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authorMikulas Patocka <mpatocka@redhat.com>2023-04-04 11:19:33 -0400
committerMike Snitzer <snitzer@kernel.org>2023-04-04 13:30:17 -0400
commit00065f925efb077ade3e7fea49150d798cf87d05 (patch)
tree3d94da4faa23e88ee7175947e5236bfa1c041f47 /drivers/md
parent85c938e8914f8f0e276b8e82d4f2e4bcab044e96 (diff)
dm zero: add discard support
Add zero_io_hints() and set discard limits so that the zero target advertises support for discards. The zero target will ignore discards. This is useful when the user combines dm-zero with other discard-supporting targets in the same table; without dm-zero support, discards would be disabled for the whole combined device. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Tested-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm-zero.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
index 2601cd520384..6215d8eb7e41 100644
--- a/drivers/md/dm-zero.c
+++ b/drivers/md/dm-zero.c
@@ -27,6 +27,7 @@ static int zero_ctr(struct dm_target *ti, unsigned int argc, char **argv)
* Silently drop discards, avoiding -EOPNOTSUPP.
*/
ti->num_discard_bios = 1;
+ ti->discards_supported = true;
return 0;
}
@@ -45,6 +46,7 @@ static int zero_map(struct dm_target *ti, struct bio *bio)
zero_fill_bio(bio);
break;
case REQ_OP_WRITE:
+ case REQ_OP_DISCARD:
/* writes get silently dropped */
break;
default:
@@ -57,13 +59,21 @@ static int zero_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_SUBMITTED;
}
+static void zero_io_hints(struct dm_target *ti, struct queue_limits *limits)
+{
+ limits->max_discard_sectors = UINT_MAX;
+ limits->max_hw_discard_sectors = UINT_MAX;
+ limits->discard_granularity = 512;
+}
+
static struct target_type zero_target = {
.name = "zero",
- .version = {1, 1, 0},
+ .version = {1, 2, 0},
.features = DM_TARGET_NOWAIT,
.module = THIS_MODULE,
.ctr = zero_ctr,
.map = zero_map,
+ .io_hints = zero_io_hints,
};
static int __init dm_zero_init(void)