Merge tag 'for-6.0/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Refactor DM core's mempool allocation so that it clearer by not being
   split acorss files.

 - Improve DM core's BLK_STS_DM_REQUEUE and BLK_STS_AGAIN handling.

 - Optimize DM core's more common bio splitting by eliminating the use
   of bio cloning with bio_split+bio_chain. Shift that cloning cost to
   the relatively unlikely dm_io requeue case that only occurs during
   error handling. Introduces dm_io_rewind() that will clone a bio that
   reflects the subset of the original bio that must be requeued.

 - Remove DM core's dm_table_get_num_targets() wrapper and audit all
   dm_table_get_target() callers.

 - Fix potential for OOM with DM writecache target by setting a default
   MAX_WRITEBACK_JOBS (set to 256MiB or 1/16 of total system memory,
   whichever is smaller).

 - Fix DM writecache target's stats that are reported through
   DM-specific table info.

 - Fix use-after-free crash in dm_sm_register_threshold_callback().

 - Refine DM core's Persistent Reservation handling in preparation for
   broader work Mike Christie is doing to add compatibility with
   Microsoft Windows Failover Cluster.

 - Fix various KASAN reported bugs in the DM raid target.

 - Fix DM raid target crash due to md_handle_request() bio splitting
   that recurses to block core without properly initializing the bio's
   bi_dev.

 - Fix some code comment typos and fix some Documentation formatting.

* tag 'for-6.0/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (29 commits)
  dm: fix dm-raid crash if md_handle_request() splits bio
  dm raid: fix address sanitizer warning in raid_resume
  dm raid: fix address sanitizer warning in raid_status
  dm: Start pr_preempt from the same starting path
  dm: Fix PR release handling for non All Registrants
  dm: Start pr_reserve from the same starting path
  dm: Allow dm_call_pr to be used for path searches
  dm: return early from dm_pr_call() if DM device is suspended
  dm thin: fix use-after-free crash in dm_sm_register_threshold_callback
  dm writecache: count number of blocks discarded, not number of discard bios
  dm writecache: count number of blocks written, not number of write bios
  dm writecache: count number of blocks read, not number of read bios
  dm writecache: return void from functions
  dm kcopyd: use __GFP_HIGHMEM when allocating pages
  dm writecache: set a default MAX_WRITEBACK_JOBS
  Documentation: dm writecache: Render status list as list
  Documentation: dm writecache: add blank line before optional parameters
  dm snapshot: fix typo in snapshot_map() comment
  dm raid: remove redundant "the" in parse_raid_params() comment
  dm cache: fix typo in 2 comment blocks
  ...

1 files changed, 146 insertions, 172 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index df904b7e95ce..332f96b58252 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -6,6 +6,7 @@
  */
 
 #include "dm-core.h"
+#include "dm-rq.h"
 
 #include <linux/module.h>
 #include <linux/vmalloc.h>
@@ -174,8 +175,6 @@ static void dm_table_destroy_crypto_profile(struct dm_table *t);
 
 void dm_table_destroy(struct dm_table *t)
 {
-	unsigned int i;
-
 	if (!t)
 		return;
 
@@ -184,13 +183,13 @@ void dm_table_destroy(struct dm_table *t)
 		kvfree(t->index[t->depth - 2]);
 
 	/* free the targets */
-	for (i = 0; i < t->num_targets; i++) {
-		struct dm_target *tgt = t->targets + i;
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
-		if (tgt->type->dtr)
-			tgt->type->dtr(tgt);
+		if (ti->type->dtr)
+			ti->type->dtr(ti);
 
-		dm_put_target_type(tgt->type);
+		dm_put_target_type(ti->type);
 	}
 
 	kvfree(t->highs);
@@ -450,14 +449,14 @@ EXPORT_SYMBOL(dm_put_device);
 /*
  * Checks to see if the target joins onto the end of the table.
  */
-static int adjoin(struct dm_table *table, struct dm_target *ti)
+static int adjoin(struct dm_table *t, struct dm_target *ti)
 {
 	struct dm_target *prev;
 
