[PATCH 4/7] blk-mq: make blk_abort_request() trigger timeout path

From: Tejun Heo
Date: Sat Dec 16 2017 - 07:07:56 EST

With issue/complete and timeout paths now using the generation number
and state based synchronization, blk_abort_request() is the only one
which depends on REQ_ATOM_COMPLETE for arbitrating completion.

There's no reason for blk_abort_request() to be a completely separate
path. This patch makes blk_abort_request() piggyback on the timeout
path instead of trying to terminate the request directly.

This removes the last dependency on REQ_ATOM_COMPLETE in blk-mq.

Note that this makes blk_abort_request() asynchronous - it initiates
abortion but the actual termination will happen after a short while,
even when the caller owns the request. AFAICS, SCSI and ATA should be
fine with that and I think mtip32xx and dasd should be safe but not
completely sure. It'd be great if people who know the drivers take a

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Asai Thambi SP <asamymuthupa@xxxxxxxxxx>
Cc: Stefan Haberland <sth@xxxxxxxxxxxxxxxxxx>
Cc: Jan Hoeppner <hoeppner@xxxxxxxxxxxxxxxxxx>
block/blk-mq.c | 2 +-
block/blk-mq.h | 2 --
block/blk-timeout.c | 8 ++++----
3 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 643a38d..88baa82 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -800,7 +800,7 @@ struct blk_mq_timeout_data {
unsigned int nr_expired;

-void blk_mq_rq_timed_out(struct request *req, bool reserved)
+static void blk_mq_rq_timed_out(struct request *req, bool reserved)
const struct blk_mq_ops *ops = req->q->mq_ops;
enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER;
diff --git a/block/blk-mq.h b/block/blk-mq.h
index cf01f6f..6b2d616 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -94,8 +94,6 @@ extern int blk_mq_sysfs_register(struct request_queue *q);
extern void blk_mq_sysfs_unregister(struct request_queue *q);
extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);

-extern void blk_mq_rq_timed_out(struct request *req, bool reserved);
void blk_mq_release(struct request_queue *q);

diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 6427be7..d580af3 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -156,12 +156,12 @@ void blk_timeout_work(struct work_struct *work)
void blk_abort_request(struct request *req)
- if (blk_mark_rq_complete(req))
- return;
if (req->q->mq_ops) {
- blk_mq_rq_timed_out(req, false);
+ req->deadline = jiffies;
+ mod_timer(&req->q->timeout, 0);
} else {
+ if (blk_mark_rq_complete(req))
+ return;