X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=block%2Fblk-timeout.c;h=1ba7e0aca8781b55ce14fa54491da8f81505b747;hp=9b4ad138bb33a4559a98fec2e0edc2136b8eff52;hb=e071041be037eca208b62b84469a06bdfc692bea;hpb=581d4e28d9195aa8b2231383dbabc288988d615e

diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 9b4ad13..1ba7e0a 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -73,18 +73,7 @@ ssize_t part_timeout_store(struct device *dev, struct device_attribute *attr,
  */
 void blk_delete_timer(struct request *req)
 {
-	struct request_queue *q = req->q;
-
-	/*
-	 * Nothing to detach
-	 */
-	if (!q->rq_timed_out_fn || !req->deadline)
-		return;
-
 	list_del_init(&req->timeout_list);
-
-	if (list_empty(&q->timeout_list))
-		del_timer(&q->timeout);
 }
 
 static void blk_rq_timed_out(struct request *req)
@@ -118,7 +107,7 @@ static void blk_rq_timed_out(struct request *req)
 void blk_rq_timed_out_timer(unsigned long data)
 {
 	struct request_queue *q = (struct request_queue *) data;
-	unsigned long flags, uninitialized_var(next), next_set = 0;
+	unsigned long flags, next = 0;
 	struct request *rq, *tmp;
 
 	spin_lock_irqsave(q->queue_lock, flags);
@@ -133,16 +122,17 @@ void blk_rq_timed_out_timer(unsigned long data)
 			if (blk_mark_rq_complete(rq))
 				continue;
 			blk_rq_timed_out(rq);
-		}
-		if (!next_set) {
-			next = rq->deadline;
-			next_set = 1;
-		} else if (time_after(next, rq->deadline))
+		} else if (!next || time_after(next, rq->deadline))
 			next = rq->deadline;
 	}
 
-	if (next_set && !list_empty(&q->timeout_list))
-		mod_timer(&q->timeout, round_jiffies(next));
+	/*
+	 * next can never be 0 here with the list non-empty, since we always
+	 * bump ->deadline to 1 so we can detect if the timer was ever added
+	 * or not. See comment in blk_add_timer()
+	 */
+	if (next)
+		mod_timer(&q->timeout, round_jiffies_up(next));
 
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }
@@ -158,6 +148,8 @@ void blk_rq_timed_out_timer(unsigned long data)
  */
 void blk_abort_request(struct request *req)
 {
+	if (blk_mark_rq_complete(req))
+		return;
 	blk_delete_timer(req);
 	blk_rq_timed_out(req);
 }
@@ -182,31 +174,22 @@ void blk_add_timer(struct request *req)
 	BUG_ON(!list_empty(&req->timeout_list));
 	BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
 
-	if (req->timeout)
-		req->deadline = jiffies + req->timeout;
-	else {
-		req->deadline = jiffies + q->rq_timeout;
-		/*
-		 * Some LLDs, like scsi, peek at the timeout to prevent
-		 * a command from being retried forever.
-		 */
+	/*
+	 * Some LLDs, like scsi, peek at the timeout to prevent a
+	 * command from being retried forever.
+	 */
+	if (!req->timeout)
 		req->timeout = q->rq_timeout;
-	}
+
+	req->deadline = jiffies + req->timeout;
 	list_add_tail(&req->timeout_list, &q->timeout_list);
 
 	/*
 	 * If the timer isn't already pending or this timeout is earlier
-	 * than an existing one, modify the timer. Round to next nearest
+	 * than an existing one, modify the timer. Round up to next nearest
 	 * second.
 	 */
-	expiry = round_jiffies(req->deadline);
-
-	/*
-	 * We use ->deadline == 0 to detect whether a timer was added or
-	 * not, so just increase to next jiffy for that specific case
-	 */
-	if (unlikely(!req->deadline))
-		req->deadline = 1;
+	expiry = round_jiffies_up(req->deadline);
 
 	if (!timer_pending(&q->timeout) ||
 	    time_before(expiry, q->timeout.expires))
@@ -222,14 +205,34 @@ void blk_abort_queue(struct request_queue *q)
 {
 	unsigned long flags;
 	struct request *rq, *tmp;
+	LIST_HEAD(list);
+
+	/*
+	 * Not a request based block device, nothing to abort
+	 */
+	if (!q->request_fn)
+		return;
 
 	spin_lock_irqsave(q->queue_lock, flags);
 
 	elv_abort_queue(q);
 
-	list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list)
+	/*
+	 * Splice entries to local list, to avoid deadlocking if entries
+	 * get readded to the timeout list by error handling
+	 */
+	list_splice_init(&q->timeout_list, &list);
+
+	list_for_each_entry_safe(rq, tmp, &list, timeout_list)
 		blk_abort_request(rq);
 
+	/*
+	 * Occasionally, blk_abort_request() will return without
+	 * deleting the element from the list. Make sure we add those back
+	 * instead of leaving them on the local stack list.
+	 */
+	list_splice(&list, &q->timeout_list);
+
 	spin_unlock_irqrestore(q->queue_lock, flags);
 
 }