dm crypt: fix async inc_pending
The pending reference count must be incremented *before* the async work is
queued to another thread, not after. Otherwise there's a race if the
work completes and decrements the reference count before it gets incremented.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index d8126ac..262ed18 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -719,16 +719,15 @@
remaining -= clone->bi_size;
+ crypt_inc_pending(io);
r = crypt_convert(cc, &io->ctx);
if (atomic_dec_and_test(&io->ctx.pending)) {
/* processed, no running async crypto */
- crypt_inc_pending(io);
kcryptd_crypt_write_io_submit(io, r, 0);
if (unlikely(r < 0))
break;
- } else
- crypt_inc_pending(io);
+ }
/* out of memory -> run queues */
if (unlikely(remaining)) {