/* * 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; WARN_ON(irqs_disabled()); rq->rq_disk = bd_disk; rq->end_io = done; spin_lock_irq(q->queue_lock); if (unlikely(blk_queue_dead(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 (rq->cmd_type == REQ_TYPE_PM_RESUME) q->request_fn(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);