From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/block/blk-timeout.c | 235 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 235 insertions(+) create mode 100644 kernel/block/blk-timeout.c (limited to 'kernel/block/blk-timeout.c') diff --git a/kernel/block/blk-timeout.c b/kernel/block/blk-timeout.c new file mode 100644 index 000000000..246dfb16c --- /dev/null +++ b/kernel/block/blk-timeout.c @@ -0,0 +1,235 @@ +/* + * Functions related to generic timeout handling of requests. + */ +#include +#include +#include +#include + +#include "blk.h" +#include "blk-mq.h" + +#ifdef CONFIG_FAIL_IO_TIMEOUT + +static DECLARE_FAULT_ATTR(fail_io_timeout); + +static int __init setup_fail_io_timeout(char *str) +{ + return setup_fault_attr(&fail_io_timeout, str); +} +__setup("fail_io_timeout=", setup_fail_io_timeout); + +int blk_should_fake_timeout(struct request_queue *q) +{ + if (!test_bit(QUEUE_FLAG_FAIL_IO, &q->queue_flags)) + return 0; + + return should_fail(&fail_io_timeout, 1); +} + +static int __init fail_io_timeout_debugfs(void) +{ + struct dentry *dir = fault_create_debugfs_attr("fail_io_timeout", + NULL, &fail_io_timeout); + + return PTR_ERR_OR_ZERO(dir); +} + +late_initcall(fail_io_timeout_debugfs); + +ssize_t part_timeout_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + int set = test_bit(QUEUE_FLAG_FAIL_IO, &disk->queue->queue_flags); + + return sprintf(buf, "%d\n", set != 0); +} + +ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct gendisk *disk = dev_to_disk(dev); + int val; + + if (count) { + struct request_queue *q = disk->queue; + char *p = (char *) buf; + + val = simple_strtoul(p, &p, 10); + spin_lock_irq(q->queue_lock); + if (val) + queue_flag_set(QUEUE_FLAG_FAIL_IO, q); + else + queue_flag_clear(QUEUE_FLAG_FAIL_IO, q); + spin_unlock_irq(q->queue_lock); + } + + return count; +} + +#endif /* CONFIG_FAIL_IO_TIMEOUT */ + +/* + * blk_delete_timer - Delete/cancel timer for a given function. + * @req: request that we are canceling timer for + * + */ +void blk_delete_timer(struct request *req) +{ + list_del_init(&req->timeout_list); +} + +static void blk_rq_timed_out(struct request *req) +{ + struct request_queue *q = req->q; + enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER; + + if (q->rq_timed_out_fn) + ret = q->rq_timed_out_fn(req); + switch (ret) { + case BLK_EH_HANDLED: + /* Can we use req->errors here? */ + __blk_complete_request(req); + break; + case BLK_EH_RESET_TIMER: + blk_add_timer(req); + blk_clear_rq_complete(req); + break; + case BLK_EH_NOT_HANDLED: + /* + * LLD handles this for now but in the future + * we can send a request msg to abort the command + * and we can move more of the generic scsi eh code to + * the blk layer. + */ + break; + default: + printk(KERN_ERR "block: bad eh return: %d\n", ret); + break; + } +} + +static void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout, + unsigned int *next_set) +{ + if (time_after_eq(jiffies, rq->deadline)) { + list_del_init(&rq->timeout_list); + + /* + * Check if we raced with end io completion + */ + if (!blk_mark_rq_complete(rq)) + blk_rq_timed_out(rq); + } else if (!*next_set || time_after(*next_timeout, rq->deadline)) { + *next_timeout = rq->deadline; + *next_set = 1; + } +} + +void blk_rq_timed_out_timer(unsigned long data) +{ + struct request_queue *q = (struct request_queue *) data; + unsigned long flags, next = 0; + struct request *rq, *tmp; + int next_set = 0; + + spin_lock_irqsave(q->queue_lock, flags); + + list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) + blk_rq_check_expired(rq, &next, &next_set); + + if (next_set) + mod_timer(&q->timeout, round_jiffies_up(next)); + + spin_unlock_irqrestore(q->queue_lock, flags); +} + +/** + * blk_abort_request -- Request request recovery for the specified command + * @req: pointer to the request of interest + * + * This function requests that the block layer start recovery for the + * request by deleting the timer and calling the q's timeout function. + * LLDDs who implement their own error recovery MAY ignore the timeout + * event if they generated blk_abort_req. Must hold queue lock. + */ +void blk_abort_request(struct request *req) +{ + if (blk_mark_rq_complete(req)) + return; + blk_delete_timer(req); + if (req->q->mq_ops) + blk_mq_rq_timed_out(req, false); + else + blk_rq_timed_out(req); +} +EXPORT_SYMBOL_GPL(blk_abort_request); + +unsigned long blk_rq_timeout(unsigned long timeout) +{ + unsigned long maxt; + + maxt = round_jiffies_up(jiffies + BLK_MAX_TIMEOUT); + if (time_after(timeout, maxt)) + timeout = maxt; + + return timeout; +} + +/** + * blk_add_timer - Start timeout timer for a single request + * @req: request that is about to start running. + * + * Notes: + * Each request has its own timer, and as it is added to the queue, we + * set up the timer. When the request completes, we cancel the timer. + */ +void blk_add_timer(struct request *req) +{ + struct request_queue *q = req->q; + unsigned long expiry; + + if (req->cmd_flags & REQ_NO_TIMEOUT) + return; + + /* blk-mq has its own handler, so we don't need ->rq_timed_out_fn */ + if (!q->mq_ops && !q->rq_timed_out_fn) + return; + + BUG_ON(!list_empty(&req->timeout_list)); + + /* + * Some LLDs, like scsi, peek at the timeout to prevent a + * command from being retried forever. + */ + if (!req->timeout) + req->timeout = q->rq_timeout; + + req->deadline = jiffies + req->timeout; + if (!q->mq_ops) + list_add_tail(&req->timeout_list, &req->q->timeout_list); + + /* + * If the timer isn't already pending or this timeout is earlier + * than an existing one, modify the timer. Round up to next nearest + * second. + */ + expiry = blk_rq_timeout(round_jiffies_up(req->deadline)); + + if (!timer_pending(&q->timeout) || + time_before(expiry, q->timeout.expires)) { + unsigned long diff = q->timeout.expires - expiry; + + /* + * Due to added timer slack to group timers, the timer + * will often be a little in front of what we asked for. + * So apply some tolerance here too, otherwise we keep + * modifying the timer because expires for value X + * will be X + something. + */ + if (!timer_pending(&q->timeout) || (diff >= HZ / 2)) + mod_timer(&q->timeout, expiry); + } + +} -- cgit 1.2.3-korg