[PATCH net-next 0/6] hv_netvsc: minor optimizations

@@ -1425,32 +1425,6 @@ struct rndis_message {
 	(sizeof(msg) + (sizeof(struct rndis_message) -	\
 	 sizeof(union rndis_message_container)))
 
-/* get pointer to info buffer with message pointer */
-#define MESSAGE_TO_INFO_BUFFER(msg)				\
-	(((unsigned char *)(msg)) + msg->info_buf_offset)
-
-/* get pointer to status buffer with message pointer */
-#define MESSAGE_TO_STATUS_BUFFER(msg)			\
-	(((unsigned char *)(msg)) + msg->status_buf_offset)
-
-/* get pointer to OOBD buffer with message pointer */
-#define MESSAGE_TO_OOBD_BUFFER(msg)				\
-	(((unsigned char *)(msg)) + msg->oob_data_offset)
-
-/* get pointer to data buffer with message pointer */
-#define MESSAGE_TO_DATA_BUFFER(msg)				\
-	(((unsigned char *)(msg)) + msg->per_pkt_info_offset)
-
-/* get pointer to contained message from NDIS_MESSAGE pointer */
-#define RNDIS_MESSAGE_PTR_TO_MESSAGE_PTR(rndis_msg)		\
-	((void *) &rndis_msg->msg)
-
-/* get pointer to contained message from NDIS_MESSAGE pointer */
-#define RNDIS_MESSAGE_RAW_PTR_TO_MESSAGE_PTR(rndis_msg)	\
-	((void *) rndis_msg)
-
-
-
 #define RNDIS_HEADER_SIZE	(sizeof(struct rndis_message) - \
 				 sizeof(union rndis_message_container))
 

@@ -712,11 +712,12 @@ static u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,
 	int i;
 	u32 msg_size = 0;
 	u32 padding = 0;
-	u32 remain = packet->total_data_buflen % net_device->pkt_align;
 	u32 page_count = packet->cp_partial ? packet->rmsg_pgcnt :
 		packet->page_buf_cnt;
+	u32 remain;
 
 	/* Add padding */
+	remain = packet->total_data_buflen & (net_device->pkt_align - 1);
 	if (skb->xmit_more && remain && !packet->cp_partial) {
 		padding = net_device->pkt_align - remain;
 		rndis_msg->msg_len += padding;

@@ -146,7 +146,6 @@ struct hv_netvsc_packet {
 
 struct netvsc_device_info {
 	unsigned char mac_adr[ETH_ALEN];
-	int  ring_size;
 	u32  num_chn;
 	u32  send_sections;
 	u32  recv_sections;

@@ -188,6 +187,9 @@ struct rndis_message;
 struct netvsc_device;
 struct net_device_context;
 
+extern u32 netvsc_ring_bytes;
+extern struct reciprocal_value netvsc_ring_reciprocal;
+
 struct netvsc_device *netvsc_device_add(struct hv_device *device,
 					const struct netvsc_device_info *info);
 int netvsc_alloc_recv_comp_ring(struct netvsc_device *net_device, u32 q_idx);

@@ -804,8 +806,6 @@ struct netvsc_device {
 
 	struct rndis_device *extension;
 
-	int ring_size;
-
 	u32 max_pkt; /* max number of pkt in one send, e.g. 8 */
 	u32 pkt_align; /* alignment bytes, e.g. 8 */
 

@@ -31,6 +31,7 @@
 #include <linux/vmalloc.h>
 #include <linux/rtnetlink.h>
 #include <linux/prefetch.h>
+#include <linux/reciprocal_div.h>
 
 #include <asm/sync_bitops.h>
 

@@ -588,14 +589,11 @@ void netvsc_device_remove(struct hv_device *device)
  * Get the percentage of available bytes to write in the ring.
  * The return value is in range from 0 to 100.
  */
-static inline u32 hv_ringbuf_avail_percent(
-		struct hv_ring_buffer_info *ring_info)
+static u32 hv_ringbuf_avail_percent(const struct hv_ring_buffer_info *ring_info)
 {
-	u32 avail_read, avail_write;
+	u32 avail_write = hv_get_bytes_to_write(ring_info);
 
-	hv_get_ringbuffer_availbytes(ring_info, &avail_read, &avail_write);
-
-	return avail_write * 100 / ring_info->ring_datasize;
+	return reciprocal_divide(avail_write  * 100, netvsc_ring_reciprocal);
 }
 
 static inline void netvsc_free_send_slot(struct netvsc_device *net_device,

@@ -1249,7 +1247,6 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device,
 				const struct netvsc_device_info *device_info)
 {
 	int i, ret = 0;
-	int ring_size = device_info->ring_size;
 	struct netvsc_device *net_device;
 	struct net_device *ndev = hv_get_drvdata(device);
 	struct net_device_context *net_device_ctx = netdev_priv(ndev);

