From: Ming Lei <ming.lei@canonical.com>
Date: Mon, 17 Aug 2015 02:31:47 +0000 (+0800)
Subject: block: loop: set QUEUE_FLAG_NOMERGES for request queue of loop
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5b5e20f421c0b6d437b3dec13e53674161998d56;p=linux-beck.git

block: loop: set QUEUE_FLAG_NOMERGES for request queue of loop

It doesn't make sense to enable merge because the I/O
submitted to backing file is handled page by page.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f9889b6bc02c..eee751032cad 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1595,6 +1595,12 @@ static int loop_add(struct loop_device **l, int i)
 	}
 	lo->lo_queue->queuedata = lo;
 
+	/*
+	 * It doesn't make sense to enable merge because the I/O
+	 * submitted to backing file is handled page by page.
+	 */
+	queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, lo->lo_queue);
+
 	INIT_LIST_HEAD(&lo->write_cmd_head);
 	INIT_WORK(&lo->write_work, loop_queue_write_work);