diff options
Diffstat (limited to 'drivers/block/elevator.c')
| -rw-r--r-- | drivers/block/elevator.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c index 6b79b43..f831f08 100644 --- a/drivers/block/elevator.c +++ b/drivers/block/elevator.c @@ -220,11 +220,6 @@ void elevator_exit(elevator_t *e) kfree(e); } -static int elevator_global_init(void) -{ - return 0; -} - int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) { elevator_t *e = q->elevator; @@ -291,6 +286,13 @@ void elv_requeue_request(request_queue_t *q, struct request *rq) } /* + * the request is prepped and may have some resources allocated. + * allowing unprepped requests to pass this one may cause resource + * deadlock. turn on softbarrier. + */ + rq->flags |= REQ_SOFTBARRIER; + + /* * if iosched has an explicit requeue hook, then use that. otherwise * just put the request at the front of the queue */ @@ -322,7 +324,7 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where, int nrq = q->rq.count[READ] + q->rq.count[WRITE] - q->in_flight; - if (nrq == q->unplug_thresh) + if (nrq >= q->unplug_thresh) __generic_unplug_device(q); } } else @@ -386,6 +388,12 @@ struct request *elv_next_request(request_queue_t *q) if (ret == BLKPREP_OK) { break; } else if (ret == BLKPREP_DEFER) { + /* + * the request may have been (partially) prepped. + * we need to keep this request in the front to + * avoid resource deadlock. turn on softbarrier. + */ + rq->flags |= REQ_SOFTBARRIER; rq = NULL; break; } else if (ret == BLKPREP_KILL) { @@ -692,8 +700,6 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name) return len; } -module_init(elevator_global_init); - EXPORT_SYMBOL(elv_add_request); EXPORT_SYMBOL(__elv_add_request); EXPORT_SYMBOL(elv_requeue_request); |