diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 33bb074d694120a209ebac11d5e7ef93a3f445a3..b8ac591aaaa7070bfbd6d32c20993fb9130961f8 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -974,7 +974,8 @@ static void __get_memory_limit(struct dm_bufio_client *c,
 		buffers = c->minimum_buffers;
 
 	*limit_buffers = buffers;
-	*threshold_buffers = buffers * DM_BUFIO_WRITEBACK_PERCENT / 100;
+	*threshold_buffers = mult_frac(buffers,
+				       DM_BUFIO_WRITEBACK_PERCENT, 100);
 }
 
 /*
@@ -1910,19 +1911,15 @@ static int __init dm_bufio_init(void)
 	memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches);
 	memset(&dm_bufio_cache_names, 0, sizeof dm_bufio_cache_names);
 
-	mem = (__u64)((totalram_pages - totalhigh_pages) *
-		      DM_BUFIO_MEMORY_PERCENT / 100) << PAGE_SHIFT;
+	mem = (__u64)mult_frac(totalram_pages - totalhigh_pages,
+			       DM_BUFIO_MEMORY_PERCENT, 100) << PAGE_SHIFT;
 
 	if (mem > ULONG_MAX)
 		mem = ULONG_MAX;
 
 #ifdef CONFIG_MMU
-	/*
-	 * Get the size of vmalloc space the same way as VMALLOC_TOTAL
-	 * in fs/proc/internal.h
-	 */
-	if (mem > (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100)
-		mem = (VMALLOC_END - VMALLOC_START) * DM_BUFIO_VMALLOC_PERCENT / 100;
+	if (mem > mult_frac(VMALLOC_TOTAL, DM_BUFIO_VMALLOC_PERCENT, 100))
+		mem = mult_frac(VMALLOC_TOTAL, DM_BUFIO_VMALLOC_PERCENT, 100);
 #endif
 
 	dm_bufio_default_cache_size = mem;
diff --git a/drivers/md/dm-era-target.c b/drivers/md/dm-era-target.c
index ba84b8d62cd00f00668006449c4d8f2b2c39b019..73a5c198113a6a95dd7c81e4471b433a5b53fe58 100644
--- a/drivers/md/dm-era-target.c
+++ b/drivers/md/dm-era-target.c
@@ -1513,7 +1513,6 @@ static int era_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	ti->flush_supported = true;
 
 	ti->num_discard_bios = 1;
-	ti->discards_supported = true;
 	era->callbacks.congested_fn = era_is_congested;
 	dm_table_add_target_callbacks(ti->table, &era->callbacks);
 
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 204606bef9e2a15d3a91bfeefb3ee5d479506ced..c8faa2b8584268f75a8177f39677b94edba55289 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -499,8 +499,6 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
 	if (IS_ERR(clone)) {
 		/* EBUSY, ENODEV or EWOULDBLOCK: requeue */
 		bool queue_dying = blk_queue_dying(q);
-		DMERR_LIMIT("blk_get_request() returned %ld%s - requeuing",
-			    PTR_ERR(clone), queue_dying ? " (path offline)" : "");
 		if (queue_dying) {
 			atomic_inc(&m->pg_init_in_progress);
 			activate_or_offline_path(pgpath);
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 366c625b9591f87493ca21643f517a14af13f898..6319d846e0adb8c264f98676f0c2ddb8e85bdbb7 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -2887,9 +2887,6 @@ static void configure_discard_support(struct raid_set *rs)
 	bool raid456;
 	struct dm_target *ti = rs->ti;
 
-	/* Assume discards not supported until after checks below. */
-	ti->discards_supported = false;
-
 	/*
 	 * XXX: RAID level 4,5,6 require zeroing for safety.
 	 */
@@ -2914,9 +2911,6 @@ static void configure_discard_support(struct raid_set *rs)
 		}
 	}
 
-	/* All RAID members properly support discards */
-	ti->discards_supported = true;
-
 	/*
 	 * RAID1 and RAID10 personalities require bio splitting,
 	 * RAID0/4/5/6 don't and process large discard bios properly.
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 433bd3f3014c9bd067215985cbee3c8589484b28..88130b5d95f909ead8441dec7f3fb5d80a7914c7 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1758,13 +1758,12 @@ static bool dm_table_supports_write_zeroes(struct dm_table *t)
 	return true;
 }
 
-
-static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
-				  sector_t start, sector_t len, void *data)
+static int device_not_discard_capable(struct dm_target *ti, struct dm_dev *dev,
+				      sector_t start, sector_t len, void *data)
 {
 	struct request_queue *q = bdev_get_queue(dev->bdev);
 
-	return q && blk_queue_discard(q);
+	return q && !blk_queue_discard(q);
 }
 
 static bool dm_table_supports_discards(struct dm_table *t)
@@ -1772,28 +1771,24 @@ static bool dm_table_supports_discards(struct dm_table *t)
 	struct dm_target *ti;
 	unsigned i;
 
-	/*
-	 * Unless any target used by the table set discards_supported,
-	 * require at least one underlying device to support discards.
-	 * t->devices includes internal dm devices such as mirror logs
-	 * so we need to use iterate_devices here, which targets
-	 * supporting discard selectively must provide.
-	 */
 	for (i = 0; i < dm_table_get_num_targets(t); i++) {
 		ti = dm_table_get_target(t, i);
 
 		if (!ti->num_discard_bios)
-			continue;
-
-		if (ti->discards_supported)
-			return true;
+			return false;
 
-		if (ti->type->iterate_devices &&
-		    ti->type->iterate_devices(ti, device_discard_capable, NULL))
-			return true;
+		/*
+		 * Either the target provides discard support (as implied by setting
+		 * 'discards_supported') or it relies on _all_ data devices having
+		 * discard support.
+		 */
+		if (!ti->discards_supported &&
+		    (!ti->type->iterate_devices ||
+		     ti->type->iterate_devices(ti, device_not_discard_capable, NULL)))
+			return false;
 	}
 
-	return false;
+	return true;
 }
 
 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
@@ -1806,9 +1801,15 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	 */
 	q->limits = *limits;
 
-	if (!dm_table_supports_discards(t))
+	if (!dm_table_supports_discards(t)) {
 		queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
-	else
+		/* Must also clear discard limits... */
+		q->limits.max_discard_sectors = 0;
+		q->limits.max_hw_discard_sectors = 0;
+		q->limits.discard_granularity = 0;
+		q->limits.discard_alignment = 0;
+		q->limits.discard_misaligned = 0;
+	} else
 		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 
 	if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) {