-	if (!table->num_targets)
+	if (!t->num_targets)
 		return !ti->begin;
 
-	prev = &table->targets[table->num_targets - 1];
+	prev = &t->targets[t->num_targets - 1];
 	return (ti->begin == (prev->begin + prev->len));
 }
 
@@ -564,8 +563,8 @@ int dm_split_args(int *argc, char ***argvp, char *input)
  * two or more targets, the size of each piece it gets split into must
  * be compatible with the logical_block_size of the target processing it.
  */
-static int validate_hardware_logical_block_alignment(struct dm_table *table,
-						 struct queue_limits *limits)
+static int validate_hardware_logical_block_alignment(struct dm_table *t,
+						     struct queue_limits *limits)
 {
 	/*
 	 * This function uses arithmetic modulo the logical_block_size
@@ -587,13 +586,13 @@ static int validate_hardware_logical_block_alignment(struct dm_table *table,
 
 	struct dm_target *ti;
 	struct queue_limits ti_limits;
-	unsigned i;
+	unsigned int i;
 
 	/*
 	 * Check each entry in the table in turn.
 	 */
-	for (i = 0; i < dm_table_get_num_targets(table); i++) {
-		ti = dm_table_get_target(table, i);
+	for (i = 0; i < t->num_targets; i++) {
+		ti = dm_table_get_target(t, i);
 
 		blk_set_stacking_limits(&ti_limits);
 
@@ -621,7 +620,7 @@ static int validate_hardware_logical_block_alignment(struct dm_table *table,
 	if (remaining) {
 		DMWARN("%s: table line %u (start sect %llu len %llu) "
 		       "not aligned to h/w logical block size %u",
-		       dm_device_name(table->md), i,
+		       dm_device_name(t->md), i,
 		       (unsigned long long) ti->begin,
 		       (unsigned long long) ti->len,
 		       limits->logical_block_size);
@@ -636,7 +635,7 @@ int dm_table_add_target(struct dm_table *t, const char *type,
 {
 	int r = -EINVAL, argc;
 	char **argv;
-	struct dm_target *tgt;
+	struct dm_target *ti;
 
 	if (t->singleton) {
 		DMERR("%s: target type %s must appear alone in table",
@@ -646,87 +645,87 @@ int dm_table_add_target(struct dm_table *t, const char *type,
 
 	BUG_ON(t->num_targets >= t->num_allocated);
 
-	tgt = t->targets + t->num_targets;
-	memset(tgt, 0, sizeof(*tgt));
+	ti = t->targets + t->num_targets;
+	memset(ti, 0, sizeof(*ti));
 
 	if (!len) {
 		DMERR("%s: zero-length target", dm_device_name(t->md));
 		return -EINVAL;
 	}
 
-	tgt->type = dm_get_target_type(type);
-	if (!tgt->type) {
+	ti->type = dm_get_target_type(type);
+	if (!ti->type) {
 		DMERR("%s: %s: unknown target type", dm_device_name(t->md), type);
 		return -EINVAL;
 	}
 
-	if (dm_target_needs_singleton(tgt->type)) {
+	if (dm_target_needs_singleton(ti->type)) {
 		if (t->num_targets) {
-			tgt->error = "singleton target type must appear alone in table";
+			ti->error = "singleton target type must appear alone in table";
 			goto bad;
 		}
 		t->singleton = true;
 	}
 