@@ -1261,8 +1258,6 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device,
 	for (i = 0; i < VRSS_SEND_TAB_SIZE; i++)
 		net_device_ctx->tx_table[i] = 0;
 
-	net_device->ring_size = ring_size;
-
 	/* Because the device uses NAPI, all the interrupt batching and
 	 * control is done via Net softirq, not the channel handling
 	 */

@@ -1289,10 +1284,9 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device,
 		       netvsc_poll, NAPI_POLL_WEIGHT);
 
 	/* Open the channel */
-	ret = vmbus_open(device->channel, ring_size * PAGE_SIZE,
-			 ring_size * PAGE_SIZE, NULL, 0,
-			 netvsc_channel_cb,
-			 net_device->chan_table);
+	ret = vmbus_open(device->channel, netvsc_ring_bytes,
+			 netvsc_ring_bytes,  NULL, 0,
+			 netvsc_channel_cb, net_device->chan_table);
 
 	if (ret != 0) {
 		netif_napi_del(&net_device->chan_table[0].napi);

@@ -35,6 +35,7 @@
 #include <linux/slab.h>
 #include <linux/rtnetlink.h>
 #include <linux/netpoll.h>
+#include <linux/reciprocal_div.h>
 
 #include <net/arp.h>
 #include <net/route.h>

@@ -54,9 +55,11 @@
 #define LINKCHANGE_INT (2 * HZ)
 #define VF_TAKEOVER_INT (HZ / 10)
 
-static int ring_size = 128;
-module_param(ring_size, int, S_IRUGO);
+static unsigned int ring_size __ro_after_init = 128;
+module_param(ring_size, uint, S_IRUGO);
 MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
+unsigned int netvsc_ring_bytes __ro_after_init;
+struct reciprocal_value netvsc_ring_reciprocal __ro_after_init;
 
 static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE |
 				NETIF_MSG_LINK | NETIF_MSG_IFUP |

@@ -860,7 +863,6 @@ static int netvsc_set_channels(struct net_device *net,
 
 	memset(&device_info, 0, sizeof(device_info));
 	device_info.num_chn = count;
-	device_info.ring_size = ring_size;
 	device_info.send_sections = nvdev->send_section_cnt;
 	device_info.send_section_size = nvdev->send_section_size;
 	device_info.recv_sections = nvdev->recv_section_cnt;

@@ -975,7 +977,6 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
 		rndis_filter_close(nvdev);
 
 	memset(&device_info, 0, sizeof(device_info));
-	device_info.ring_size = ring_size;
 	device_info.num_chn = nvdev->num_chn;
 	device_info.send_sections = nvdev->send_section_cnt;
 	device_info.send_section_size = nvdev->send_section_size;

@@ -1539,7 +1540,6 @@ static int netvsc_set_ringparam(struct net_device *ndev,
 
 	memset(&device_info, 0, sizeof(device_info));
 	device_info.num_chn = nvdev->num_chn;
-	device_info.ring_size = ring_size;
 	device_info.send_sections = new_tx;
 	device_info.send_section_size = nvdev->send_section_size;
 	device_info.recv_sections = new_rx;

@@ -1995,7 +1995,6 @@ static int netvsc_probe(struct hv_device *dev,
 
 	/* Notify the netvsc driver of the new device */
 	memset(&device_info, 0, sizeof(device_info));
-	device_info.ring_size = ring_size;
 	device_info.num_chn = VRSS_CHANNEL_DEFAULT;
 	device_info.send_sections = NETVSC_DEFAULT_TX;
 	device_info.send_section_size = NETVSC_SEND_SECTION_SIZE;

@@ -2158,11 +2157,13 @@ static int __init netvsc_drv_init(void)
 
 	if (ring_size < RING_SIZE_MIN) {
 		ring_size = RING_SIZE_MIN;
-		pr_info("Increased ring_size to %d (min allowed)\n",
+		pr_info("Increased ring_size to %u (min allowed)\n",
 			ring_size);
 	}
-	ret = vmbus_driver_register(&netvsc_drv);
+	netvsc_ring_bytes = ring_size * PAGE_SIZE;
+	netvsc_ring_reciprocal = reciprocal_value(netvsc_ring_bytes);
 
+	ret = vmbus_driver_register(&netvsc_drv);
 	if (ret)
 		return ret;
 

@@ -1040,8 +1040,8 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
 	/* Set the channel before opening.*/
 	nvchan->channel = new_sc;
 
