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authorBen Collins <ben.c@servergy.com>2015-04-03 16:09:46 +0000
committerMike Snitzer <snitzer@redhat.com>2015-04-15 12:10:26 -0400
commit0618764cb25f6fa9fb31152995de42a8a0496475 (patch)
tree16e5a37e6f584465d05c8df160a81e35609182a8
parent5977907937afa2b5584a874d44ba6c0f56aeaa9c (diff)
dm crypt: fix deadlock when async crypto algorithm returns -EBUSY
I suspect this doesn't show up for most anyone because software algorithms typically don't have a sense of being too busy. However, when working with the Freescale CAAM driver it will return -EBUSY on occasion under heavy -- which resulted in dm-crypt deadlock. After checking the logic in some other drivers, the scheme for crypt_convert() and it's callback, kcryptd_async_done(), were not correctly laid out to properly handle -EBUSY or -EINPROGRESS. Fix this by using the completion for both -EBUSY and -EINPROGRESS. Now crypt_convert()'s use of completion is comparable to af_alg_wait_for_completion(). Similarly, kcryptd_async_done() follows the pattern used in af_alg_complete(). Before this fix dm-crypt would lockup within 1-2 minutes running with the CAAM driver. Fix was regression tested against software algorithms on PPC32 and x86_64, and things seem perfectly happy there as well. Signed-off-by: Ben Collins <ben.c@servergy.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
-rw-r--r--drivers/md/dm-crypt.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index aa1238facbeb..9b5e1eb0ffcf 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -925,11 +925,10 @@ static int crypt_convert(struct crypt_config *cc,
switch (r) {
/* async */
+ case -EINPROGRESS:
case -EBUSY:
wait_for_completion(&ctx->restart);
reinit_completion(&ctx->restart);
- /* fall through*/
- case -EINPROGRESS:
ctx->req = NULL;
ctx->cc_sector++;
continue;
@@ -1346,10 +1345,8 @@ static void kcryptd_async_done(struct crypto_async_request *async_req,
struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
struct crypt_config *cc = io->cc;
- if (error == -EINPROGRESS) {
- complete(&ctx->restart);
+ if (error == -EINPROGRESS)
return;
- }
if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post)
error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq);
@@ -1360,12 +1357,15 @@ static void kcryptd_async_done(struct crypto_async_request *async_req,
crypt_free_req(cc, req_of_dmreq(cc, dmreq), io->base_bio);
if (!atomic_dec_and_test(&ctx->cc_pending))
- return;
+ goto done;
if (bio_data_dir(io->base_bio) == READ)
kcryptd_crypt_read_done(io);
else
kcryptd_crypt_write_io_submit(io, 1);
+done:
+ if (!completion_done(&ctx->restart))
+ complete(&ctx->restart);
}
static void kcryptd_crypt(struct work_struct *work)