FreeBSD/Linux Kernel Cross Reference
sys/block/blk-exec.c

     /*
      * Functions related to setting various queue properties from drivers
      */
     #include <linux/kernel.h>
     #include <linux/module.h>
     #include <linux/bio.h>
     #include <linux/blkdev.h>
     
     #include "blk.h"
    
    /*
     * for max sense size
     */
    #include <scsi/scsi_cmnd.h>
    
    /**
     * blk_end_sync_rq - executes a completion event on a request
     * @rq: request to complete
     * @error: end I/O status of the request
     */
    static void blk_end_sync_rq(struct request *rq, int error)
    {
            struct completion *waiting = rq->end_io_data;
    
            rq->end_io_data = NULL;
            __blk_put_request(rq->q, rq);
    
            /*
             * complete last, if this is a stack request the process (and thus
             * the rq pointer) could be invalid right after this complete()
             */
            complete(waiting);
    }
    
    /**
     * blk_execute_rq_nowait - insert a request into queue for execution
     * @q:          queue to insert the request in
     * @bd_disk:    matching gendisk
     * @rq:         request to insert
     * @at_head:    insert request at head or tail of queue
     * @done:       I/O completion handler
     *
     * Description:
     *    Insert a fully prepared request at the back of the I/O scheduler queue
     *    for execution.  Don't wait for completion.
     *
     * Note:
     *    This function will invoke @done directly if the queue is dead.
     */
    void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
                               struct request *rq, int at_head,
                               rq_end_io_fn *done)
    {
            int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
            bool is_pm_resume;
    
            WARN_ON(irqs_disabled());
    
            rq->rq_disk = bd_disk;
            rq->end_io = done;
            /*
             * need to check this before __blk_run_queue(), because rq can
             * be freed before that returns.
             */
            is_pm_resume = rq->cmd_type == REQ_TYPE_PM_RESUME;
    
            spin_lock_irq(q->queue_lock);
    
            if (unlikely(blk_queue_dying(q))) {
                    rq->errors = -ENXIO;
                    if (rq->end_io)
                            rq->end_io(rq, rq->errors);
                    spin_unlock_irq(q->queue_lock);
                    return;
            }
    
            __elv_add_request(q, rq, where);
            __blk_run_queue(q);
            /* the queue is stopped so it won't be run */
            if (is_pm_resume)
                    __blk_run_queue_uncond(q);
            spin_unlock_irq(q->queue_lock);
    }
    EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
    
    /**
     * blk_execute_rq - insert a request into queue for execution
     * @q:          queue to insert the request in
     * @bd_disk:    matching gendisk
     * @rq:         request to insert
     * @at_head:    insert request at head or tail of queue
     *
     * Description:
     *    Insert a fully prepared request at the back of the I/O scheduler queue
     *    for execution and wait for completion.
     */
    int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
                       struct request *rq, int at_head)
    {
           DECLARE_COMPLETION_ONSTACK(wait);
           char sense[SCSI_SENSE_BUFFERSIZE];
           int err = 0;
           unsigned long hang_check;
   
           /*
            * we need an extra reference to the request, so we can look at
            * it after io completion
            */
           rq->ref_count++;
   
           if (!rq->sense) {
                   memset(sense, 0, sizeof(sense));
                   rq->sense = sense;
                   rq->sense_len = 0;
           }
   
           rq->end_io_data = &wait;
           blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
   
           /* Prevent hang_check timer from firing at us during very long I/O */
           hang_check = sysctl_hung_task_timeout_secs;
           if (hang_check)
                   while (!wait_for_completion_timeout(&wait, hang_check * (HZ/2)));
           else
                   wait_for_completion(&wait);
   
           if (rq->errors)
                   err = -EIO;
   
           return err;
   }
   EXPORT_SYMBOL(blk_execute_rq);

Cache object: f16ed0257a9a5904dc9aeef2ae19d5e2