-	if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
-		tgt->error = "target type may not be included in a read-only table";
+	if (dm_target_always_writeable(ti->type) && !(t->mode & FMODE_WRITE)) {
+		ti->error = "target type may not be included in a read-only table";
 		goto bad;
 	}
 
 	if (t->immutable_target_type) {
-		if (t->immutable_target_type != tgt->type) {
-			tgt->error = "immutable target type cannot be mixed with other target types";
+		if (t->immutable_target_type != ti->type) {
+			ti->error = "immutable target type cannot be mixed with other target types";
 			goto bad;
 		}
-	} else if (dm_target_is_immutable(tgt->type)) {
+	} else if (dm_target_is_immutable(ti->type)) {
 		if (t->num_targets) {
-			tgt->error = "immutable target type cannot be mixed with other target types";
+			ti->error = "immutable target type cannot be mixed with other target types";
 			goto bad;
 		}
-		t->immutable_target_type = tgt->type;
+		t->immutable_target_type = ti->type;
 	}
 
-	if (dm_target_has_integrity(tgt->type))
+	if (dm_target_has_integrity(ti->type))
 		t->integrity_added = 1;
 
-	tgt->table = t;
-	tgt->begin = start;
-	tgt->len = len;
-	tgt->error = "Unknown error";
+	ti->table = t;
+	ti->begin = start;
+	ti->len = len;
+	ti->error = "Unknown error";
 
 	/*
 	 * Does this target adjoin the previous one ?
 	 */
-	if (!adjoin(t, tgt)) {
-		tgt->error = "Gap in table";
+	if (!adjoin(t, ti)) {
+		ti->error = "Gap in table";
 		goto bad;
 	}
 
 	r = dm_split_args(&argc, &argv, params);
 	if (r) {
-		tgt->error = "couldn't split parameters";
+		ti->error = "couldn't split parameters";
 		goto bad;
 	}
 
-	r = tgt->type->ctr(tgt, argc, argv);
+	r = ti->type->ctr(ti, argc, argv);
 	kfree(argv);
 	if (r)
 		goto bad;
 
-	t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
+	t->highs[t->num_targets++] = ti->begin + ti->len - 1;
 
-	if (!tgt->num_discard_bios && tgt->discards_supported)
+	if (!ti->num_discard_bios && ti->discards_supported)
 		DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
 		       dm_device_name(t->md), type);
 
-	if (tgt->limit_swap_bios && !static_key_enabled(&swap_bios_enabled.key))
+	if (ti->limit_swap_bios && !static_key_enabled(&swap_bios_enabled.key))
 		static_branch_enable(&swap_bios_enabled);
 
 	return 0;
 
  bad:
-	DMERR("%s: %s: %s (%pe)", dm_device_name(t->md), type, tgt->error, ERR_PTR(r));
-	dm_put_target_type(tgt->type);
+	DMERR("%s: %s: %s (%pe)", dm_device_name(t->md), type, ti->error, ERR_PTR(r));
+	dm_put_target_type(ti->type);
 	return r;
 }
 
@@ -825,14 +824,11 @@ static int device_not_dax_synchronous_capable(struct dm_target *ti, struct dm_de
 }
 
 static bool dm_table_supports_dax(struct dm_table *t,
-			   iterate_devices_callout_fn iterate_fn)
+				  iterate_devices_callout_fn iterate_fn)
 {
-	struct dm_target *ti;
-	unsigned i;
-
 	/* Ensure that all targets support DAX. */
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->type->direct_access)
 			return false;
@@ -860,9 +856,8 @@ static int device_is_rq_stackable(struct dm_target *ti, struct dm_dev *dev,
 
 static int dm_table_determine_type(struct dm_table *t)
 {
-	unsigned i;
 	unsigned bio_based = 0, request_based = 0, hybrid = 0;
-	struct dm_target *tgt;
+	struct dm_target *ti;
 	struct list_head *devices = dm_table_get_devices(t);
 	enum dm_queue_mode live_md_type = dm_get_md_type(t->md);
 
@@ -876,11 +871,11 @@ static int dm_table_determine_type(struct dm_table *t)
 		goto verify_rq_based;
 	}
 
