crypto: algif_skcipher - Do not set MAY_BACKLOG on the async path

commit dad41997 upstream.

The async path cannot use MAY_BACKLOG because it is not meant to
block, which is what MAY_BACKLOG does.  On the other hand, both
the sync and async paths can make use of MAY_SLEEP.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

crypto/algif_skcipher.c

@@ -536,7 +536,7 @@ static int skcipher_recvmsg_async(struct socket *sock, struct msghdr *msg,
 	sg_init_table(sreq->tsg, tx_nents);
 	memcpy(iv, ctx->iv, ivsize);
 	skcipher_request_set_tfm(req, tfm);
-	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
 				      skcipher_async_cb, sreq);
 
 	while (iov_iter_count(&msg->msg_iter)) {
@@ -950,7 +950,8 @@ static int skcipher_accept_parent_nokey(void *private, struct sock *sk)
 	ask->private = ctx;
 
 	skcipher_request_set_tfm(&ctx->req, skcipher);
-	skcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+	skcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_SLEEP |
+						 CRYPTO_TFM_REQ_MAY_BACKLOG,
 				      af_alg_complete, &ctx->completion);
 
 	sk->sk_destruct = skcipher_sock_destruct;