netvsc: allow controlling send/recv buffer size

Control the size of the buffer areas via ethtool ring settings.
They aren't really traditional hardware rings, but host API breaks
receive and send buffer into chunks. The final size of the chunks are
controlled by the host.

The default value of send and receive buffer area for host DMA
is much larger than it needs to be. Experimentation shows that
4M receive and 1M send is sufficient.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 38 insertions, 32 deletions

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 7407006f4e22..d9d7555148eb 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -75,6 +75,10 @@ static struct netvsc_device *alloc_net_device(void)
 	atomic_set(&net_device->open_cnt, 0);
 	net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
 	net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
+
+	net_device->recv_section_size = NETVSC_RECV_SECTION_SIZE;
+	net_device->send_section_size = NETVSC_SEND_SECTION_SIZE;
+
 	init_completion(&net_device->channel_init_wait);
 	init_waitqueue_head(&net_device->subchan_open);
 
@@ -143,6 +147,7 @@ static void netvsc_destroy_buf(struct hv_device *device)
 				"revoke receive buffer to netvsp\n");
 			return;
 		}
+		net_device->recv_section_cnt = 0;
 	}
 
 	/* Teardown the gpadl on the vsp end */
@@ -173,7 +178,7 @@ static void netvsc_destroy_buf(struct hv_device *device)
 	 * NVSP_MSG1_TYPE_SEND_SEND_BUF msg) therefore, we need
 	 * to send a revoke msg here
 	 */
-	if (net_device->send_section_size) {
+	if (net_device->send_section_cnt) {
 		/* Send the revoke receive buffer */
 		revoke_packet = &net_device->revoke_packet;
 		memset(revoke_packet, 0, sizeof(struct nvsp_message));
@@ -205,6 +210,7 @@ static void netvsc_destroy_buf(struct hv_device *device)
 				   "revoke send buffer to netvsp\n");
 			return;
 		}
+		net_device->send_section_cnt = 0;
 	}
 	/* Teardown the gpadl on the vsp end */
 	if (net_device->send_buf_gpadl_handle) {
@@ -244,18 +250,25 @@ int netvsc_alloc_recv_comp_ring(struct netvsc_device *net_device, u32 q_idx)
 }
 
 static int netvsc_init_buf(struct hv_device *device,
-			   struct netvsc_device *net_device)
+			   struct netvsc_device *net_device,
+			   const struct netvsc_device_info *device_info)
 {
 	struct nvsp_1_message_send_receive_buffer_complete *resp;
 	struct net_device *ndev = hv_get_drvdata(device);
 	struct nvsp_message *init_packet;
+	unsigned int buf_size;
 	size_t map_words;
 	int ret = 0;
 
-	net_device->recv_buf = vzalloc(net_device->recv_buf_size);
+	/* Get receive buffer area. */
+	buf_size = device_info->recv_sections * net_device->recv_section_size;
+	buf_size = roundup(buf_size, PAGE_SIZE);
+
+	net_device->recv_buf = vzalloc(buf_size);
 	if (!net_device->recv_buf) {
-		netdev_err(ndev, "unable to allocate receive "
-			"buffer of size %d\n", net_device->recv_buf_size);
+		netdev_err(ndev,
+			   "unable to allocate receive buffer of size %u\n",
+			   buf_size);
 		ret = -ENOMEM;
 		goto cleanup;
 	}
@@ -266,7 +279,7 @@ static int netvsc_init_buf(struct hv_device *device,
 	 * than the channel to establish the gpadl handle.
 	 */
 	ret = vmbus_establish_gpadl(device->channel, net_device->recv_buf,
-				    net_device->recv_buf_size,
+				    buf_size,
 				    &net_device->recv_buf_gpadl_handle);
 	if (ret != 0) {
 		netdev_err(ndev,
@@ -312,31 +325,31 @@ static int netvsc_init_buf(struct hv_device *device,
 		   resp->num_sections, resp->sections[0].sub_alloc_size,
 		   resp->sections[0].num_sub_allocs);
 
