1 files changed, 40 insertions, 1 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index ad98ded3008..046ee516074 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -56,6 +56,7 @@ struct dm_crypt_io {
         atomic_t pending;
         int error;
         sector_t sector;
+        struct dm_crypt_io *base_io;
 };
 
 struct dm_crypt_request {
@@ -534,6 +535,7 @@ static struct dm_crypt_io *crypt_io_alloc(struct dm_target *ti,
         io->base_bio = bio;
         io->sector = sector;
         io->error = 0;
+        io->base_io = NULL;
         atomic_set(&io->pending, 0);
 
         return io;
@@ -547,6 +549,7 @@ static void crypt_inc_pending(struct dm_crypt_io *io)
 /*
  * One of the bios was finished. Check for completion of
  * the whole request and correctly clean up the buffer.
+ * If base_io is set, wait for the last fragment to complete.
  */
 static void crypt_dec_pending(struct dm_crypt_io *io)
 {
@@ -555,7 +558,14 @@ static void crypt_dec_pending(struct dm_crypt_io *io)
         if (!atomic_dec_and_test(&io->pending))
                 return;
 
-        bio_endio(io->base_bio, io->error);
+        if (likely(!io->base_io))
+                bio_endio(io->base_bio, io->error);
+        else {
+                if (io->error && !io->base_io->error)
+                        io->base_io->error = io->error;
+                crypt_dec_pending(io->base_io);
+        }
+
         mempool_free(io, cc->io_pool);
 }
 
@@ -699,6 +709,7 @@ static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
 {
         struct crypt_config *cc = io->target->private;
         struct bio *clone;
+        struct dm_crypt_io *new_io;
         int crypt_finished;
         unsigned out_of_pages = 0;
         unsigned remaining = io->base_bio->bi_size;
@@ -753,6 +764,34 @@ static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
                 if (unlikely(out_of_pages))
                         congestion_wait(WRITE, HZ/100);
 
+                /*
+                 * With async crypto it is unsafe to share the crypto context
+                 * between fragments, so switch to a new dm_crypt_io structure.
+                 */
+                if (unlikely(!crypt_finished && remaining)) {
+                        new_io = crypt_io_alloc(io->target, io->base_bio,
+                                                sector);
+                        crypt_inc_pending(new_io);
+                        crypt_convert_init(cc, &new_io->ctx, NULL,
+                                           io->base_bio, sector);
+                        new_io->ctx.idx_in = io->ctx.idx_in;
+                        new_io->ctx.offset_in = io->ctx.offset_in;
+
+                        /*
+                         * Fragments after the first use the base_io
+                         * pending count.
+                         */
+                        if (!io->base_io)
+                                new_io->base_io = io;
+                        else {
+                                new_io->base_io = io->base_io;
+                                crypt_inc_pending(io->base_io);
+                                crypt_dec_pending(io);
+                        }
+
+                        io = new_io;
+                }
+
                 if (unlikely(remaining))
                         wait_event(cc->writeq, !atomic_read(&io->ctx.pending));
         }