From 8d57a98ccd0b4489003473979da8f5a1363ba7a3 Mon Sep 17 00:00:00 2001
From: Adrian Hunter <adrian.hunter@nokia.com>
Date: Wed, 11 Aug 2010 14:17:49 -0700
Subject: block: add secure discard

Secure discard is the same as discard except that all copies of the
discarded sectors (perhaps created by garbage collection) must also be
erased.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 block/elevator.c | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'block/elevator.c')

diff --git a/block/elevator.c b/block/elevator.c
index 816a7c8..ec585c9 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -83,6 +83,12 @@ int elv_rq_merge_ok(struct request *rq, struct bio *bio)
 		return 0;
 
 	/*
+	 * Don't merge discard requests and secure discard requests
+	 */
+	if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE))
+		return 0;
+
+	/*
 	 * different data direction or already started, don't merge
 	 */
 	if (bio_data_dir(bio) != rq_data_dir(rq))
-- 
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