Git Repo - linux.git/blame_incremental

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Commit	Line	Data
	1	/*
	2	* Functions related to setting various queue properties from drivers
	3	*/
	4	#include <linux/kernel.h>
	5	#include <linux/module.h>
	6	#include <linux/bio.h>
	7	#include <linux/blkdev.h>
	8	#include <linux/blk-mq.h>
	9	#include <linux/sched/sysctl.h>
	10
	11	#include "blk.h"
	12
	13	/*
	14	* for max sense size
	15	*/
	16	#include <scsi/scsi_cmnd.h>
	17
	18	/**
	19	* blk_end_sync_rq - executes a completion event on a request
	20	* @rq: request to complete
	21	* @error: end I/O status of the request
	22	*/
	23	static void blk_end_sync_rq(struct request *rq, int error)
	24	{
	25	struct completion *waiting = rq->end_io_data;
	26
	27	rq->end_io_data = NULL;
	28
	29	/*
	30	* complete last, if this is a stack request the process (and thus
	31	* the rq pointer) could be invalid right after this complete()
	32	*/
	33	complete(waiting);
	34	}
	35
	36	/**
	37	* blk_execute_rq_nowait - insert a request into queue for execution
	38	* @q: queue to insert the request in
	39	* @bd_disk: matching gendisk
	40	* @rq: request to insert
	41	* @at_head: insert request at head or tail of queue
	42	* @done: I/O completion handler
	43	*
	44	* Description:
	45	* Insert a fully prepared request at the back of the I/O scheduler queue
	46	* for execution. Don't wait for completion.
	47	*
	48	* Note:
	49	* This function will invoke @done directly if the queue is dead.
	50	*/
	51	void blk_execute_rq_nowait(struct request_queue q, struct gendisk bd_disk,
	52	struct request *rq, int at_head,
	53	rq_end_io_fn *done)
	54	{
	55	int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
	56	bool is_pm_resume;
	57
	58	WARN_ON(irqs_disabled());
	59
	60	rq->rq_disk = bd_disk;
	61	rq->end_io = done;
	62
	63	if (q->mq_ops) {
	64	blk_mq_insert_request(q, rq, true);
	65	return;
	66	}
	67
	68	/*
	69	* need to check this before __blk_run_queue(), because rq can
	70	* be freed before that returns.
	71	*/
	72	is_pm_resume = rq->cmd_type == REQ_TYPE_PM_RESUME;
	73
	74	spin_lock_irq(q->queue_lock);
	75
	76	if (unlikely(blk_queue_dying(q))) {
	77	rq->cmd_flags \|= REQ_QUIET;
	78	rq->errors = -ENXIO;
	79	__blk_end_request_all(rq, rq->errors);
	80	spin_unlock_irq(q->queue_lock);
	81	return;
	82	}
	83
	84	__elv_add_request(q, rq, where);
	85	__blk_run_queue(q);
	86	/* the queue is stopped so it won't be run */
	87	if (is_pm_resume)
	88	__blk_run_queue_uncond(q);
	89	spin_unlock_irq(q->queue_lock);
	90	}
	91	EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
	92
	93	/**
	94	* blk_execute_rq - insert a request into queue for execution
	95	* @q: queue to insert the request in
	96	* @bd_disk: matching gendisk
	97	* @rq: request to insert
	98	* @at_head: insert request at head or tail of queue
	99	*
	100	* Description:
	101	* Insert a fully prepared request at the back of the I/O scheduler queue
	102	* for execution and wait for completion.
	103	*/
	104	int blk_execute_rq(struct request_queue q, struct gendisk bd_disk,
	105	struct request *rq, int at_head)
	106	{
	107	DECLARE_COMPLETION_ONSTACK(wait);
	108	char sense[SCSI_SENSE_BUFFERSIZE];
	109	int err = 0;
	110	unsigned long hang_check;
	111
	112	if (!rq->sense) {
	113	memset(sense, 0, sizeof(sense));
	114	rq->sense = sense;
	115	rq->sense_len = 0;
	116	}
	117
	118	rq->end_io_data = &wait;
	119	blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
	120
	121	/* Prevent hang_check timer from firing at us during very long I/O */
	122	hang_check = sysctl_hung_task_timeout_secs;
	123	if (hang_check)
	124	while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
	125	else
	126	wait_for_completion_io(&wait);
	127
	128	if (rq->errors)
	129	err = -EIO;
	130
	131	return err;
	132	}
	133	EXPORT_SYMBOL(blk_execute_rq);