From: Jens Axboe <axboe@kernel.dk>
Date: Wed, 19 Oct 2011 12:30:42 +0000 (+0200)
Subject: Merge branch 'v3.1-rc10' into for-3.2/core
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5c04b426f2e8b46cfc7969a35b2631063a3c646c;p=linux-beck.git

Merge branch 'v3.1-rc10' into for-3.2/core

Conflicts:
	block/blk-core.c
	include/linux/blkdev.h

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

5c04b426f2e8b46cfc7969a35b2631063a3c646c
diff --cc block/blk-core.c
index 97e9e5405b83,d34433ae7917..79e41a76d96a
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@@ -1235,8 -1240,8 +1238,8 @@@ void blk_queue_bio(struct request_queu
  	 * Check if we can merge with the plugged list before grabbing
  	 * any locks.
  	 */
- 	if (attempt_plug_merge(current, q, bio))
+ 	if (attempt_plug_merge(current, q, bio, &request_count))
 -		goto out;
 +		return;
  
  	spin_lock_irq(q->queue_lock);
  
diff --cc drivers/md/raid1.c
index 97f2a5f977b1,d9587dffe533..d4ddfa627301
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@@ -1117,8 -1116,15 +1116,13 @@@ read_again
  		goto retry_write;
  	}
  
+ 	r1_bio_write_done(r1_bio);
+ 
+ 	/* In case raid1d snuck in to freeze_array */
+ 	wake_up(&conf->wait_barrier);
+ 
  	if (do_sync || !bitmap || !plugged)
  		md_wakeup_thread(mddev->thread);
 -
 -	return 0;
  }
  
  static void status(struct seq_file *seq, mddev_t *mddev)
diff --cc include/linux/blkdev.h
index 1978655faa3b,7fbaa9103344..0b68044e7abb
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@@ -860,23 -863,16 +865,22 @@@ struct request_queue *blk_alloc_queue_n
  extern void blk_put_queue(struct request_queue *);
  
  /*
 - * Note: Code in between changing the blk_plug list/cb_list or element of such
 - * lists is preemptable, but such code can't do sleep (or be very careful),
 - * otherwise data is corrupted. For details, please check schedule() where
 - * blk_schedule_flush_plug() is called.
 + * blk_plug permits building a queue of related requests by holding the I/O
 + * fragments for a short period. This allows merging of sequential requests
 + * into single larger request. As the requests are moved from a per-task list to
 + * the device's request_queue in a batch, this results in improved scalability
 + * as the lock contention for request_queue lock is reduced.
 + *
 + * It is ok not to disable preemption when adding the request to the plug list
 + * or when attempting a merge, because blk_schedule_flush_list() will only flush
 + * the plug list when the task sleeps by itself. For details, please see
 + * schedule() where blk_schedule_flush_plug() is called.
   */
  struct blk_plug {
 -	unsigned long magic;
 -	struct list_head list;
 -	struct list_head cb_list;
 -	unsigned int should_sort;
 +	unsigned long magic; /* detect uninitialized use-cases */
 +	struct list_head list; /* requests */
 +	struct list_head cb_list; /* md requires an unplug callback */
 +	unsigned int should_sort; /* list to be sorted before flushing? */
- 	unsigned int count; /* number of queued requests */
  };
  #define BLK_MAX_REQUEST_COUNT 16