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Commit 54a7357f authored by KY Srinivasan's avatar KY Srinivasan Committed by David S. Miller
Browse files

Drivers: net: hyperv: Enable scatter gather I/O 



Cleanup the code and enable scatter gather I/O.

Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: default avatarHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3ee2f8ce

drivers/net/hyperv/netvsc_drv.c

+114 −39
Original line number Diff line number Diff line
@@ -140,21 +140,123 @@ static void netvsc_xmit_completion(void *context) 
		dev_kfree_skb_any(skb);

}



static u32 fill_pg_buf(struct page *page, u32 offset, u32 len,

			struct hv_page_buffer *pb)

{

	int j = 0;



	/* Deal with compund pages by ignoring unused part

	 * of the page.

	 */

	page += (offset >> PAGE_SHIFT);

	offset &= ~PAGE_MASK;



	while (len > 0) {

		unsigned long bytes;



		bytes = PAGE_SIZE - offset;

		if (bytes > len)

			bytes = len;

		pb[j].pfn = page_to_pfn(page);

		pb[j].offset = offset;

		pb[j].len = bytes;



		offset += bytes;

		len -= bytes;



		if (offset == PAGE_SIZE && len) {

			page++;

			offset = 0;

			j++;

		}

	}



	return j + 1;

}



static void init_page_array(void *hdr, u32 len, struct sk_buff *skb,

			    struct hv_page_buffer *pb)

{

	u32 slots_used = 0;

	char *data = skb->data;

	int frags = skb_shinfo(skb)->nr_frags;

	int i;



	/* The packet is laid out thus:

	 * 1. hdr

	 * 2. skb linear data

	 * 3. skb fragment data

	 */

	if (hdr != NULL)

		slots_used += fill_pg_buf(virt_to_page(hdr),

					offset_in_page(hdr),

					len, &pb[slots_used]);



	slots_used += fill_pg_buf(virt_to_page(data),

				offset_in_page(data),

				skb_headlen(skb), &pb[slots_used]);



	for (i = 0; i < frags; i++) {

		skb_frag_t *frag = skb_shinfo(skb)->frags + i;



		slots_used += fill_pg_buf(skb_frag_page(frag),

					frag->page_offset,

					skb_frag_size(frag), &pb[slots_used]);

	}

}



static int count_skb_frag_slots(struct sk_buff *skb)

{

	int i, frags = skb_shinfo(skb)->nr_frags;

	int pages = 0;



	for (i = 0; i < frags; i++) {

		skb_frag_t *frag = skb_shinfo(skb)->frags + i;

		unsigned long size = skb_frag_size(frag);

		unsigned long offset = frag->page_offset;



		/* Skip unused frames from start of page */

		offset &= ~PAGE_MASK;

		pages += PFN_UP(offset + size);

	}

	return pages;

}



static int netvsc_get_slots(struct sk_buff *skb)

{

	char *data = skb->data;

	unsigned int offset = offset_in_page(data);

	unsigned int len = skb_headlen(skb);

	int slots;

	int frag_slots;



	slots = DIV_ROUND_UP(offset + len, PAGE_SIZE);

	frag_slots = count_skb_frag_slots(skb);

	return slots + frag_slots;

}



static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)

{

	struct net_device_context *net_device_ctx = netdev_priv(net);

	struct hv_netvsc_packet *packet;

	int ret;

	unsigned int i, num_pages, npg_data;

	unsigned int num_data_pages;



	/* Add multipages for skb->data and additional 2 for RNDIS */

	npg_data = (((unsigned long)skb->data + skb_headlen(skb) - 1)

		>> PAGE_SHIFT) - ((unsigned long)skb->data >> PAGE_SHIFT) + 1;

	num_pages = skb_shinfo(skb)->nr_frags + npg_data + 2;

	/* We will atmost need two pages to describe the rndis

	 * header. We can only transmit MAX_PAGE_BUFFER_COUNT number

	 * of pages in a single packet.

	 */

	num_data_pages = netvsc_get_slots(skb) + 2;

	if (num_data_pages > MAX_PAGE_BUFFER_COUNT) {

		netdev_err(net, "Packet too big: %u\n", skb->len);

		dev_kfree_skb(skb);

		net->stats.tx_dropped++;

		return NETDEV_TX_OK;

	}



	/* Allocate a netvsc packet based on # of frags. */

	packet = kzalloc(sizeof(struct hv_netvsc_packet) +

			 (num_pages * sizeof(struct hv_page_buffer)) +

			 (num_data_pages * sizeof(struct hv_page_buffer)) +

			 sizeof(struct rndis_message) +

			 NDIS_VLAN_PPI_SIZE, GFP_ATOMIC);

	if (!packet) {
@@ -170,43 +272,16 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net) 


	packet->extension = (void *)(unsigned long)packet +

			sizeof(struct hv_netvsc_packet) +

				    (num_pages * sizeof(struct hv_page_buffer));

			(num_data_pages * sizeof(struct hv_page_buffer));



	/* If the rndis msg goes beyond 1 page, we will add 1 later */

	packet->page_buf_cnt = num_pages - 1;

	packet->page_buf_cnt = num_data_pages - 1;



	/* Initialize it from the skb */

	packet->total_data_buflen = skb->len;



	/* Start filling in the page buffers starting after RNDIS buffer. */

	packet->page_buf[1].pfn = virt_to_phys(skb->data) >> PAGE_SHIFT;

	packet->page_buf[1].offset

		= (unsigned long)skb->data & (PAGE_SIZE - 1);

	if (npg_data == 1)

		packet->page_buf[1].len = skb_headlen(skb);

	else

		packet->page_buf[1].len = PAGE_SIZE

			- packet->page_buf[1].offset;



	for (i = 2; i <= npg_data; i++) {

		packet->page_buf[i].pfn = virt_to_phys(skb->data

			+ PAGE_SIZE * (i-1)) >> PAGE_SHIFT;

		packet->page_buf[i].offset = 0;

		packet->page_buf[i].len = PAGE_SIZE;

	}

	if (npg_data > 1)

		packet->page_buf[npg_data].len = (((unsigned long)skb->data

			+ skb_headlen(skb) - 1) & (PAGE_SIZE - 1)) + 1;



	/* Additional fragments are after SKB data */

	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {

		const skb_frag_t *f = &skb_shinfo(skb)->frags[i];



		packet->page_buf[i+npg_data+1].pfn =

			page_to_pfn(skb_frag_page(f));

		packet->page_buf[i+npg_data+1].offset = f->page_offset;

		packet->page_buf[i+npg_data+1].len = skb_frag_size(f);

	}

	init_page_array(NULL, 0, skb, &packet->page_buf[1]);



	/* Set the completion routine */

	packet->completion.send.send_completion = netvsc_xmit_completion;
@@ -451,8 +526,8 @@ static int netvsc_probe(struct hv_device *dev, 
	net->netdev_ops = &device_ops;



	/* TODO: Add GSO and Checksum offload */

	net->hw_features = 0;

	net->features = NETIF_F_HW_VLAN_CTAG_TX;

	net->hw_features = NETIF_F_SG;

	net->features = NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_SG;



	SET_ETHTOOL_OPS(net, &ethtool_ops);

	SET_NETDEV_DEV(net, &dev->device);