dm-integrity: set discard_granularity to logical block size

dm-integrity could set discard_granularity lower than the logical block
size. This could result in failures when sending discard requests to
dm-integrity.

This fix is needed for kernels prior to 6.10.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-by: Eric Wheeler <linux-integrity@lists.ewheeler.net>
Cc: stable@vger.kernel.org # <= 6.9
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

drivers/md/dm-integrity.c

@@ -3492,6 +3492,7 @@ static void dm_integrity_io_hints(struct dm_target *ti, struct queue_limits *lim
 		limits->physical_block_size = ic->sectors_per_block << SECTOR_SHIFT;
 		blk_limits_io_min(limits, ic->sectors_per_block << SECTOR_SHIFT);
 		limits->dma_alignment = limits->logical_block_size - 1;
+		limits->discard_granularity = ic->sectors_per_block << SECTOR_SHIFT;
 	}
 	limits->max_integrity_segments = USHRT_MAX;
 }