)
  */
 static int switch_ctr(struct dm_target *ti, unsigned argc, char **argv)
 {
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{1, (KMALLOC_MAX_SIZE - sizeof(struct switch_ctx)) / sizeof(struct switch_path), "Invalid number of paths"},
 		{1, UINT_MAX, "Invalid region size"},
 		{0, 0, "Invalid number of optional args"},
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 28a4071cdf85..ef7b8f201f73 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -806,7 +806,8 @@ int dm_table_add_target(struct dm_table *t, const char *type,
 /*
  * Target argument parsing helpers.
  */
-static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
+static int validate_next_arg(const struct dm_arg *arg,
+			     struct dm_arg_set *arg_set,
 			     unsigned *value, char **error, unsigned grouped)
 {
 	const char *arg_str = dm_shift_arg(arg_set);
@@ -824,14 +825,14 @@ static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 	return 0;
 }
 
-int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
+int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set,
 		unsigned *value, char **error)
 {
 	return validate_next_arg(arg, arg_set, value, error, 0);
 }
 EXPORT_SYMBOL(dm_read_arg);
 
-int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
+int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set,
 		      unsigned *value, char **error)
 {
 	return validate_next_arg(arg, arg_set, value, error, 1);
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 69d88aee3055..1e25705209c2 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -3041,7 +3041,7 @@ static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
 	unsigned argc;
 	const char *arg_name;
 
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, 4, "Invalid number of pool feature arguments"},
 	};
 
diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 1c5b6185c79d..bda3caca23ca 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -839,7 +839,7 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
 	struct dm_target *ti = v->ti;
 	const char *arg_name;
 
-	static struct dm_arg _args[] = {
+	static const struct dm_arg _args[] = {
 		{0, DM_VERITY_OPTS_MAX, "Invalid number of feature args"},
 	};
 
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 04ae795e8a5f..6e54145969c5 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -987,24 +987,6 @@ static size_t dm_dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
 	return ret;
 }
 
-static void dm_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
-		size_t size)
-{
-	struct mapped_device *md = dax_get_private(dax_dev);
-	sector_t sector = pgoff * PAGE_SECTORS;
-	struct dm_target *ti;
-	int srcu_idx;
-
-	ti = dm_dax_get_live_target(md, sector, &srcu_idx);
-
-	if (!ti)
-		goto out;
-	if (ti->type->dax_flush)
-		ti->type->dax_flush(ti, pgoff, addr, size);
- out:
-	dm_put_live_table(md, srcu_idx);
-}
-
 /*
  * A target may call dm_accept_partial_bio only from the map routine.  It is
  * allowed for all bio types except REQ_PREFLUSH.
@@ -2992,7 +2974,6 @@ static const struct block_device_operations dm_blk_dops = {
 static const struct dax_operations dm_dax_ops = {
 	.direct_access = dm_dax_direct_access,
 	.copy_from_iter = dm_dax_copy_from_iter,
-	.flush = dm_dax_flush,
 };
 
 /*
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index e9aa453da50c..39dfd7affa31 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -262,16 +262,9 @@ static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
 	return copy_from_iter_flushcache(addr, bytes, i);
 }
 
-static void pmem_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff,
-		void *addr, size_t size)
-{
-	arch_wb_cache_pmem(addr, size);
-}
-
 static const struct dax_operations pmem_dax_ops = {
 	.direct_access = pmem_dax_direct_access,
 	.copy_from_iter = pmem_copy_from_iter,
-	.flush = pmem_dax_flush,
 };
 
 static const struct attribute_group *pmem_attribute_groups[] = {
diff --git a/fs/dax.c b/fs/dax.c
index 6afcacb3a87b..f001d8c72a06 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -734,7 +734,7 @@ static int dax_writeback_one(struct block_device *bdev,
 	}
 
 	dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(pfn));
-	dax_flush(dax_dev, pgoff, kaddr, size);
+	dax_flush(dax_dev, kaddr, size);
 	/*
 	 * After we have flushed the cache, we can clear the dirty tag. There
 	 * cannot be new dirty data in the pfn after the flush has completed as
@@ -929,7 +929,7 @@ int __dax_zero_page_range(struct block_device *bdev,
 			return rc;
 		}
 		memset(kaddr + offset, 0, size);
-		dax_flush(dax_dev, pgoff, kaddr + offset, size);
+		dax_flush(dax_dev, kaddr + offset, size);
 		dax_read_unlock(id);
 	}
 	return 0;
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 46cad1d0f129..122197124b9d 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -19,8 +19,6 @@ struct dax_operations {
 	/* copy_from_iter: required operation for fs-dax direct-i/o */
 	size_t (*copy_from_iter)(struct dax_device *, pgoff_t, void *, size_t,
 			struct iov_iter *);
-	/* flush: optional driver-specific cache management after writes */
-	void (*flush)(struct dax_device *, pgoff_t, void *, size_t);
 };
 
 extern struct attribute_group dax_attribute_group;
@@ -90,8 +88,7 @@ long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
 		void **kaddr, pfn_t *pfn);
 size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
 		size_t bytes, struct iov_iter *i);
-void dax_flush(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
-		size_t size);
+void dax_flush(struct dax_device *dax_dev, void *addr, size_t size);
 void dax_write_cache(struct dax_device *dax_dev, bool wc);
 bool dax_write_cache_enabled(struct dax_device *dax_dev);
 
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 4f2b3b2076c4..a5538433c927 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -134,8 +134,6 @@ typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff,
 		long nr_pages, void **kaddr, pfn_t *pfn);
 typedef size_t (*dm_dax_copy_from_iter_fn)(struct dm_target *ti, pgoff_t pgoff,
 		void *addr, size_t bytes, struct iov_iter *i);
-typedef void (*dm_dax_flush_fn)(struct dm_target *ti, pgoff_t pgoff, void *addr,
-		size_t size);
 #define PAGE_SECTORS (PAGE_SIZE / 512)
 
 void dm_error(const char *message);
@@ -186,7 +184,6 @@ struct target_type {
 	dm_io_hints_fn io_hints;
 	dm_dax_direct_access_fn direct_access;
 	dm_dax_copy_from_iter_fn dax_copy_from_iter;
-	dm_dax_flush_fn dax_flush;
 
 	/* For internal device-mapper use. */
 	struct list_head list;
@@ -387,7 +384,7 @@ struct dm_arg {
  * Validate the next argument, either returning it as *value or, if invalid,
  * returning -EINVAL and setting *error.
  */
-int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
+int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set,
 		unsigned *value, char **error);
 
 /*
@@ -395,7 +392,7 @@ int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
  * arg->min and arg->max further arguments. Either return the size as
  * *num_args or, if invalid, return -EINVAL and set *error.
  */
-int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
+int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set,
 		      unsigned *num_args, char **error);
 
 /*