block: unify request timeout handling (242f9dcb) · Commits · 戴 / test

block/Makefile

+2 −2

Original line number	Diff line number	Diff line
		@@ -4,8 +4,8 @@

		obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \
		blk-barrier.o blk-settings.o blk-ioc.o blk-map.o \
		blk-exec.o blk-merge.o blk-softirq.o ioctl.o genhd.o \
		scsi_ioctl.o cmd-filter.o
		blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \
		ioctl.o genhd.o scsi_ioctl.o cmd-filter.o

		obj-$(CONFIG_BLK_DEV_BSG) += bsg.o
		obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o

block/blk-core.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -110,6 +110,7 @@ void blk_rq_init(struct request_queue q, struct request rq)
		memset(rq, 0, sizeof(*rq));

		INIT_LIST_HEAD(&rq->queuelist);
		INIT_LIST_HEAD(&rq->timeout_list);
		rq->cpu = -1;
		rq->q = q;
		rq->sector = rq->hard_sector = (sector_t) -1;
		@@ -490,6 +491,8 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
		}

		init_timer(&q->unplug_timer);
		setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
		INIT_LIST_HEAD(&q->timeout_list);

		kobject_init(&q->kobj, &blk_queue_ktype);

		@@ -897,6 +900,8 @@ EXPORT_SYMBOL(blk_start_queueing);
		*/
		void blk_requeue_request(struct request_queue q, struct request rq)
		{
		blk_delete_timer(rq);
		blk_clear_rq_complete(rq);
		blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);

		if (blk_rq_tagged(rq))
		@@ -1650,6 +1655,8 @@ static void end_that_request_last(struct request *req, int error)
		{
		struct gendisk *disk = req->rq_disk;

		blk_delete_timer(req);

		if (blk_rq_tagged(req))
		blk_queue_end_tag(req->q, req);

block/blk-settings.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -77,6 +77,18 @@ void blk_queue_softirq_done(struct request_queue q, softirq_done_fn fn)
		}
		EXPORT_SYMBOL(blk_queue_softirq_done);

		void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
		{
		q->rq_timeout = timeout;
		}
		EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);

		void blk_queue_rq_timed_out(struct request_queue q, rq_timed_out_fn fn)
		{
		q->rq_timed_out_fn = fn;
		}
		EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out);

		/**
		* blk_queue_make_request - define an alternate make_request function for a device
		* @q: the request queue for the device to be affected

block/blk-softirq.c

+18 −12

Original line number	Diff line number	Diff line
		@@ -101,18 +101,7 @@ static struct notifier_block __cpuinitdata blk_cpu_notifier = {
		.notifier_call = blk_cpu_notify,
		};

		/**
		* blk_complete_request - end I/O on a request
		* @req: the request being processed
		*
		* Description:
		* Ends all I/O on a request. It does not handle partial completions,
		* unless the driver actually implements this in its completion callback
		* through requeueing. The actual completion happens out-of-order,
		* through a softirq handler. The user must have registered a completion
		* callback through blk_queue_softirq_done().
		**/
		void blk_complete_request(struct request *req)
		void __blk_complete_request(struct request *req)
		{
		struct request_queue *q = req->q;
		unsigned long flags;
		@@ -151,6 +140,23 @@ do_local:

		local_irq_restore(flags);
		}

		/**
		* blk_complete_request - end I/O on a request
		* @req: the request being processed
		*
		* Description:
		* Ends all I/O on a request. It does not handle partial completions,
		* unless the driver actually implements this in its completion callback
		* through requeueing. The actual completion happens out-of-order,
		* through a softirq handler. The user must have registered a completion
		* callback through blk_queue_softirq_done().
		**/
		void blk_complete_request(struct request *req)
		{
		if (!blk_mark_rq_complete(req))
		__blk_complete_request(req);
		}
		EXPORT_SYMBOL(blk_complete_request);

		__init int blk_softirq_init(void)

block/blk-timeout.c

0 → 100644

+155 −0

Original line number	Diff line number	Diff line
		/*
		* Functions related to generic timeout handling of requests.
		*/
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/blkdev.h>

		#include "blk.h"

		/*
		* 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)
		{
		struct request_queue *q = req->q;

		/*
		* Nothing to detach
		*/
		if (!q->rq_timed_out_fn \|\| !req->deadline)
		return;

		list_del_init(&req->timeout_list);

		if (list_empty(&q->timeout_list))
		del_timer(&q->timeout);
		}

		static void blk_rq_timed_out(struct request *req)
		{
		struct request_queue *q = req->q;
		enum blk_eh_timer_return ret;

		ret = q->rq_timed_out_fn(req);
		switch (ret) {
		case BLK_EH_HANDLED:
		__blk_complete_request(req);
		break;
		case BLK_EH_RESET_TIMER:
		blk_clear_rq_complete(req);
		blk_add_timer(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;
		}
		}

		void blk_rq_timed_out_timer(unsigned long data)
		{
		struct request_queue q = (struct request_queue ) data;
		unsigned long flags, uninitialized_var(next), next_set = 0;
		struct request rq, tmp;

		spin_lock_irqsave(q->queue_lock, flags);

		list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) {
		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))
		continue;
		blk_rq_timed_out(rq);
		}
		if (!next_set) {
		next = rq->deadline;
		next_set = 1;
		} else if (time_after(next, rq->deadline))
		next = rq->deadline;
		}

		if (next_set && !list_empty(&q->timeout_list))
		mod_timer(&q->timeout, round_jiffies(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)
		{
		blk_delete_timer(req);
		blk_rq_timed_out(req);
		}
		EXPORT_SYMBOL_GPL(blk_abort_request);

		/**
		* 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 (!q->rq_timed_out_fn)
		return;

		BUG_ON(!list_empty(&req->timeout_list));
		BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));

		if (req->timeout)
		req->deadline = jiffies + req->timeout;
		else {
		req->deadline = jiffies + q->rq_timeout;
		/*
		* Some LLDs, like scsi, peek at the timeout to prevent
		* a command from being retried forever.
		*/
		req->timeout = q->rq_timeout;
		}
		list_add_tail(&req->timeout_list, &q->timeout_list);

		/*
		* If the timer isn't already pending or this timeout is earlier
		* than an existing one, modify the timer. Round to next nearest
		* second.
		*/
		expiry = round_jiffies(req->deadline);

		/*
		* We use ->deadline == 0 to detect whether a timer was added or
		* not, so just increase to next jiffy for that specific case
		*/
		if (unlikely(!req->deadline))
		req->deadline = 1;

		if (!timer_pending(&q->timeout) \|\|
		time_before(expiry, q->timeout.expires))
		mod_timer(&q->timeout, expiry);
		}

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