[PATCH v16 14/26] blk-mq: Restore the zoned write order when requeuing

Bart Van Assche
2024-11-19T00:28:58Z

Zoned writes may be requeued, e.g. if a block driver returns
BLK_STS_RESOURCE. Requests may be requeued in another order than
submitted. Restore the request order if requests are requeued.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
block/bfq-iosched.c | 2 ++
block/blk-mq.c | 20 +++++++++++++++++++-
block/blk-mq.h | 2 ++
block/kyber-iosched.c | 2 ++
block/mq-deadline.c | 7 ++++++-
include/linux/blk-mq.h | 2 +-
6 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 0747d9d0e48c..13bedbf03bd2 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -6265,6 +6265,8 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,

if (flags & BLK_MQ_INSERT_AT_HEAD) {
list_add(&rq->queuelist, &bfqd->dispatch);
+ } else if (flags & BLK_MQ_INSERT_ORDERED) {
+ blk_mq_insert_ordered(rq, &bfqd->dispatch);
} else if (!bfqq) {
list_add_tail(&rq->queuelist, &bfqd->dispatch);
} else {
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f134d5e1c4a1..1302ccbf2a7d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1564,7 +1564,9 @@ static void blk_mq_requeue_work(struct work_struct *work)
* already. Insert it into the hctx dispatch list to avoid
* block layer merges for the request.
*/
- if (rq->rq_flags & RQF_DONTPREP)
+ if (blk_rq_is_seq_zoned_write(rq))
+ blk_mq_insert_request(rq, BLK_MQ_INSERT_ORDERED);
+ else if (rq->rq_flags & RQF_DONTPREP)
blk_mq_request_bypass_insert(rq, 0);
else
blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD);
@@ -2599,6 +2601,20 @@ static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx,
blk_mq_run_hw_queue(hctx, run_queue_async);
}

+void blk_mq_insert_ordered(struct request *rq, struct list_head *list)
+{
+ struct request_queue *q = rq->q;
+ struct request *rq2;
+
+ list_for_each_entry(rq2, list, queuelist)
+ if (rq2->q == q && blk_rq_pos(rq2) > blk_rq_pos(rq))
+ break;
+
+ /* Insert rq before rq2. If rq2 is the list head, append at the end. */
+ list_add_tail(&rq->queuelist, &rq2->queuelist);
+}
+EXPORT_SYMBOL_GPL(blk_mq_insert_ordered);
+
static void blk_mq_insert_request(struct request *rq, blk_insert_t flags)
{
struct request_queue *q = rq->q;
@@ -2653,6 +2669,8 @@ static void blk_mq_insert_request(struct request *rq, blk_insert_t flags)
spin_lock(&ctx->lock);
if (flags & BLK_MQ_INSERT_AT_HEAD)
list_add(&rq->queuelist, &ctx->rq_lists[hctx->type]);
+ else if (flags & BLK_MQ_INSERT_ORDERED)
+ blk_mq_insert_ordered(rq, &ctx->rq_lists[hctx->type]);
else
list_add_tail(&rq->queuelist,
&ctx->rq_lists[hctx->type]);
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 309db553aba6..10b9fb3ca762 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -40,8 +40,10 @@ enum {

typedef unsigned int __bitwise blk_insert_t;
#define BLK_MQ_INSERT_AT_HEAD ((__force blk_insert_t)0x01)
+#define BLK_MQ_INSERT_ORDERED ((__force blk_insert_t)0x02)

void blk_mq_submit_bio(struct bio *bio);
+void blk_mq_insert_ordered(struct request *rq, struct list_head *list);
int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, struct io_comp_batch *iob,
unsigned int flags);
void blk_mq_exit_queue(struct request_queue *q);
diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c
index 4155594aefc6..77bb41bab68d 100644
--- a/block/kyber-iosched.c
+++ b/block/kyber-iosched.c
@@ -603,6 +603,8 @@ static void kyber_insert_requests(struct blk_mq_hw_ctx *hctx,
trace_block_rq_insert(rq);
if (flags & BLK_MQ_INSERT_AT_HEAD)
list_move(&rq->queuelist, head);
+ else if (flags & BLK_MQ_INSERT_ORDERED)
+ blk_mq_insert_ordered(rq, head);
else
list_move_tail(&rq->queuelist, head);
sbitmap_set_bit(&khd->kcq_map[sched_domain],
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 2edf84b1bc2a..200e5a2928ce 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -711,7 +711,12 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
* set expire time and add to fifo list
*/
rq->fifo_time = jiffies + dd->fifo_expire[data_dir];
- list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]);
+ if (flags & BLK_MQ_INSERT_ORDERED)
+ blk_mq_insert_ordered(rq,
+ &per_prio->fifo_list[data_dir]);
+ else
+ list_add_tail(&rq->queuelist,
+ &per_prio->fifo_list[data_dir]);
}
}

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index ac05974f08f9..f7514eefccfd 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -85,7 +85,7 @@ enum {

/* flags that prevent us from merging requests: */
#define RQF_NOMERGE_FLAGS \
- (RQF_STARTED | RQF_FLUSH_SEQ | RQF_SPECIAL_PAYLOAD)
+ (RQF_STARTED | RQF_FLUSH_SEQ | RQF_DONTPREP | RQF_SPECIAL_PAYLOAD)

enum mq_rq_state {
MQ_RQ_IDLE = 0,