4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mike Snitzer <snitzer@xxxxxxxxxx>
[ Upstream commit 42c9cdfe1e11e083dceb0f0c4977b758cf7403b9 ]
Set max_discard_segments to USHRT_MAX in blk_set_stacking_limits() so
that blk_stack_limits() can stack up this limit for stacked devices.
before:
$ cat /sys/block/nvme0n1/queue/max_discard_segments
256
$ cat /sys/block/dm-0/queue/max_discard_segments
1
after:
$ cat /sys/block/nvme0n1/queue/max_discard_segments
256
$ cat /sys/block/dm-0/queue/max_discard_segments
256
Fixes: 1e739730c5b9e ("block: optionally merge discontiguous discard bios into a single request")
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-settings.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -128,7 +128,7 @@ void blk_set_stacking_limits(struct queu
/* Inherit limits from component devices */
lim->max_segments = USHRT_MAX;
- lim->max_discard_segments = 1;
+ lim->max_discard_segments = USHRT_MAX;
lim->max_hw_sectors = UINT_MAX;
lim->max_segment_size = UINT_MAX;
lim->max_sectors = UINT_MAX;
