Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Functions related to generic timeout handling of requests. |
| 3 | */ |
| 4 | #include <linux/kernel.h> |
| 5 | #include <linux/module.h> |
| 6 | #include <linux/blkdev.h> |
Jens Axboe | 581d4e2 | 2008-09-14 05:56:33 -0700 | [diff] [blame] | 7 | #include <linux/fault-inject.h> |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 8 | |
| 9 | #include "blk.h" |
| 10 | |
Jens Axboe | 581d4e2 | 2008-09-14 05:56:33 -0700 | [diff] [blame] | 11 | #ifdef CONFIG_FAIL_IO_TIMEOUT |
| 12 | |
| 13 | static DECLARE_FAULT_ATTR(fail_io_timeout); |
| 14 | |
| 15 | static int __init setup_fail_io_timeout(char *str) |
| 16 | { |
| 17 | return setup_fault_attr(&fail_io_timeout, str); |
| 18 | } |
| 19 | __setup("fail_io_timeout=", setup_fail_io_timeout); |
| 20 | |
| 21 | int blk_should_fake_timeout(struct request_queue *q) |
| 22 | { |
| 23 | if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags)) |
| 24 | return 0; |
| 25 | |
| 26 | return should_fail(&fail_io_timeout, 1); |
| 27 | } |
| 28 | |
| 29 | static int __init fail_io_timeout_debugfs(void) |
| 30 | { |
| 31 | return init_fault_attr_dentries(&fail_io_timeout, "fail_io_timeout"); |
| 32 | } |
| 33 | |
| 34 | late_initcall(fail_io_timeout_debugfs); |
| 35 | |
| 36 | ssize_t part_timeout_show(struct device *dev, struct device_attribute *attr, |
| 37 | char *buf) |
| 38 | { |
| 39 | struct gendisk *disk = dev_to_disk(dev); |
| 40 | int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags); |
| 41 | |
| 42 | return sprintf(buf, "%d\n", set != 0); |
| 43 | } |
| 44 | |
| 45 | ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr, |
| 46 | const char *buf, size_t count) |
| 47 | { |
| 48 | struct gendisk *disk = dev_to_disk(dev); |
| 49 | int val; |
| 50 | |
| 51 | if (count) { |
| 52 | struct request_queue *q = disk->queue; |
| 53 | char *p = (char *) buf; |
| 54 | |
| 55 | val = simple_strtoul(p, &p, 10); |
| 56 | spin_lock_irq(q->queue_lock); |
| 57 | if (val) |
| 58 | queue_flag_set(QUEUE_FLAG_FAIL_IO, q); |
| 59 | else |
| 60 | queue_flag_clear(QUEUE_FLAG_FAIL_IO, q); |
| 61 | spin_unlock_irq(q->queue_lock); |
| 62 | } |
| 63 | |
| 64 | return count; |
| 65 | } |
| 66 | |
| 67 | #endif /* CONFIG_FAIL_IO_TIMEOUT */ |
| 68 | |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 69 | /* |
| 70 | * blk_delete_timer - Delete/cancel timer for a given function. |
| 71 | * @req: request that we are canceling timer for |
| 72 | * |
| 73 | */ |
| 74 | void blk_delete_timer(struct request *req) |
| 75 | { |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 76 | list_del_init(&req->timeout_list); |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 77 | } |
| 78 | |
| 79 | static void blk_rq_timed_out(struct request *req) |
| 80 | { |
| 81 | struct request_queue *q = req->q; |
| 82 | enum blk_eh_timer_return ret; |
| 83 | |
| 84 | ret = q->rq_timed_out_fn(req); |
| 85 | switch (ret) { |
| 86 | case BLK_EH_HANDLED: |
| 87 | __blk_complete_request(req); |
| 88 | break; |
| 89 | case BLK_EH_RESET_TIMER: |
| 90 | blk_clear_rq_complete(req); |
| 91 | blk_add_timer(req); |
| 92 | break; |
| 93 | case BLK_EH_NOT_HANDLED: |
| 94 | /* |
| 95 | * LLD handles this for now but in the future |
