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>
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 6427be7..4f04cd1 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -156,12 +156,17 @@
*/
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);
+ /*
+ * All we need to ensure is that timeout scan takes place
+ * immediately and that scan sees the new timeout value.
+ * No need for fancy synchronizations.
+ */
+ 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);
}