dm crypt: fix call to clone_init

Call clone_init early

We need to call clone_init as early as possible - at least before call
bio_put(clone) in any error path.  Otherwise, the destructor will try to
dereference bi_private, which may still be NULL.

Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 8527827b24f1..db439363f97d 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -107,6 +107,8 @@ struct crypt_config {
 
 static struct kmem_cache *_crypt_io_pool;
 
+static void clone_init(struct crypt_io *, struct bio *);
+
 /*
  * Different IV generation algorithms:
  *
@@ -379,9 +381,10 @@ static int crypt_convert(struct crypt_config *cc,
  * May return a smaller bio when running out of pages
  */
 static struct bio *
-crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
+crypt_alloc_buffer(struct crypt_io *io, unsigned int size,
                    struct bio *base_bio, unsigned int *bio_vec_idx)
 {
+        struct crypt_config *cc = io->target->private;
         struct bio *clone;
         unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
         gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
@@ -396,7 +399,7 @@ crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
         if (!clone)
                 return NULL;
 
-        clone->bi_destructor = dm_crypt_bio_destructor;
+        clone_init(io, clone);
 
         /* if the last bio was not complete, continue where that one ended */
         clone->bi_idx = *bio_vec_idx;
@@ -562,6 +565,7 @@ static void clone_init(struct crypt_io *io, struct bio *clone)
         clone->bi_end_io  = crypt_endio;
         clone->bi_bdev    = cc->dev->bdev;
         clone->bi_rw      = io->base_bio->bi_rw;
+        clone->bi_destructor = dm_crypt_bio_destructor;
 }
 
 static void process_read(struct crypt_io *io)
@@ -585,7 +589,6 @@ static void process_read(struct crypt_io *io)
         }
 
         clone_init(io, clone);
-        clone->bi_destructor = dm_crypt_bio_destructor;
         clone->bi_idx = 0;
         clone->bi_vcnt = bio_segments(base_bio);
         clone->bi_size = base_bio->bi_size;
@@ -615,7 +618,7 @@ static void process_write(struct crypt_io *io)
          * so repeat the whole process until all the data can be handled.
          */
         while (remaining) {
-                clone = crypt_alloc_buffer(cc, base_bio->bi_size,
+                clone = crypt_alloc_buffer(io, base_bio->bi_size,
                                            io->first_clone, &bvec_idx);
                 if (unlikely(!clone)) {
                         dec_pending(io, -ENOMEM);
@@ -631,7 +634,6 @@ static void process_write(struct crypt_io *io)
                         return;
                 }
 
-                clone_init(io, clone);
                 clone->bi_sector = cc->start + sector;
 
                 if (!io->first_clone) {