111 lines
3.0 KiB
C
111 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Functions related to setting various queue properties from drivers
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/blk-mq.h>
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#include <linux/sched/sysctl.h>
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#include "blk.h"
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#include "blk-mq-sched.h"
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/**
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* blk_end_sync_rq - executes a completion event on a request
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* @rq: request to complete
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* @error: end I/O status of the request
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*/
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static void blk_end_sync_rq(struct request *rq, blk_status_t error)
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{
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struct completion *waiting = rq->end_io_data;
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rq->end_io_data = (void *)(uintptr_t)error;
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/*
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* complete last, if this is a stack request the process (and thus
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* the rq pointer) could be invalid right after this complete()
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*/
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complete(waiting);
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}
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/**
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* blk_execute_rq_nowait - insert a request to I/O scheduler for execution
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* @bd_disk: matching gendisk
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* @rq: request to insert
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* @at_head: insert request at head or tail of queue
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* @done: I/O completion handler
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*
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* Description:
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* Insert a fully prepared request at the back of the I/O scheduler queue
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* for execution. Don't wait for completion.
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*
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* Note:
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* This function will invoke @done directly if the queue is dead.
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*/
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void blk_execute_rq_nowait(struct gendisk *bd_disk, struct request *rq,
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int at_head, rq_end_io_fn *done)
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{
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WARN_ON(irqs_disabled());
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WARN_ON(!blk_rq_is_passthrough(rq));
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rq->rq_disk = bd_disk;
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rq->end_io = done;
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blk_account_io_start(rq);
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/*
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* don't check dying flag for MQ because the request won't
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* be reused after dying flag is set
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*/
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blk_mq_sched_insert_request(rq, at_head, true, false);
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}
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EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
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static bool blk_rq_is_poll(struct request *rq)
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{
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return rq->mq_hctx && rq->mq_hctx->type == HCTX_TYPE_POLL;
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}
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static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
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{
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do {
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blk_poll(rq->q, request_to_qc_t(rq->mq_hctx, rq), true);
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cond_resched();
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} while (!completion_done(wait));
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}
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/**
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* blk_execute_rq - insert a request into queue for execution
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* @bd_disk: matching gendisk
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* @rq: request to insert
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* @at_head: insert request at head or tail of queue
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*
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* Description:
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* Insert a fully prepared request at the back of the I/O scheduler queue
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* for execution and wait for completion.
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* Return: The blk_status_t result provided to blk_mq_end_request().
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*/
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blk_status_t blk_execute_rq(struct gendisk *bd_disk, struct request *rq, int at_head)
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{
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DECLARE_COMPLETION_ONSTACK(wait);
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unsigned long hang_check;
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rq->end_io_data = &wait;
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blk_execute_rq_nowait(bd_disk, rq, at_head, blk_end_sync_rq);
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/* Prevent hang_check timer from firing at us during very long I/O */
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hang_check = sysctl_hung_task_timeout_secs;
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if (blk_rq_is_poll(rq))
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blk_rq_poll_completion(rq, &wait);
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else if (hang_check)
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while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2)));
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else
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wait_for_completion_io(&wait);
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return (blk_status_t)(uintptr_t)rq->end_io_data;
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}
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EXPORT_SYMBOL(blk_execute_rq);
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