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>

9 files changed, 45 insertions, 7 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: {
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 53691774d34e..ca83a97c9715 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -150,6 +150,7 @@ enum rq_flag_bits {
         __REQ_FLUSH,            /* request for cache flush */
         __REQ_IO_STAT,          /* account I/O stat */
         __REQ_MIXED_MERGE,      /* merge of different types, fail separately */
+        __REQ_SECURE,           /* secure discard (used with __REQ_DISCARD) */
         __REQ_NR_BITS,          /* stops here */
 };
 
@@ -190,5 +191,6 @@ enum rq_flag_bits {
 #define REQ_FLUSH               (1 << __REQ_FLUSH)
 #define REQ_IO_STAT             (1 << __REQ_IO_STAT)
 #define REQ_MIXED_MERGE         (1 << __REQ_MIXED_MERGE)
+#define REQ_SECURE              (1 << __REQ_SECURE)
 
 #endif /* __LINUX_BLK_TYPES_H */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 89c855c5655c..2c54906f678f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -389,6 +389,7 @@ struct request_queue
 #define QUEUE_FLAG_DISCARD     16       /* supports DISCARD */
 #define QUEUE_FLAG_NOXMERGES   17       /* No extended merges */
 #define QUEUE_FLAG_ADD_RANDOM  18       /* Contributes to random pool */
+#define QUEUE_FLAG_SECDISCARD  19       /* supports SECDISCARD */
 
 #define QUEUE_FLAG_DEFAULT      ((1 << QUEUE_FLAG_IO_STAT) |            \
                                  (1 << QUEUE_FLAG_CLUSTER) |            \
@@ -524,6 +525,8 @@ enum {
 #define blk_queue_stackable(q)  \
         test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 #define blk_queue_discard(q)    test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
+#define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
+        test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
 
 #define blk_noretry_request(rq) \
         ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
@@ -918,10 +921,12 @@ static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 }
 enum{
         BLKDEV_WAIT,    /* wait for completion */
-        BLKDEV_BARRIER, /*issue request with barrier */
+        BLKDEV_BARRIER, /* issue request with barrier */
+        BLKDEV_SECURE,  /* secure discard */
 };
 #define BLKDEV_IFL_WAIT         (1 << BLKDEV_WAIT)
 #define BLKDEV_IFL_BARRIER      (1 << BLKDEV_BARRIER)
+#define BLKDEV_IFL_SECURE       (1 << BLKDEV_SECURE)
 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *,
                         unsigned long);
 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 267d02630517..7a0625e26a39 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -174,6 +174,7 @@ struct inodes_stat_t {
  */
 #define DISCARD_NOBARRIER       (WRITE | REQ_DISCARD)
 #define DISCARD_BARRIER         (WRITE | REQ_DISCARD | REQ_HARDBARRIER)
+#define DISCARD_SECURE          (DISCARD_NOBARRIER | REQ_SECURE)
 
 #define SEL_IN          1
 #define SEL_OUT         2
@@ -317,6 +318,7 @@ struct inodes_stat_t {
 #define BLKALIGNOFF _IO(0x12,122)
 #define BLKPBSZGET _IO(0x12,123)
 #define BLKDISCARDZEROES _IO(0x12,124)
+#define BLKSECDISCARD _IO(0x12,125)
 
 #define BMAP_IOCTL 1            /* obsolete - kept for compatibility */
 #define FIBMAP     _IO(0x00,1)  /* bmap access */
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 82499a5bdcb7..959f8d6c8cc1 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -710,6 +710,9 @@ static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
         if (rq->cmd_flags & REQ_DISCARD)
                 rw |= REQ_DISCARD;
 
+        if (rq->cmd_flags & REQ_SECURE)
+                rw |= REQ_SECURE;
+
         if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
                 what |= BLK_TC_ACT(BLK_TC_PC);
                 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
@@ -1816,6 +1819,8 @@ void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
                 rwbs[i++] = 'S';
         if (rw & REQ_META)
                 rwbs[i++] = 'M';
+        if (rw & REQ_SECURE)
+                rwbs[i++] = 'E';
 
         rwbs[i] = '\0';
 }
@@ -1828,6 +1833,9 @@ void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
         if (rq->cmd_flags & REQ_DISCARD)
                 rw |= REQ_DISCARD;
 
+        if (rq->cmd_flags & REQ_SECURE)
+                rw |= REQ_SECURE;
+
         bytes = blk_rq_bytes(rq);
 
         blk_fill_rwbs(rwbs, rw, bytes);