crypto: marvell - Don't chain at DMA level when backlog is disabled

The flag CRYPTO_TFM_REQ_MAY_BACKLOG is optional and can be set from the
user to put requests into the backlog queue when the main cryptographic
queue is full. Before calling mv_cesa_tdma_chain we must check the value
of the return status to be sure that the current request has been
correctly queued or added to the backlog.

Fixes: 85030c5168f1 ("crypto: marvell - Add support for chaining...")
Signed-off-by: Romain Perier <romain.perier@free-electrons.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/marvell/cesa.c

@@ -180,10 +180,11 @@ int mv_cesa_queue_req(struct crypto_async_request *req,
 	struct mv_cesa_engine *engine = creq->engine;
 
 	spin_lock_bh(&engine->lock);
-	if (mv_cesa_req_get_type(creq) == CESA_DMA_REQ)
-		mv_cesa_tdma_chain(engine, creq);
-
 	ret = crypto_enqueue_request(&engine->queue, req);
+	if ((mv_cesa_req_get_type(creq) == CESA_DMA_REQ) &&
+	    (ret == -EINPROGRESS ||
+	    (ret == -EBUSY && req->flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
+		mv_cesa_tdma_chain(engine, creq);
 	spin_unlock_bh(&engine->lock);
 
 	if (ret != -EINPROGRESS)