diff options
| author | Arianna Avanzini <avanzini@google.com> | 2015-12-01 11:48:18 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-12-01 10:52:10 -0700 |
| commit | cf8ecc5a8455266f8d516426b2acd36f9bdfa061 (patch) | |
| tree | 81f99d356c0adb2f806782aa491097009c1616cc | |
| parent | 3c395a969acc690f331d5fb91ec99ea8eb5155dd (diff) | |
null_blk: guarantee device restart in all irq modes
In single-queue (block layer) mode,the function null_rq_prep_fn stops
the device if alloc_cmd fails. Then, once stopped, the device must be
restarted on the next command completion, so that the request(s) for
which alloc_cmd failed can be requeued. Otherwise the device hangs.
Unfortunately, device restart is currently performed only for delayed
completions, i.e., in irqmode==2. This fact causes hangs, for the
above reasons, with the other irqmodes in combination with single-queue
block layer.
This commits addresses this issue by making sure that, if stopped, the
device is properly restarted for all irqmodes on completions.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna AVanzini <avanzini@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
| -rw-r--r-- | drivers/block/null_blk.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index 08932f5ea9f3..cf656198836c 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -217,6 +217,8 @@ static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait) static void end_cmd(struct nullb_cmd *cmd) { + struct request_queue *q = NULL; + switch (queue_mode) { case NULL_Q_MQ: blk_mq_end_request(cmd->rq, 0); @@ -227,27 +229,28 @@ static void end_cmd(struct nullb_cmd *cmd) break; case NULL_Q_BIO: bio_endio(cmd->bio); - break; + goto free_cmd; } - free_cmd(cmd); -} - -static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer) -{ - struct nullb_cmd *cmd = container_of(timer, struct nullb_cmd, timer); - struct request_queue *q = NULL; - if (cmd->rq) q = cmd->rq->q; + /* Restart queue if needed, as we are freeing a tag */ if (q && !q->mq_ops && blk_queue_stopped(q)) { - spin_lock(q->queue_lock); + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); if (blk_queue_stopped(q)) blk_start_queue(q); - spin_unlock(q->queue_lock); + spin_unlock_irqrestore(q->queue_lock, flags); } - end_cmd(cmd); +free_cmd: + free_cmd(cmd); +} + +static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer) +{ + end_cmd(container_of(timer, struct nullb_cmd, timer)); return HRTIMER_NORESTART; } |