]>
git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - block/blk-timeout.c
2 * Functions related to generic timeout handling of requests.
4 #include <linux/kernel.h>
5 #include <linux/module.h>
6 #include <linux/blkdev.h>
11 * blk_delete_timer - Delete/cancel timer for a given function.
12 * @req: request that we are canceling timer for
15 void blk_delete_timer(struct request
*req
)
17 struct request_queue
*q
= req
->q
;
22 if (!q
->rq_timed_out_fn
|| !req
->deadline
)
25 list_del_init(&req
->timeout_list
);
27 if (list_empty(&q
->timeout_list
))
28 del_timer(&q
->timeout
);
31 static void blk_rq_timed_out(struct request
*req
)
33 struct request_queue
*q
= req
->q
;
34 enum blk_eh_timer_return ret
;
36 ret
= q
->rq_timed_out_fn(req
);
39 __blk_complete_request(req
);
41 case BLK_EH_RESET_TIMER
:
42 blk_clear_rq_complete(req
);
45 case BLK_EH_NOT_HANDLED
:
47 * LLD handles this for now but in the future
48 * we can send a request msg to abort the command
49 * and we can move more of the generic scsi eh code to
54 printk(KERN_ERR
"block: bad eh return: %d\n", ret
);
59 void blk_rq_timed_out_timer(unsigned long data
)
61 struct request_queue
*q
= (struct request_queue
*) data
;
62 unsigned long flags
, uninitialized_var(next
), next_set
= 0;
63 struct request
*rq
, *tmp
;
65 spin_lock_irqsave(q
->queue_lock
, flags
);
67 list_for_each_entry_safe(rq
, tmp
, &q
->timeout_list
, timeout_list
) {
68 if (time_after_eq(jiffies
, rq
->deadline
)) {
69 list_del_init(&rq
->timeout_list
);
72 * Check if we raced with end io completion
74 if (blk_mark_rq_complete(rq
))
81 } else if (time_after(next
, rq
->deadline
))
85 if (next_set
&& !list_empty(&q
->timeout_list
))
86 mod_timer(&q
->timeout
, round_jiffies(next
));
88 spin_unlock_irqrestore(q
->queue_lock
, flags
);
92 * blk_abort_request -- Request request recovery for the specified command
93 * @req: pointer to the request of interest
95 * This function requests that the block layer start recovery for the
96 * request by deleting the timer and calling the q's timeout function.
97 * LLDDs who implement their own error recovery MAY ignore the timeout
98 * event if they generated blk_abort_req. Must hold queue lock.
100 void blk_abort_request(struct request
*req
)
102 blk_delete_timer(req
);
103 blk_rq_timed_out(req
);
105 EXPORT_SYMBOL_GPL(blk_abort_request
);
108 * blk_add_timer - Start timeout timer for a single request
109 * @req: request that is about to start running.
112 * Each request has its own timer, and as it is added to the queue, we
113 * set up the timer. When the request completes, we cancel the timer.
115 void blk_add_timer(struct request
*req
)
117 struct request_queue
*q
= req
->q
;
118 unsigned long expiry
;
120 if (!q
->rq_timed_out_fn
)
123 BUG_ON(!list_empty(&req
->timeout_list
));
124 BUG_ON(test_bit(REQ_ATOM_COMPLETE
, &req
->atomic_flags
));
127 req
->deadline
= jiffies
+ req
->timeout
;
129 req
->deadline
= jiffies
+ q
->rq_timeout
;
131 * Some LLDs, like scsi, peek at the timeout to prevent
132 * a command from being retried forever.
134 req
->timeout
= q
->rq_timeout
;
136 list_add_tail(&req
->timeout_list
, &q
->timeout_list
);
139 * If the timer isn't already pending or this timeout is earlier
140 * than an existing one, modify the timer. Round to next nearest
143 expiry
= round_jiffies(req
->deadline
);
146 * We use ->deadline == 0 to detect whether a timer was added or
147 * not, so just increase to next jiffy for that specific case
149 if (unlikely(!req
->deadline
))
152 if (!timer_pending(&q
->timeout
) ||
153 time_before(expiry
, q
->timeout
.expires
))
154 mod_timer(&q
->timeout
, expiry
);