| Message ID | 20180108191542.379478-6-tj@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 2018-01-08 at 11:15 -0800, Tejun Heo wrote: > @@ -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; > blk_delete_timer(req); > blk_rq_timed_out(req); > } Other req->deadline writes are protected by preempt_disable(), write_seqcount_begin(&rq->gstate_seq), write_seqcount_end(&rq->gstate_seq) and preempt_enable(). I think it's fine that the above req->deadline store does not have that protection but I also think that that deserves a comment. Thanks, Bart.
On Mon, Jan 08, 2018 at 10:10:01PM +0000, Bart Van Assche wrote: > Other req->deadline writes are protected by preempt_disable(), > write_seqcount_begin(&rq->gstate_seq), write_seqcount_end(&rq->gstate_seq) > and preempt_enable(). I think it's fine that the above req->deadline store > does not have that protection but I also think that that deserves a comment. Will add. Thanks.
diff --git a/block/blk-mq.c b/block/blk-mq.c index 41bfd27..bed4cb8 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -814,7 +814,7 @@ 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; blk_delete_timer(req); blk_rq_timed_out(req); }
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 look. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Asai Thambi SP <asamymuthupa@micron.com> Cc: Stefan Haberland <sth@linux.vnet.ibm.com> Cc: Jan Hoeppner <hoeppner@linux.vnet.ibm.com> --- block/blk-mq.c | 2 +- block/blk-mq.h | 2 -- block/blk-timeout.c | 8 ++++---- 3 files changed, 5 insertions(+), 7 deletions(-)