* [PATCH 1/2] block: add QUEUE_FLAG_NOWAIT
2020-09-23 20:06 [PATCH 0/2] block/dm: add REQ_NOWAIT support for bio-based Mike Snitzer
@ 2020-09-23 20:06 ` Mike Snitzer
2020-09-24 13:40 ` Christoph Hellwig
2020-09-23 20:06 ` [PATCH 2/2] dm: add support for REQ_NOWAIT and enable it for linear target Mike Snitzer
2020-09-25 14:20 ` [PATCH 0/2] block/dm: add REQ_NOWAIT support for bio-based Jens Axboe
2 siblings, 1 reply; 5+ messages in thread
From: Mike Snitzer @ 2020-09-23 20:06 UTC (permalink / raw)
To: Jens Axboe; +Cc: Konstantin Khlebnikov, hch, dm-devel, linux-block
Add QUEUE_FLAG_NOWAIT to allow a block device to advertise support for
REQ_NOWAIT. Bio-based devices may set QUEUE_FLAG_NOWAIT where
applicable.
Update QUEUE_FLAG_MQ_DEFAULT to include QUEUE_FLAG_NOWAIT. Also
update submit_bio_checks() to verify it is set for REQ_NOWAIT bios.
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
block/blk-core.c | 4 ++--
include/linux/blkdev.h | 7 +++++--
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index ca3f0f00c943..e3adfa135a20 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -817,9 +817,9 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
/*
* For a REQ_NOWAIT based request, return -EOPNOTSUPP
- * if queue is not a request based queue.
+ * if queue does not support NOWAIT.
*/
- if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q))
+ if ((bio->bi_opf & REQ_NOWAIT) && !blk_queue_nowait(q))
goto not_supported;
if (should_fail_bio(bio))
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index be5ef6f4ba19..9723b497d435 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -618,10 +618,12 @@ struct request_queue {
#define QUEUE_FLAG_PCI_P2PDMA 25 /* device supports PCI p2p requests */
#define QUEUE_FLAG_ZONE_RESETALL 26 /* supports Zone Reset All */
#define QUEUE_FLAG_RQ_ALLOC_TIME 27 /* record rq->alloc_time_ns */
-#define QUEUE_FLAG_HCTX_ACTIVE 28 /* at least one blk-mq hctx is active */
+#define QUEUE_FLAG_HCTX_ACTIVE 28 /* at least one blk-mq hctx is active */
+#define QUEUE_FLAG_NOWAIT 29 /* device supports NOWAIT */
#define QUEUE_FLAG_MQ_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
- (1 << QUEUE_FLAG_SAME_COMP))
+ (1 << QUEUE_FLAG_SAME_COMP) | \
+ (1 << QUEUE_FLAG_NOWAIT))
void blk_queue_flag_set(unsigned int flag, struct request_queue *q);
void blk_queue_flag_clear(unsigned int flag, struct request_queue *q);
@@ -661,6 +663,7 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
#define blk_queue_pm_only(q) atomic_read(&(q)->pm_only)
#define blk_queue_fua(q) test_bit(QUEUE_FLAG_FUA, &(q)->queue_flags)
#define blk_queue_registered(q) test_bit(QUEUE_FLAG_REGISTERED, &(q)->queue_flags)
+#define blk_queue_nowait(q) test_bit(QUEUE_FLAG_NOWAIT, &(q)->queue_flags)
extern void blk_set_pm_only(struct request_queue *q);
extern void blk_clear_pm_only(struct request_queue *q);
--
2.15.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 2/2] dm: add support for REQ_NOWAIT and enable it for linear target
2020-09-23 20:06 [PATCH 0/2] block/dm: add REQ_NOWAIT support for bio-based Mike Snitzer
2020-09-23 20:06 ` [PATCH 1/2] block: add QUEUE_FLAG_NOWAIT Mike Snitzer
@ 2020-09-23 20:06 ` Mike Snitzer
2020-09-25 14:20 ` [PATCH 0/2] block/dm: add REQ_NOWAIT support for bio-based Jens Axboe
2 siblings, 0 replies; 5+ messages in thread
From: Mike Snitzer @ 2020-09-23 20:06 UTC (permalink / raw)
To: Jens Axboe; +Cc: Konstantin Khlebnikov, hch, dm-devel, linux-block
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
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>
---
drivers/md/dm-linear.c | 5 +++--
drivers/md/dm-table.c | 32 ++++++++++++++++++++++++++++++++
drivers/md/dm.c | 4 +++-
include/linux/device-mapper.h | 6 ++++++
4 files changed, 44 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index e1db43446327..00774b5d7668 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 acba92500c12..17fb9b96d18e 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1719,6 +1719,33 @@ 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)
{
@@ -1821,6 +1848,11 @@ 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 b110b5eb99a5..3ad4a8da8b15 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1733,7 +1733,9 @@ 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 57610fc3013e..ba3b0979e09f 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;
--
2.15.0
^ permalink raw reply related [flat|nested] 5+ messages in thread