-	ret = vmbus_open(new_sc, nvscdev->ring_size * PAGE_SIZE,
-			 nvscdev->ring_size * PAGE_SIZE, NULL, 0,
+	ret = vmbus_open(new_sc, netvsc_ring_bytes,
+			 netvsc_ring_bytes, NULL, 0,
 			 netvsc_channel_cb, nvchan);
 	if (ret == 0)
 		napi_enable(&nvchan->napi);

@@ -177,17 +177,15 @@ static int netvsc_close(struct net_device *net)
 	return ret;
 }
 
-static void *init_ppi_data(struct rndis_message *msg, u32 ppi_size,
-			   int pkt_type)
+static inline void *init_ppi_data(struct rndis_message *msg,
+				  u32 ppi_size, u32 pkt_type)
 {
-	struct rndis_packet *rndis_pkt;
+	struct rndis_packet *rndis_pkt = &msg->msg.pkt;
 	struct rndis_per_packet_info *ppi;
 
-	rndis_pkt = &msg->msg.pkt;
 	rndis_pkt->data_offset += ppi_size;
-
-	ppi = (struct rndis_per_packet_info *)((void *)rndis_pkt +
-		rndis_pkt->per_pkt_info_offset + rndis_pkt->per_pkt_info_len);
+	ppi = (void *)rndis_pkt + rndis_pkt->per_pkt_info_offset
+		+ rndis_pkt->per_pkt_info_len;
 
 	ppi->size = ppi_size;
 	ppi->type = pkt_type;

@@ -195,7 +193,7 @@ static void *init_ppi_data(struct rndis_message *msg, u32 ppi_size,
 
 	rndis_pkt->per_pkt_info_len += ppi_size;
 
-	return ppi;
+	return ppi + 1;
 }
 
 /* Azure hosts don't support non-TCP port numbers in hashing for fragmented

@@ -472,10 +470,8 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 	int ret;
 	unsigned int num_data_pgs;
 	struct rndis_message *rndis_msg;
-	struct rndis_packet *rndis_pkt;
 	struct net_device *vf_netdev;
 	u32 rndis_msg_size;
-	struct rndis_per_packet_info *ppi;
 	u32 hash;
 	struct hv_page_buffer pb[MAX_PAGE_BUFFER_COUNT];
 

@@ -530,34 +526,36 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 
 	rndis_msg = (struct rndis_message *)skb->head;
 
-	memset(rndis_msg, 0, RNDIS_AND_PPI_SIZE);
-
 	/* Add the rndis header */
 	rndis_msg->ndis_msg_type = RNDIS_MSG_PACKET;
 	rndis_msg->msg_len = packet->total_data_buflen;
-	rndis_pkt = &rndis_msg->msg.pkt;
-	rndis_pkt->data_offset = sizeof(struct rndis_packet);
-	rndis_pkt->data_len = packet->total_data_buflen;
-	rndis_pkt->per_pkt_info_offset = sizeof(struct rndis_packet);
+
+	rndis_msg->msg.pkt = (struct rndis_packet) {
+		.data_offset = sizeof(struct rndis_packet),
+		.data_len = packet->total_data_buflen,
+		.per_pkt_info_offset = sizeof(struct rndis_packet),
+	};
 
 	rndis_msg_size = RNDIS_MESSAGE_SIZE(struct rndis_packet);
 
 	hash = skb_get_hash_raw(skb);
 	if (hash != 0 && net->real_num_tx_queues > 1) {
+		u32 *hash_info;
+
 		rndis_msg_size += NDIS_HASH_PPI_SIZE;
-		ppi = init_ppi_data(rndis_msg, NDIS_HASH_PPI_SIZE,
-				    NBL_HASH_VALUE);
-		*(u32 *)((void *)ppi + ppi->ppi_offset) = hash;
+		hash_info = init_ppi_data(rndis_msg, NDIS_HASH_PPI_SIZE,
+					  NBL_HASH_VALUE);
+		*hash_info = hash;
 	}
 
 	if (skb_vlan_tag_present(skb)) {
 		struct ndis_pkt_8021q_info *vlan;
 
 		rndis_msg_size += NDIS_VLAN_PPI_SIZE;
-		ppi = init_ppi_data(rndis_msg, NDIS_VLAN_PPI_SIZE,
-				    IEEE_8021Q_INFO);
+		vlan = init_ppi_data(rndis_msg, NDIS_VLAN_PPI_SIZE,
+				     IEEE_8021Q_INFO);
 
-		vlan = (void *)ppi + ppi->ppi_offset;
+		vlan->value = 0;
 		vlan->vlanid = skb->vlan_tci & VLAN_VID_MASK;
 		vlan->pri = (skb->vlan_tci & VLAN_PRIO_MASK) >>
 				VLAN_PRIO_SHIFT;

