Commit 123111ea authored by Stefan Metzmacher's avatar Stefan Metzmacher Committed by Steve French
Browse files

smb: client: make use of smbdirect_socket.send_io.lcredits.* 



This makes the logic to prevent on overflow of
the send submission queue with ib_post_send() easier.

As we first get a local credit and then a remote credit
before we mark us as pending.

For now we'll keep the logic around smbdirect_socket.send_io.pending.*,
but that will likely change or be removed completely.

The server will get a similar logic soon, so
we'll be able to share the send code in future.

Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Long Li <longli@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: default avatarStefan Metzmacher <metze@samba.org>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 0158e864

fs/smb/client/smbdirect.c

+42 −25
Original line number Diff line number Diff line
@@ -172,6 +172,7 @@ static void smbd_disconnect_wake_up_all(struct smbdirect_socket *sc) 
	 * in order to notice the broken connection.

	 */

	wake_up_all(&sc->status_wait);

	wake_up_all(&sc->send_io.lcredits.wait_queue);

	wake_up_all(&sc->send_io.credits.wait_queue);

	wake_up_all(&sc->send_io.pending.dec_wait_queue);

	wake_up_all(&sc->send_io.pending.zero_wait_queue);
@@ -495,6 +496,7 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc) 
	struct smbdirect_send_io *request =

		container_of(wc->wr_cqe, struct smbdirect_send_io, cqe);

	struct smbdirect_socket *sc = request->socket;

	int lcredits = 0;



	log_rdma_send(INFO, "smbdirect_send_io 0x%p completed wc->status=%s\n",

		request, ib_wc_status_msg(wc->status));
@@ -504,22 +506,24 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc) 
			request->sge[i].addr,

			request->sge[i].length,

			DMA_TO_DEVICE);

	mempool_free(request, sc->send_io.mem.pool);

	lcredits += 1;



	if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_SEND) {

		if (wc->status != IB_WC_WR_FLUSH_ERR)

			log_rdma_send(ERR, "wc->status=%s wc->opcode=%d\n",

				ib_wc_status_msg(wc->status), wc->opcode);

		mempool_free(request, sc->send_io.mem.pool);

		smbd_disconnect_rdma_connection(sc);

		return;

	}



	atomic_add(lcredits, &sc->send_io.lcredits.count);

	wake_up(&sc->send_io.lcredits.wait_queue);



	if (atomic_dec_and_test(&sc->send_io.pending.count))

		wake_up(&sc->send_io.pending.zero_wait_queue);



	wake_up(&sc->send_io.pending.dec_wait_queue);



	mempool_free(request, sc->send_io.mem.pool);

}



static void dump_smbdirect_negotiate_resp(struct smbdirect_negotiate_resp *resp)
@@ -567,6 +571,7 @@ static bool process_negotiation_response( 
		log_rdma_event(ERR, "error: credits_granted==0\n");

		return false;

	}

	atomic_set(&sc->send_io.lcredits.count, sp->send_credit_target);

	atomic_set(&sc->send_io.credits.count, le16_to_cpu(packet->credits_granted));



	if (le32_to_cpu(packet->preferred_send_size) > sp->max_recv_size) {
@@ -1114,6 +1119,24 @@ static int smbd_post_send_iter(struct smbdirect_socket *sc, 
	struct smbdirect_data_transfer *packet;

	int new_credits = 0;



wait_lcredit:

	/* Wait for local send credits */

	rc = wait_event_interruptible(sc->send_io.lcredits.wait_queue,

		atomic_read(&sc->send_io.lcredits.count) > 0 ||

		sc->status != SMBDIRECT_SOCKET_CONNECTED);

	if (rc)

		goto err_wait_lcredit;



	if (sc->status != SMBDIRECT_SOCKET_CONNECTED) {

		log_outgoing(ERR, "disconnected not sending on wait_credit\n");

		rc = -EAGAIN;

		goto err_wait_lcredit;

	}

	if (unlikely(atomic_dec_return(&sc->send_io.lcredits.count) < 0)) {

		atomic_inc(&sc->send_io.lcredits.count);

		goto wait_lcredit;

	}



wait_credit:

	/* Wait for send credits. A SMBD packet needs one credit */

	rc = wait_event_interruptible(sc->send_io.credits.wait_queue,
@@ -1132,23 +1155,6 @@ static int smbd_post_send_iter(struct smbdirect_socket *sc, 
		goto wait_credit;

	}



wait_send_queue:

	wait_event(sc->send_io.pending.dec_wait_queue,

		atomic_read(&sc->send_io.pending.count) < sp->send_credit_target ||

		sc->status != SMBDIRECT_SOCKET_CONNECTED);



	if (sc->status != SMBDIRECT_SOCKET_CONNECTED) {

		log_outgoing(ERR, "disconnected not sending on wait_send_queue\n");

		rc = -EAGAIN;

		goto err_wait_send_queue;

	}



	if (unlikely(atomic_inc_return(&sc->send_io.pending.count) >

				sp->send_credit_target)) {

		atomic_dec(&sc->send_io.pending.count);

		goto wait_send_queue;

	}



	request = mempool_alloc(sc->send_io.mem.pool, GFP_KERNEL);

	if (!request) {

		rc = -ENOMEM;
@@ -1229,10 +1235,21 @@ static int smbd_post_send_iter(struct smbdirect_socket *sc, 
		     le32_to_cpu(packet->data_length),

		     le32_to_cpu(packet->remaining_data_length));



	/*

	 * Now that we got a local and a remote credit

	 * we add us as pending

	 */

	atomic_inc(&sc->send_io.pending.count);



	rc = smbd_post_send(sc, request);

	if (!rc)

		return 0;



	if (atomic_dec_and_test(&sc->send_io.pending.count))

		wake_up(&sc->send_io.pending.zero_wait_queue);



	wake_up(&sc->send_io.pending.dec_wait_queue);



err_dma:

	for (i = 0; i < request->num_sge; i++)

		if (request->sge[i].addr)
@@ -1246,14 +1263,14 @@ static int smbd_post_send_iter(struct smbdirect_socket *sc, 
	atomic_sub(new_credits, &sc->recv_io.credits.count);



err_alloc:

	if (atomic_dec_and_test(&sc->send_io.pending.count))

		wake_up(&sc->send_io.pending.zero_wait_queue);



err_wait_send_queue:

	/* roll back send credits and pending */

	atomic_inc(&sc->send_io.credits.count);

	wake_up(&sc->send_io.credits.wait_queue);



err_wait_credit:

	atomic_inc(&sc->send_io.lcredits.count);

	wake_up(&sc->send_io.lcredits.wait_queue);



err_wait_lcredit:

	return rc;

}