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

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.

Fixes: 83094e5e ("crypto: af_alg - add async support to...")
Cc: <stable@vger.kernel.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

crypto/algif_aead.c

@@ -78,7 +78,7 @@ static int crypto_aead_copy_sgl(struct crypto_sync_skcipher *null_tfm,
 	SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, null_tfm);
 
 	skcipher_request_set_sync_tfm(skreq, null_tfm);
-	skcipher_request_set_callback(skreq, CRYPTO_TFM_REQ_MAY_BACKLOG,
+	skcipher_request_set_callback(skreq, CRYPTO_TFM_REQ_MAY_SLEEP,
 				      NULL, NULL);
 	skcipher_request_set_crypt(skreq, src, dst, len, NULL);
 
@@ -291,19 +291,20 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 		areq->outlen = outlen;
 
 		aead_request_set_callback(&areq->cra_u.aead_req,
-					  CRYPTO_TFM_REQ_MAY_BACKLOG,
+					  CRYPTO_TFM_REQ_MAY_SLEEP,
 					  af_alg_async_cb, areq);
 		err = ctx->enc ? crypto_aead_encrypt(&areq->cra_u.aead_req) :
 				 crypto_aead_decrypt(&areq->cra_u.aead_req);
 
 		/* AIO operation in progress */
-		if (err == -EINPROGRESS || err == -EBUSY)
+		if (err == -EINPROGRESS)
 			return -EIOCBQUEUED;
 
 		sock_put(sk);
 	} else {
 		/* Synchronous operation */
 		aead_request_set_callback(&areq->cra_u.aead_req,
+					  CRYPTO_TFM_REQ_MAY_SLEEP |
 					  CRYPTO_TFM_REQ_MAY_BACKLOG,
 					  crypto_req_done, &ctx->wait);
 		err = crypto_wait_req(ctx->enc ?