dm crypt: tidy io ref counting
Make io reference counting more obvious.
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 986283c..44e1aa3 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -584,7 +584,6 @@
crypt_free_buffer_pages(cc, clone);
bio_put(clone);
io->error = -EIO;
- crypt_dec_pending(io);
return;
}
@@ -593,6 +592,9 @@
clone->bi_sector = cc->start + io->sector;
io->sector += bio_sectors(clone);
+
+ atomic_inc(&io->pending);
+ generic_make_request(clone);
}
static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
@@ -610,7 +612,6 @@
clone = crypt_alloc_buffer(io, remaining);
if (unlikely(!clone)) {
io->error = -ENOMEM;
- crypt_dec_pending(io);
return;
}
@@ -625,16 +626,6 @@
if (unlikely(r < 0))
return;
- /* Grab another reference to the io struct
- * before we kick off the request */
- if (remaining)
- atomic_inc(&io->pending);
-
- generic_make_request(clone);
-
- /* Do not reference clone after this - it
- * may be gone already. */
-
/* out of memory -> run queues */
if (unlikely(remaining))
congestion_wait(WRITE, HZ/100);
@@ -645,10 +636,15 @@
{
struct crypt_config *cc = io->target->private;
+ /*
+ * Prevent io from disappearing until this function completes.
+ */
atomic_inc(&io->pending);
crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
kcryptd_crypt_write_convert_loop(io);
+
+ crypt_dec_pending(io);
}
static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)