-	for (i = 0; i < t->num_targets; i++) {
-		tgt = t->targets + i;
-		if (dm_target_hybrid(tgt))
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		ti = dm_table_get_target(t, i);
+		if (dm_target_hybrid(ti))
 			hybrid = 1;
-		else if (dm_target_request_based(tgt))
+		else if (dm_target_request_based(ti))
 			request_based = 1;
 		else
 			bio_based = 1;
@@ -942,18 +937,18 @@ verify_rq_based:
 		return 0;
 	}
 
-	tgt = dm_table_get_immutable_target(t);
-	if (!tgt) {
+	ti = dm_table_get_immutable_target(t);
+	if (!ti) {
 		DMERR("table load rejected: immutable target is required");
 		return -EINVAL;
-	} else if (tgt->max_io_len) {
+	} else if (ti->max_io_len) {
 		DMERR("table load rejected: immutable target that splits IO is not supported");
 		return -EINVAL;
 	}
 
 	/* Non-request-stackable devices can't be used for request-based dm */
-	if (!tgt->type->iterate_devices ||
-	    !tgt->type->iterate_devices(tgt, device_is_rq_stackable, NULL)) {
+	if (!ti->type->iterate_devices ||
+	    !ti->type->iterate_devices(ti, device_is_rq_stackable, NULL)) {
 		DMERR("table load rejected: including non-request-stackable devices");
 		return -EINVAL;
 	}
@@ -983,11 +978,9 @@ struct dm_target *dm_table_get_immutable_target(struct dm_table *t)
 
 struct dm_target *dm_table_get_wildcard_target(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i;
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
-		ti = dm_table_get_target(t, i);
 		if (dm_target_is_wildcard(ti->type))
 			return ti;
 	}
@@ -1010,32 +1003,56 @@ static bool dm_table_supports_poll(struct dm_table *t);
 static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
 {
 	enum dm_queue_mode type = dm_table_get_type(t);
-	unsigned per_io_data_size = 0;
-	unsigned min_pool_size = 0;
-	struct dm_target *ti;
-	unsigned i;
-	bool poll_supported = false;
+	unsigned int per_io_data_size = 0, front_pad, io_front_pad;
+	unsigned int min_pool_size = 0, pool_size;
+	struct dm_md_mempools *pools;
 
 	if (unlikely(type == DM_TYPE_NONE)) {
 		DMWARN("no table type is set, can't allocate mempools");
 		return -EINVAL;
 	}
 
-	if (__table_type_bio_based(type)) {
-		for (i = 0; i < t->num_targets; i++) {
-			ti = t->targets + i;
-			per_io_data_size = max(per_io_data_size, ti->per_io_data_size);
-			min_pool_size = max(min_pool_size, ti->num_flush_bios);
-		}
-		poll_supported = dm_table_supports_poll(t);
+	pools = kzalloc_node(sizeof(*pools), GFP_KERNEL, md->numa_node_id);
+	if (!pools)
+		return -ENOMEM;
+
+	if (type == DM_TYPE_REQUEST_BASED) {
+		pool_size = dm_get_reserved_rq_based_ios();
+		front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
+		goto init_bs;
 	}
 
-	t->mempools = dm_alloc_md_mempools(md, type, per_io_data_size, min_pool_size,
-					   t->integrity_supported, poll_supported);
-	if (!t->mempools)
-		return -ENOMEM;
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
+		per_io_data_size = max(per_io_data_size, ti->per_io_data_size);
+		min_pool_size = max(min_pool_size, ti->num_flush_bios);
+	}
+	pool_size = max(dm_get_reserved_bio_based_ios(), min_pool_size);
+	front_pad = roundup(per_io_data_size,
+		__alignof__(struct dm_target_io)) + DM_TARGET_IO_BIO_OFFSET;
+
+	io_front_pad = roundup(per_io_data_size,
+		__alignof__(struct dm_io)) + DM_IO_BIO_OFFSET;
+	if (bioset_init(&pools->io_bs, pool_size, io_front_pad,
+			dm_table_supports_poll(t) ? BIOSET_PERCPU_CACHE : 0))
+		goto out_free_pools;
+	if (t->integrity_supported &&
+	    bioset_integrity_create(&pools->io_bs, pool_size))
+		goto out_free_pools;
+init_bs:
+	if (bioset_init(&pools->bs, pool_size, front_pad, 0))
+		goto out_free_pools;
+	if (t->integrity_supported &&
+	    bioset_integrity_create(&pools->bs, pool_size))
+		goto out_free_pools;
+
+	t->mempools = pools;
 	return 0;
+
+out_free_pools:
+	dm_free_md_mempools(pools);
+	return -ENOMEM;
 }
 
