Commit 287922eb authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe

block: defer timeouts to a workqueue

Timer context is not very useful for drivers to perform any meaningful abort
action from.  So instead of calling the driver from this useless context
defer it to a workqueue as soon as possible.

Note that while a delayed_work item would seem the right thing here I didn't
dare to use it due to the magic in blk_add_timer that pokes deep into timer
internals.  But maybe this encourages Tejun to add a sensible API for that to
the workqueue API and we'll all be fine in the end :)

Contains a major update from Keith Bush:

"This patch removes synchronizing the timeout work so that the timer can
 start a freeze on its own queue. The timer enters the queue, so timer
 context can only start a freeze, but not wait for frozen."
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarKeith Busch <keith.busch@intel.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 8c0b3915
...@@ -664,6 +664,13 @@ static void blk_queue_usage_counter_release(struct percpu_ref *ref) ...@@ -664,6 +664,13 @@ static void blk_queue_usage_counter_release(struct percpu_ref *ref)
wake_up_all(&q->mq_freeze_wq); wake_up_all(&q->mq_freeze_wq);
} }
static void blk_rq_timed_out_timer(unsigned long data)
{
struct request_queue *q = (struct request_queue *)data;
kblockd_schedule_work(&q->timeout_work);
}
struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
{ {
struct request_queue *q; struct request_queue *q;
...@@ -825,6 +832,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn, ...@@ -825,6 +832,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
if (blk_init_rl(&q->root_rl, q, GFP_KERNEL)) if (blk_init_rl(&q->root_rl, q, GFP_KERNEL))
goto fail; goto fail;
INIT_WORK(&q->timeout_work, blk_timeout_work);
q->request_fn = rfn; q->request_fn = rfn;
q->prep_rq_fn = NULL; q->prep_rq_fn = NULL;
q->unprep_rq_fn = NULL; q->unprep_rq_fn = NULL;
......
...@@ -615,15 +615,19 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, ...@@ -615,15 +615,19 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
} }
} }
static void blk_mq_rq_timer(unsigned long priv) static void blk_mq_timeout_work(struct work_struct *work)
{ {
struct request_queue *q = (struct request_queue *)priv; struct request_queue *q =
container_of(work, struct request_queue, timeout_work);
struct blk_mq_timeout_data data = { struct blk_mq_timeout_data data = {
.next = 0, .next = 0,
.next_set = 0, .next_set = 0,
}; };
int i; int i;
if (blk_queue_enter(q, true))
return;
blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data); blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data);
if (data.next_set) { if (data.next_set) {
...@@ -638,6 +642,7 @@ static void blk_mq_rq_timer(unsigned long priv) ...@@ -638,6 +642,7 @@ static void blk_mq_rq_timer(unsigned long priv)
blk_mq_tag_idle(hctx); blk_mq_tag_idle(hctx);
} }
} }
blk_queue_exit(q);
} }
/* /*
...@@ -2015,7 +2020,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, ...@@ -2015,7 +2020,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
hctxs[i]->queue_num = i; hctxs[i]->queue_num = i;
} }
setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q); INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ); blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
q->nr_queues = nr_cpu_ids; q->nr_queues = nr_cpu_ids;
......
...@@ -127,13 +127,16 @@ static void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout ...@@ -127,13 +127,16 @@ static void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout
} }
} }
void blk_rq_timed_out_timer(unsigned long data) void blk_timeout_work(struct work_struct *work)
{ {
struct request_queue *q = (struct request_queue *) data; struct request_queue *q =
container_of(work, struct request_queue, timeout_work);
unsigned long flags, next = 0; unsigned long flags, next = 0;
struct request *rq, *tmp; struct request *rq, *tmp;
int next_set = 0; int next_set = 0;
if (blk_queue_enter(q, true))
return;
spin_lock_irqsave(q->queue_lock, flags); spin_lock_irqsave(q->queue_lock, flags);
list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list)
...@@ -143,6 +146,7 @@ void blk_rq_timed_out_timer(unsigned long data) ...@@ -143,6 +146,7 @@ void blk_rq_timed_out_timer(unsigned long data)
mod_timer(&q->timeout, round_jiffies_up(next)); mod_timer(&q->timeout, round_jiffies_up(next));
spin_unlock_irqrestore(q->queue_lock, flags); spin_unlock_irqrestore(q->queue_lock, flags);
blk_queue_exit(q);
} }
/** /**
......
...@@ -93,7 +93,7 @@ static inline void blk_flush_integrity(void) ...@@ -93,7 +93,7 @@ static inline void blk_flush_integrity(void)
} }
#endif #endif
void blk_rq_timed_out_timer(unsigned long data); void blk_timeout_work(struct work_struct *work);
unsigned long blk_rq_timeout(unsigned long timeout); unsigned long blk_rq_timeout(unsigned long timeout);
void blk_add_timer(struct request *req); void blk_add_timer(struct request *req);
void blk_delete_timer(struct request *); void blk_delete_timer(struct request *);
......
...@@ -407,6 +407,7 @@ struct request_queue { ...@@ -407,6 +407,7 @@ struct request_queue {
unsigned int rq_timeout; unsigned int rq_timeout;
struct timer_list timeout; struct timer_list timeout;
struct work_struct timeout_work;
struct list_head timeout_list; struct list_head timeout_list;
struct list_head icq_list; struct list_head icq_list;
......
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