From: Jens Axboe <jaxboe@fusionio.com>
Date: Fri, 20 May 2011 18:36:16 +0000 (+0200)
Subject: Merge branch 'for-linus' into for-2.6.40/core
X-Git-Tag: v3.0-rc1~163^2~11
X-Git-Url: http://pileus.org/git/?p=~andy%2Flinux;a=commitdiff_plain;h=0eb8e885726a3a93206510092bbc7e39e272f6ef

Merge branch 'for-linus' into for-2.6.40/core

This patch merges in a fix that missed 2.6.39 final.

Conflicts:
	block/blk.h
---

0eb8e885726a3a93206510092bbc7e39e272f6ef
diff --cc block/blk.h
index 1f798b5a6f1,4df474d37e6..d6586287adc
--- a/block/blk.h
+++ b/block/blk.h
@@@ -61,27 -61,9 +61,29 @@@ static inline struct request *__elv_nex
  			rq = list_entry_rq(q->queue_head.next);
  			return rq;
  		}
+ 
 +		/*
 +		 * Flush request is running and flush request isn't queueable
 +		 * in the drive, we can hold the queue till flush request is
 +		 * finished. Even we don't do this, driver can't dispatch next
 +		 * requests and will requeue them. And this can improve
 +		 * throughput too. For example, we have request flush1, write1,
 +		 * flush 2. flush1 is dispatched, then queue is hold, write1
 +		 * isn't inserted to queue. After flush1 is finished, flush2
 +		 * will be dispatched. Since disk cache is already clean,
 +		 * flush2 will be finished very soon, so looks like flush2 is
 +		 * folded to flush1.
 +		 * Since the queue is hold, a flag is set to indicate the queue
 +		 * should be restarted later. Please see flush_end_io() for
 +		 * details.
 +		 */
 +		if (q->flush_pending_idx != q->flush_running_idx &&
 +				!queue_flush_queueable(q)) {
 +			q->flush_queue_delayed = 1;
 +			return NULL;
 +		}
- 		if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
+ 		if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
+ 		    !q->elevator->ops->elevator_dispatch_fn(q, 0))
  			return NULL;
  	}
  }