-	net_device->recv_section_cnt = resp->num_sections;
-
-	/*
-	 * For 1st release, there should only be 1 section that represents the
-	 * entire receive buffer
-	 */
-	if (net_device->recv_section_cnt != 1 ||
-	    resp->sections[0].offset != 0) {
+	/* There should only be one section for the entire receive buffer */
+	if (resp->num_sections != 1 || resp->sections[0].offset != 0) {
 		ret = -EINVAL;
 		goto cleanup;
 	}
 
+	net_device->recv_section_size = resp->sections[0].sub_alloc_size;
+	net_device->recv_section_cnt = resp->sections[0].num_sub_allocs;
+
 	/* Setup receive completion ring */
 	net_device->recv_completion_cnt
-		= round_up(resp->sections[0].num_sub_allocs + 1,
+		= round_up(net_device->recv_section_cnt + 1,
 			   PAGE_SIZE / sizeof(u64));
 	ret = netvsc_alloc_recv_comp_ring(net_device, 0);
 	if (ret)
 		goto cleanup;
 
 	/* Now setup the send buffer. */
-	net_device->send_buf = vzalloc(net_device->send_buf_size);
+	buf_size = device_info->send_sections * net_device->send_section_size;
+	buf_size = round_up(buf_size, PAGE_SIZE);
+
+	net_device->send_buf = vzalloc(buf_size);
 	if (!net_device->send_buf) {
-		netdev_err(ndev, "unable to allocate send "
-			   "buffer of size %d\n", net_device->send_buf_size);
+		netdev_err(ndev, "unable to allocate send buffer of size %u\n",
+			   buf_size);
 		ret = -ENOMEM;
 		goto cleanup;
 	}
@@ -346,7 +359,7 @@ static int netvsc_init_buf(struct hv_device *device,
 	 * than the channel to establish the gpadl handle.
 	 */
 	ret = vmbus_establish_gpadl(device->channel, net_device->send_buf,
-				    net_device->send_buf_size,
+				    buf_size,
 				    &net_device->send_buf_gpadl_handle);
 	if (ret != 0) {
 		netdev_err(ndev,
@@ -391,10 +404,8 @@ static int netvsc_init_buf(struct hv_device *device,
 	net_device->send_section_size = init_packet->msg.
 				v1_msg.send_send_buf_complete.section_size;
 
-	/* Section count is simply the size divided by the section size.
-	 */
-	net_device->send_section_cnt =
-		net_device->send_buf_size / net_device->send_section_size;
+	/* Section count is simply the size divided by the section size. */
+	net_device->send_section_cnt = buf_size / net_device->send_section_size;
 
 	netdev_dbg(ndev, "Send section size: %d, Section count:%d\n",
 		   net_device->send_section_size, net_device->send_section_cnt);
@@ -472,7 +483,8 @@ static int negotiate_nvsp_ver(struct hv_device *device,
 }
 
 static int netvsc_connect_vsp(struct hv_device *device,
-			      struct netvsc_device *net_device)
+			      struct netvsc_device *net_device,
+			      const struct netvsc_device_info *device_info)
 {
 	const u32 ver_list[] = {
 		NVSP_PROTOCOL_VERSION_1, NVSP_PROTOCOL_VERSION_2,
@@ -522,14 +534,8 @@ static int netvsc_connect_vsp(struct hv_device *device,
 	if (ret != 0)
 		goto cleanup;
 
-	/* Post the big receive buffer to NetVSP */
-	if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_2)
-		net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE_LEGACY;
-	else
-		net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE;
-	net_device->send_buf_size = NETVSC_SEND_BUFFER_SIZE;
 
-	ret = netvsc_init_buf(device, net_device);
+	ret = netvsc_init_buf(device, net_device, device_info);
 
 cleanup:
 	return ret;
@@ -1287,7 +1293,7 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device,
 	rcu_assign_pointer(net_device_ctx->nvdev, net_device);
 
 	/* Connect with the NetVsp */
-	ret = netvsc_connect_vsp(device, net_device);
+	ret = netvsc_connect_vsp(device, net_device, device_info);
 	if (ret != 0) {
 		netdev_err(ndev,
 			"unable to connect to NetVSP - %d\n", ret);