@@ -567,11 +565,10 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 		struct ndis_tcp_lso_info *lso_info;
 
 		rndis_msg_size += NDIS_LSO_PPI_SIZE;
-		ppi = init_ppi_data(rndis_msg, NDIS_LSO_PPI_SIZE,
-				    TCP_LARGESEND_PKTINFO);
-
-		lso_info = (void *)ppi + ppi->ppi_offset;
+		lso_info = init_ppi_data(rndis_msg, NDIS_LSO_PPI_SIZE,
+					 TCP_LARGESEND_PKTINFO);
 
+		lso_info->value = 0;
 		lso_info->lso_v2_transmit.type = NDIS_TCP_LARGE_SEND_OFFLOAD_V2_TYPE;
 		if (skb->protocol == htons(ETH_P_IP)) {
 			lso_info->lso_v2_transmit.ip_version =

@@ -596,12 +593,10 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 			struct ndis_tcp_ip_checksum_info *csum_info;
 
 			rndis_msg_size += NDIS_CSUM_PPI_SIZE;
-			ppi = init_ppi_data(rndis_msg, NDIS_CSUM_PPI_SIZE,
-					    TCPIP_CHKSUM_PKTINFO);
-
-			csum_info = (struct ndis_tcp_ip_checksum_info *)((void *)ppi +
-									 ppi->ppi_offset);
+			csum_info = init_ppi_data(rndis_msg, NDIS_CSUM_PPI_SIZE,
+						  TCPIP_CHKSUM_PKTINFO);
 
+			csum_info->value = 0;
 			csum_info->transmit.tcp_header_offset = skb_transport_offset(skb);
 
 			if (skb->protocol == htons(ETH_P_IP)) {

@@ -140,6 +140,29 @@ static u32 hv_copyto_ringbuffer(
 	return start_write_offset;
 }
 
+/*
+ *
+ * hv_get_ringbuffer_availbytes()
+ *
+ * Get number of bytes available to read and to write to
+ * for the specified ring buffer
+ */
+static void
+hv_get_ringbuffer_availbytes(const struct hv_ring_buffer_info *rbi,
+			     u32 *read, u32 *write)
+{
+	u32 read_loc, write_loc, dsize;
+
+	/* Capture the read/write indices before they changed */
+	read_loc = READ_ONCE(rbi->ring_buffer->read_index);
+	write_loc = READ_ONCE(rbi->ring_buffer->write_index);
+	dsize = rbi->ring_datasize;
+
+	*write = write_loc >= read_loc ? dsize - (write_loc - read_loc) :
+		read_loc - write_loc;
+	*read = dsize - *write;
+}
+
 /* Get various debug metrics for the specified ring buffer. */
 void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
 				 struct hv_ring_buffer_debug_info *debug_info)

@@ -127,28 +127,6 @@ struct hv_ring_buffer_info {
 	u32 priv_read_index;
 };
 
-/*
- *
- * hv_get_ringbuffer_availbytes()
- *
- * Get number of bytes available to read and to write to
- * for the specified ring buffer
- */
-static inline void
-hv_get_ringbuffer_availbytes(const struct hv_ring_buffer_info *rbi,
-			     u32 *read, u32 *write)
-{
-	u32 read_loc, write_loc, dsize;
-
-	/* Capture the read/write indices before they changed */
-	read_loc = rbi->ring_buffer->read_index;
-	write_loc = rbi->ring_buffer->write_index;
-	dsize = rbi->ring_datasize;
-
-	*write = write_loc >= read_loc ? dsize - (write_loc - read_loc) :
-		read_loc - write_loc;
-	*read = dsize - *write;
-}
 
 static inline u32 hv_get_bytes_to_read(const struct hv_ring_buffer_info *rbi)
 {

@@ -848,7 +848,6 @@ int netvsc_send(struct net_device_context *ndev_ctx,
 	struct hv_netvsc_packet *msd_send = NULL, *cur_send = NULL;
 	struct sk_buff *msd_skb = NULL;
 	bool try_batch;
-	bool xmit_more = (skb != NULL) ? skb->xmit_more : false;
 
 	/* If device is rescinded, return error and packet will get dropped. */
 	if (unlikely(!net_device || net_device->destroy))

@@ -922,7 +921,7 @@ int netvsc_send(struct net_device_context *ndev_ctx,
 		if (msdp->skb)
 			dev_consume_skb_any(msdp->skb);
 
-		if (xmit_more && !packet->cp_partial) {
+		if (skb->xmit_more && !packet->cp_partial) {
 			msdp->skb = skb;
 			msdp->pkt = packet;
 			msdp->count++;