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 <t...@kernel.org>
Cc: Asai Thambi SP <asamymuth...@micron.com>
Cc: Stefan Haberland <s...@linux.vnet.ibm.com>
Cc: Jan Hoeppner <hoepp...@linux.vnet.ibm.com>
Cc: Bart Van Assche <bart.vanass...@wdc.com>
---
block/blk-mq.c | 2 +-
block/blk-mq.h | 2 --
block/blk-timeout.c | 13 +++++++++----
3 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 51e9704..b419746 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;
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..4f04cd1 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -156,12 +156,17 @@ 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);
+ /*
+ * 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);
}
--
2.9.5
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
