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, 10 insertions, 5 deletions

diff --git a/block/ioctl.c b/block/ioctl.c
index 09fd7f1ef23a..d8052f0dabd3 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -114,8 +114,10 @@ static int blkdev_reread_part(struct block_device *bdev)
 }
 
 static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
-                             uint64_t len)
+                             uint64_t len, int secure)
 {
+        unsigned long flags = BLKDEV_IFL_WAIT;
+
         if (start & 511)
                 return -EINVAL;
         if (len & 511)
@@ -125,8 +127,9 @@ static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
 
         if (start + len > (bdev->bd_inode->i_size >> 9))
                 return -EINVAL;
-        return blkdev_issue_discard(bdev, start, len, GFP_KERNEL,
-                                    BLKDEV_IFL_WAIT);
+        if (secure)
+                flags |= BLKDEV_IFL_SECURE;
+        return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
 }
 
 static int put_ushort(unsigned long arg, unsigned short val)
@@ -213,7 +216,8 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
                 set_device_ro(bdev, n);
                 return 0;
 
-        case BLKDISCARD: {
+        case BLKDISCARD:
+        case BLKSECDISCARD: {
                 uint64_t range[2];
 
                 if (!(mode & FMODE_WRITE))
@@ -222,7 +226,8 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
                         return -EFAULT;
 
-                return blk_ioctl_discard(bdev, range[0], range[1]);
+                return blk_ioctl_discard(bdev, range[0], range[1],
+                                         cmd == BLKSECDISCARD);
         }
 
         case HDIO_GETGEO: {