blk-mq: make blk_abort_request() trigger timeout path

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.

v2: - Add comment explaining the lack of synchronization around
      ->deadline update as requested by Bart.

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>
Cc: Bart Van Assche <Bart.VanAssche@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 1 insertions, 1 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 50dda2ff0d85..90f6910a83f6 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -820,7 +820,7 @@ 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;