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>

5 files changed, 27 insertions, 6 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 7da630e25ae7..ee1a1e7e63cc 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1514,7 +1514,10 @@ static inline void __generic_make_request(struct bio *bio)
                 if (bio_check_eod(bio, nr_sectors))
                         goto end_io;
 
-                if ((bio->bi_rw & REQ_DISCARD) && !blk_queue_discard(q)) {
+                if ((bio->bi_rw & REQ_DISCARD) &&
+                    (!blk_queue_discard(q) ||
+                     ((bio->bi_rw & REQ_SECURE) &&
+                      !blk_queue_secdiscard(q)))) {
                         err = -EOPNOTSUPP;
                         goto end_io;
                 }
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) {
diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
index d53085637731..119f07b74dc0 100644
--- a/block/compat_ioctl.c
+++ b/block/compat_ioctl.c
@@ -703,6 +703,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
         case BLKFLSBUF:
         case BLKROSET:
         case BLKDISCARD:
+        case BLKSECDISCARD:
         /*
          * the ones below are implemented in blkdev_locked_ioctl,
          * but we call blkdev_ioctl, which gets the lock for us
diff --git a/block/elevator.c b/block/elevator.c
index 816a7c8d6394..ec585c9554d3 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))
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: {