 static int setup_indexes(struct dm_table *t)
@@ -1100,10 +1117,10 @@ static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t)
 	struct list_head *devices = dm_table_get_devices(t);
 	struct dm_dev_internal *dd = NULL;
 	struct gendisk *prev_disk = NULL, *template_disk = NULL;
-	unsigned i;
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+	for (unsigned int i = 0; i < t->num_targets; i++) {
 		struct dm_target *ti = dm_table_get_target(t, i);
+
 		if (!dm_target_passes_integrity(ti->type))
 			goto no_integrity;
 	}
@@ -1217,18 +1234,19 @@ static int dm_keyslot_evict(struct blk_crypto_profile *profile,
 	struct dm_keyslot_evict_args args = { key };
 	struct dm_table *t;
 	int srcu_idx;
-	int i;
-	struct dm_target *ti;
 
 	t = dm_get_live_table(md, &srcu_idx);
 	if (!t)
 		return 0;
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
-		ti = dm_table_get_target(t, i);
+
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+
 		if (!ti->type->iterate_devices)
 			continue;
 		ti->type->iterate_devices(ti, dm_keyslot_evict_callback, &args);
 	}
+
 	dm_put_live_table(md, srcu_idx);
 	return args.err;
 }
@@ -1277,7 +1295,6 @@ static int dm_table_construct_crypto_profile(struct dm_table *t)
 {
 	struct dm_crypto_profile *dmcp;
 	struct blk_crypto_profile *profile;
-	struct dm_target *ti;
 	unsigned int i;
 	bool empty_profile = true;
 
@@ -1293,8 +1310,8 @@ static int dm_table_construct_crypto_profile(struct dm_table *t)
 	memset(profile->modes_supported, 0xFF,
 	       sizeof(profile->modes_supported));
 
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
-		ti = dm_table_get_target(t, i);
+	for (i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!dm_target_passes_crypto(ti->type)) {
 			blk_crypto_intersect_capabilities(profile, NULL);
@@ -1444,14 +1461,6 @@ inline sector_t dm_table_get_size(struct dm_table *t)
 }
 EXPORT_SYMBOL(dm_table_get_size);
 
-struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
-{
-	if (index >= t->num_targets)
-		return NULL;
-
-	return t->targets + index;
-}
-
 /*
  * Search the btree for the correct target.
  *
@@ -1512,11 +1521,8 @@ static int device_not_poll_capable(struct dm_target *ti, struct dm_dev *dev,
 static bool dm_table_any_dev_attr(struct dm_table *t,
 				  iterate_devices_callout_fn func, void *data)
 {
-	struct dm_target *ti;
-	unsigned int i;
-
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (ti->type->iterate_devices &&
 		    ti->type->iterate_devices(ti, func, data))
@@ -1538,11 +1544,8 @@ static int count_device(struct dm_target *ti, struct dm_dev *dev,
 
 static bool dm_table_supports_poll(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i = 0;
-
-	while (i < dm_table_get_num_targets(t)) {
-		ti = dm_table_get_target(t, i++);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->type->iterate_devices ||
 		    ti->type->iterate_devices(ti, device_not_poll_capable, NULL))
@@ -1558,18 +1561,15 @@ static bool dm_table_supports_poll(struct dm_table *t)
  * Returns false if the result is unknown because a target doesn't
  * support iterate_devices.
  */
-bool dm_table_has_no_data_devices(struct dm_table *table)
+bool dm_table_has_no_data_devices(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i, num_devices;
-
-	for (i = 0; i < dm_table_get_num_targets(table); i++) {
-		ti = dm_table_get_target(table, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+		unsigned num_devices = 0;
 
 		if (!ti->type->iterate_devices)
 			return false;
 