| 96 | * we can send a request msg to abort the command |
| 97 | * and we can move more of the generic scsi eh code to |
| 98 | * the blk layer. |
| 99 | */ |
| 100 | break; |
| 101 | default: |
| 102 | printk(KERN_ERR "block: bad eh return: %d\n", ret); |
| 103 | break; |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | void blk_rq_timed_out_timer(unsigned long data) |
| 108 | { |
| 109 | struct request_queue *q = (struct request_queue *) data; |
malahal@us.ibm.com | 565e411 | 2008-10-30 08:51:58 +0100 | [diff] [blame] | 110 | unsigned long flags, next = 0; |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 111 | struct request *rq, *tmp; |
| 112 | |
| 113 | spin_lock_irqsave(q->queue_lock, flags); |
| 114 | |
| 115 | list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) { |
| 116 | if (time_after_eq(jiffies, rq->deadline)) { |
| 117 | list_del_init(&rq->timeout_list); |
| 118 | |
| 119 | /* |
| 120 | * Check if we raced with end io completion |
| 121 | */ |
| 122 | if (blk_mark_rq_complete(rq)) |
| 123 | continue; |
| 124 | blk_rq_timed_out(rq); |
malahal@us.ibm.com | 565e411 | 2008-10-30 08:51:58 +0100 | [diff] [blame] | 125 | } else { |
| 126 | if (!next || time_after(next, rq->deadline)) |
| 127 | next = rq->deadline; |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 128 | } |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 129 | } |
| 130 | |
Jens Axboe | 65d3618 | 2008-10-30 08:53:02 +0100 | [diff] [blame] | 131 | /* |
| 132 | * next can never be 0 here with the list non-empty, since we always |
| 133 | * bump ->deadline to 1 so we can detect if the timer was ever added |
| 134 | * or not. See comment in blk_add_timer() |
| 135 | */ |
| 136 | if (next) |
Alan Stern | 7838c15 | 2008-11-06 08:42:49 +0100 | [diff] [blame] | 137 | mod_timer(&q->timeout, round_jiffies_up(next)); |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 138 | |
| 139 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 140 | } |
| 141 | |
| 142 | /** |
| 143 | * blk_abort_request -- Request request recovery for the specified command |
| 144 | * @req: pointer to the request of interest |
| 145 | * |
| 146 | * This function requests that the block layer start recovery for the |
| 147 | * request by deleting the timer and calling the q's timeout function. |
| 148 | * LLDDs who implement their own error recovery MAY ignore the timeout |
| 149 | * event if they generated blk_abort_req. Must hold queue lock. |
| 150 | */ |
| 151 | void blk_abort_request(struct request *req) |
| 152 | { |
Jens Axboe | 7ba1fba | 2008-09-16 09:54:11 -0700 | [diff] [blame] | 153 | if (blk_mark_rq_complete(req)) |
| 154 | return; |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 155 | blk_delete_timer(req); |
| 156 | blk_rq_timed_out(req); |
| 157 | } |
| 158 | EXPORT_SYMBOL_GPL(blk_abort_request); |
| 159 | |
| 160 | /** |
| 161 | * blk_add_timer - Start timeout timer for a single request |
| 162 | * @req: request that is about to start running. |
| 163 | * |
| 164 | * Notes: |
| 165 | * Each request has its own timer, and as it is added to the queue, we |
| 166 | * set up the timer. When the request completes, we cancel the timer. |
| 167 | */ |
| 168 | void blk_add_timer(struct request *req) |
| 169 | { |
| 170 | struct request_queue *q = req->q; |
