Merge tag 'for-4.15/dm-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull  more device mapper updates from Mike Snitzer:
 "Given your expected travel I figured I'd get these fixes to you sooner
  rather than later.

   - a DM multipath stable@ fix to silence an annoying error message
     that isn't _really_ an error

   - a DM core @stable fix for discard support that was enabled for an
     entire DM device despite only having partial support for discards
     due to a mix of discard capabilities across the underlying devices.

   - a couple other DM core discard fixes.

   - a DM bufio @stable fix that resolves a 32-bit overflow"

* tag 'for-4.15/dm-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm bufio: fix integer overflow when limiting maximum cache size
  dm: clear all discard attributes in queue_limits when discards are disabled
  dm: do not set 'discards_supported' in targets that do not need it
  dm: discard support requires all targets in a table support discards
  dm mpath: remove annoying message of 'blk_get_request() returned -11'

1 files changed, 22 insertions, 21 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 433bd3f3014c..88130b5d95f9 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))) {