-		num_devices = 0;
 		ti->type->iterate_devices(ti, count_device, &num_devices);
 		if (num_devices)
 			return false;
@@ -1597,11 +1597,8 @@ static int device_not_zoned_model(struct dm_target *ti, struct dm_dev *dev,
 static bool dm_table_supports_zoned_model(struct dm_table *t,
 					  enum blk_zoned_model zoned_model)
 {
-	struct dm_target *ti;
-	unsigned i;
-
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (dm_target_supports_zoned_hm(ti->type)) {
 			if (!ti->type->iterate_devices ||
@@ -1632,16 +1629,16 @@ static int device_not_matches_zone_sectors(struct dm_target *ti, struct dm_dev *
  * zone sectors, if the destination device is a zoned block device, it shall
  * have the specified zone_sectors.
  */
-static int validate_hardware_zoned_model(struct dm_table *table,
+static int validate_hardware_zoned_model(struct dm_table *t,
 					 enum blk_zoned_model zoned_model,
 					 unsigned int zone_sectors)
 {
 	if (zoned_model == BLK_ZONED_NONE)
 		return 0;
 
-	if (!dm_table_supports_zoned_model(table, zoned_model)) {
+	if (!dm_table_supports_zoned_model(t, zoned_model)) {
 		DMERR("%s: zoned model is not consistent across all devices",
-		      dm_device_name(table->md));
+		      dm_device_name(t->md));
 		return -EINVAL;
 	}
 
@@ -1649,9 +1646,9 @@ static int validate_hardware_zoned_model(struct dm_table *table,
 	if (!zone_sectors || !is_power_of_2(zone_sectors))
 		return -EINVAL;
 
-	if (dm_table_any_dev_attr(table, device_not_matches_zone_sectors, &zone_sectors)) {
+	if (dm_table_any_dev_attr(t, device_not_matches_zone_sectors, &zone_sectors)) {
 		DMERR("%s: zone sectors is not consistent across all zoned devices",
-		      dm_device_name(table->md));
+		      dm_device_name(t->md));
 		return -EINVAL;
 	}
 
@@ -1661,21 +1658,19 @@ static int validate_hardware_zoned_model(struct dm_table *table,
 /*
  * Establish the new table's queue_limits and validate them.
  */
-int dm_calculate_queue_limits(struct dm_table *table,
+int dm_calculate_queue_limits(struct dm_table *t,
 			      struct queue_limits *limits)
 {
-	struct dm_target *ti;
 	struct queue_limits ti_limits;
-	unsigned i;
 	enum blk_zoned_model zoned_model = BLK_ZONED_NONE;
 	unsigned int zone_sectors = 0;
 
 	blk_set_stacking_limits(limits);
 
-	for (i = 0; i < dm_table_get_num_targets(table); i++) {
-		blk_set_stacking_limits(&ti_limits);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
-		ti = dm_table_get_target(table, i);
+		blk_set_stacking_limits(&ti_limits);
 
 		if (!ti->type->iterate_devices)
 			goto combine_limits;
@@ -1716,7 +1711,7 @@ combine_limits:
 			DMWARN("%s: adding target device "
 			       "(start sect %llu len %llu) "
 			       "caused an alignment inconsistency",
-			       dm_device_name(table->md),
+			       dm_device_name(t->md),
 			       (unsigned long long) ti->begin,
 			       (unsigned long long) ti->len);
 	}
@@ -1736,10 +1731,10 @@ combine_limits:
 		zoned_model = limits->zoned;
 		zone_sectors = limits->chunk_sectors;
 	}
-	if (validate_hardware_zoned_model(table, zoned_model, zone_sectors))
+	if (validate_hardware_zoned_model(t, zoned_model, zone_sectors))
 		return -EINVAL;
 
