dm: add support for REQ_NOWAIT and enable it for linear target
Add DM target feature flag DM_TARGET_NOWAIT which advertises that
target works with REQ_NOWAIT bios.
Add dm_table_supports_nowait() and update dm_table_set_restrictions()
to set/clear QUEUE_FLAG_NOWAIT accordingly.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index e1db434..00774b5 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -228,10 +228,11 @@ static struct target_type linear_target = {
.name = "linear",
.version = {1, 4, 0},
#ifdef CONFIG_BLK_DEV_ZONED
- .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_ZONED_HM,
+ .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
+ DM_TARGET_ZONED_HM,
.report_zones = linear_report_zones,
#else
- .features = DM_TARGET_PASSES_INTEGRITY,
+ .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT,
#endif
.module = THIS_MODULE,
.ctr = linear_ctr,
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 12d9090..07c319e 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1748,6 +1748,33 @@ static bool dm_table_supports_write_zeroes(struct dm_table *t)
return true;
}
+static int device_not_nowait_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_nowait(q);
+}
+
+static bool dm_table_supports_nowait(struct dm_table *t)
+{
+ struct dm_target *ti;
+ unsigned i = 0;
+
+ while (i < dm_table_get_num_targets(t)) {
+ ti = dm_table_get_target(t, i++);
+
+ if (!dm_target_supports_nowait(ti->type))
+ return false;
+
+ if (!ti->type->iterate_devices ||
+ ti->type->iterate_devices(ti, device_not_nowait_capable, NULL))
+ return false;
+ }
+
+ return true;
+}
+
static int device_not_discard_capable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
@@ -1850,6 +1877,11 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
*/
q->limits = *limits;
+ if (dm_table_supports_nowait(t))
+ blk_queue_flag_set(QUEUE_FLAG_NOWAIT, q);
+ else
+ blk_queue_flag_clear(QUEUE_FLAG_NOWAIT, q);
+
if (!dm_table_supports_discards(t)) {
blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q);
/* Must also clear discard limits... */
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3dedd9c..59b0687 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1802,7 +1802,9 @@ static blk_qc_t dm_submit_bio(struct bio *bio)
if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
dm_put_live_table(md, srcu_idx);
- if (!(bio->bi_opf & REQ_RAHEAD))
+ if (bio->bi_opf & REQ_NOWAIT)
+ bio_wouldblock_error(bio);
+ else if (!(bio->bi_opf & REQ_RAHEAD))
queue_io(md, bio);
else
bio_io_error(bio);
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 93096e5..d6f8d4b 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -252,6 +252,12 @@ struct target_type {
#define DM_TARGET_ZONED_HM 0x00000040
#define dm_target_supports_zoned_hm(type) ((type)->features & DM_TARGET_ZONED_HM)
+/*
+ * A target handles REQ_NOWAIT
+ */
+#define DM_TARGET_NOWAIT 0x00000080
+#define dm_target_supports_nowait(type) ((type)->features & DM_TARGET_NOWAIT)
+
struct dm_target {
struct dm_table *table;
struct target_type *type;