| 171 | unsigned long expiry; |
| 172 | |
| 173 | if (!q->rq_timed_out_fn) |
| 174 | return; |
| 175 | |
| 176 | BUG_ON(!list_empty(&req->timeout_list)); |
| 177 | BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags)); |
| 178 | |
| 179 | if (req->timeout) |
| 180 | req->deadline = jiffies + req->timeout; |
| 181 | else { |
| 182 | req->deadline = jiffies + q->rq_timeout; |
| 183 | /* |
| 184 | * Some LLDs, like scsi, peek at the timeout to prevent |
| 185 | * a command from being retried forever. |
| 186 | */ |
| 187 | req->timeout = q->rq_timeout; |
| 188 | } |
| 189 | list_add_tail(&req->timeout_list, &q->timeout_list); |
| 190 | |
| 191 | /* |
| 192 | * If the timer isn't already pending or this timeout is earlier |
Alan Stern | 7838c15 | 2008-11-06 08:42:49 +0100 | [diff] [blame] | 193 | * than an existing one, modify the timer. Round up to next nearest |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 194 | * second. |
| 195 | */ |
Alan Stern | 7838c15 | 2008-11-06 08:42:49 +0100 | [diff] [blame] | 196 | expiry = round_jiffies_up(req->deadline); |
Jens Axboe | 242f9dc | 2008-09-14 05:55:09 -0700 | [diff] [blame] | 197 | |
| 198 | if (!timer_pending(&q->timeout) || |
| 199 | time_before(expiry, q->timeout.expires)) |
| 200 | mod_timer(&q->timeout, expiry); |
| 201 | } |
Mike Anderson | 11914a5 | 2008-09-13 20:31:27 +0200 | [diff] [blame] | 202 | |
| 203 | /** |
| 204 | * blk_abort_queue -- Abort all request on given queue |
| 205 | * @queue: pointer to queue |
| 206 | * |
| 207 | */ |
| 208 | void blk_abort_queue(struct request_queue *q) |
| 209 | { |
| 210 | unsigned long flags; |
| 211 | struct request *rq, *tmp; |
Hannes Reinecke | be987fd | 2009-02-18 10:30:15 +0100 | [diff] [blame] | 212 | LIST_HEAD(list); |
Mike Anderson | 11914a5 | 2008-09-13 20:31:27 +0200 | [diff] [blame] | 213 | |
Jens Axboe | b759113 | 2009-04-17 08:36:50 +0200 | [diff] [blame] | 214 | /* |
| 215 | * Not a request based block device, nothing to abort |
| 216 | */ |
| 217 | if (!q->request_fn) |
| 218 | return; |
| 219 | |
Mike Anderson | 11914a5 | 2008-09-13 20:31:27 +0200 | [diff] [blame] | 220 | spin_lock_irqsave(q->queue_lock, flags); |
| 221 | |
| 222 | elv_abort_queue(q); |
| 223 | |
Hannes Reinecke | be987fd | 2009-02-18 10:30:15 +0100 | [diff] [blame] | 224 | /* |
| 225 | * Splice entries to local list, to avoid deadlocking if entries |
| 226 | * get readded to the timeout list by error handling |
| 227 | */ |
| 228 | list_splice_init(&q->timeout_list, &list); |
| 229 | |
| 230 | list_for_each_entry_safe(rq, tmp, &list, timeout_list) |
Mike Anderson | 11914a5 | 2008-09-13 20:31:27 +0200 | [diff] [blame] | 231 | blk_abort_request(rq); |
| 232 | |
Hannes Reinecke | 17d5c8c | 2009-04-23 10:32:59 +0200 | [diff] [blame^] | 233 | /* |
| 234 | * Occasionally, blk_abort_request() will return without |
| 235 | * deleting the element from the list. Make sure we add those back |
| 236 | * instead of leaving them on the local stack list. |
| 237 | */ |
| 238 | list_splice(&list, &q->timeout_list); |
| 239 | |
Mike Anderson | 11914a5 | 2008-09-13 20:31:27 +0200 | [diff] [blame] | 240 | spin_unlock_irqrestore(q->queue_lock, flags); |
| 241 | |
| 242 | } |
| 243 | EXPORT_SYMBOL_GPL(blk_abort_queue); |