-	return validate_hardware_logical_block_alignment(table, limits);
+	return validate_hardware_logical_block_alignment(t, limits);
 }
 
 /*
@@ -1783,17 +1778,14 @@ static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
 
 static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
 {
-	struct dm_target *ti;
-	unsigned i;
-
 	/*
 	 * Require at least one underlying device to support flushes.
 	 * t->devices includes internal dm devices such as mirror logs
 	 * so we need to use iterate_devices here, which targets
 	 * supporting flushes must provide.
 	 */
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->num_flush_bios)
 			continue;
@@ -1847,11 +1839,8 @@ static int device_not_write_zeroes_capable(struct dm_target *ti, struct dm_dev *
 
 static bool dm_table_supports_write_zeroes(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i = 0;
-
-	while (i < dm_table_get_num_targets(t)) {
-		ti = dm_table_get_target(t, i++);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->num_write_zeroes_bios)
 			return false;
@@ -1874,11 +1863,8 @@ static int device_not_nowait_capable(struct dm_target *ti, struct dm_dev *dev,
 
 static bool dm_table_supports_nowait(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i = 0;
-
-	while (i < dm_table_get_num_targets(t)) {
-		ti = dm_table_get_target(t, i++);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!dm_target_supports_nowait(ti->type))
 			return false;
@@ -1899,11 +1885,8 @@ static int device_not_discard_capable(struct dm_target *ti, struct dm_dev *dev,
 
 static bool dm_table_supports_discards(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned i;
-
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->num_discard_bios)
 			return false;
@@ -1931,11 +1914,8 @@ static int device_not_secure_erase_capable(struct dm_target *ti,
 
 static bool dm_table_supports_secure_erase(struct dm_table *t)
 {
-	struct dm_target *ti;
-	unsigned int i;
-
-	for (i = 0; i < dm_table_get_num_targets(t); i++) {
-		ti = dm_table_get_target(t, i);
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->num_secure_erase_bios)
 			return false;
@@ -2065,11 +2045,6 @@ int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	return 0;
 }
 
-unsigned int dm_table_get_num_targets(struct dm_table *t)
-{
-	return t->num_targets;
-}
-
 struct list_head *dm_table_get_devices(struct dm_table *t)
 {
 	return &t->devices;
@@ -2089,12 +2064,11 @@ enum suspend_mode {
 
 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
 {
-	int i = t->num_targets;
-	struct dm_target *ti = t->targets;
-
 	lockdep_assert_held(&t->md->suspend_lock);
 
-	while (i--) {
+	for (unsigned int i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = dm_table_get_target(t, i);
+
 		switch (mode) {
 		case PRESUSPEND:
 			if (ti->type->presuspend)
@@ -2109,7 +2083,6 @@ static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
 				ti->type->postsuspend(ti);
 			break;
 		}
-		ti++;
 	}
 }
 
@@ -2139,12 +2112,13 @@ void dm_table_postsuspend_targets(struct dm_table *t)
 
 int dm_table_resume_targets(struct dm_table *t)
 {
-	int i, r = 0;
+	unsigned int i;
+	int r = 0;
 
 	lockdep_assert_held(&t->md->suspend_lock);
 
 	for (i = 0; i < t->num_targets; i++) {
-		struct dm_target *ti = t->targets + i;
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (!ti->type->preresume)
 			continue;
@@ -2158,7 +2132,7 @@ int dm_table_resume_targets(struct dm_table *t)
 	}
 
 	for (i = 0; i < t->num_targets; i++) {
-		struct dm_target *ti = t->targets + i;
+		struct dm_target *ti = dm_table_get_target(t, i);
 
 		if (ti->type->resume)
 			ti->type->resume(ti);