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>

1 files changed, 6 insertions, 0 deletions

diff --git a/block/blk-lib.c b/block/blk-lib.c
index c1fc55a83ba1..c392029a104e 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -62,6 +62,12 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
                 max_discard_sectors &= ~(disc_sects - 1);
         }
 
+        if (flags & BLKDEV_IFL_SECURE) {
+                if (!blk_queue_secdiscard(q))
+                        return -EOPNOTSUPP;
+                type |= DISCARD_SECURE;
+        }
+
         while (nr_sects && !ret) {
                 bio = bio_alloc(gfp_mask, 1);
                 if (!bio) {