Commit a55e8bb8 authored by David Vrabel's avatar David Vrabel Committed by David S. Miller
Browse files

xen-netfront: refactor making Tx requests 



Eliminate all the duplicate code for making Tx requests by
consolidating them into a single xennet_make_one_txreq() function.

xennet_make_one_txreq() and xennet_make_txreqs() work with pages and
offsets so it will be easier to make netfront handle highmem frags in
the future.

Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e84448d5

drivers/net/xen-netfront.c

+67 −114
Original line number Diff line number Diff line
@@ -421,99 +421,56 @@ static void xennet_tx_buf_gc(struct netfront_queue *queue) 
	xennet_maybe_wake_tx(queue);

}



static void xennet_make_frags(struct sk_buff *skb, struct netfront_queue *queue,

			      struct xen_netif_tx_request *tx)

{

	char *data = skb->data;

	unsigned long mfn;

	RING_IDX prod = queue->tx.req_prod_pvt;

	int frags = skb_shinfo(skb)->nr_frags;

	unsigned int offset = offset_in_page(data);

	unsigned int len = skb_headlen(skb);

static struct xen_netif_tx_request *xennet_make_one_txreq(

	struct netfront_queue *queue, struct sk_buff *skb,

	struct page *page, unsigned int offset, unsigned int len)

{

	unsigned int id;

	struct xen_netif_tx_request *tx;

	grant_ref_t ref;

	int i;



	/* While the header overlaps a page boundary (including being

	   larger than a page), split it it into page-sized chunks. */

	while (len > PAGE_SIZE - offset) {

		tx->size = PAGE_SIZE - offset;

		tx->flags |= XEN_NETTXF_more_data;

		len -= tx->size;

		data += tx->size;

		offset = 0;

	len = min_t(unsigned int, PAGE_SIZE - offset, len);



	id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);

		queue->tx_skbs[id].skb = skb_get(skb);

		tx = RING_GET_REQUEST(&queue->tx, prod++);

		tx->id = id;

	tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);

	ref = gnttab_claim_grant_reference(&queue->gref_tx_head);

	BUG_ON((signed short)ref < 0);



		mfn = virt_to_mfn(data);

	gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,

						mfn, GNTMAP_readonly);

					page_to_mfn(page), GNTMAP_readonly);



		queue->grant_tx_page[id] = virt_to_page(data);

		tx->gref = queue->grant_tx_ref[id] = ref;

	queue->tx_skbs[id].skb = skb;

	queue->grant_tx_page[id] = page;

	queue->grant_tx_ref[id] = ref;



	tx->id = id;

	tx->gref = ref;

	tx->offset = offset;

	tx->size = len;

	tx->flags = 0;

	}



	/* Grant backend access to each skb fragment page. */

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

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

		struct page *page = skb_frag_page(frag);



		len = skb_frag_size(frag);

		offset = frag->page_offset;

	return tx;

}



static struct xen_netif_tx_request *xennet_make_txreqs(

	struct netfront_queue *queue, struct xen_netif_tx_request *tx,

	struct sk_buff *skb, struct page *page,

	unsigned int offset, unsigned int len)

{

	/* Skip unused frames from start of page */

	page += offset >> PAGE_SHIFT;

	offset &= ~PAGE_MASK;



		while (len > 0) {

			unsigned long bytes;



			bytes = PAGE_SIZE - offset;

			if (bytes > len)

				bytes = len;



	while (len) {

		tx->flags |= XEN_NETTXF_more_data;



			id = get_id_from_freelist(&queue->tx_skb_freelist,

						  queue->tx_skbs);

			queue->tx_skbs[id].skb = skb_get(skb);

			tx = RING_GET_REQUEST(&queue->tx, prod++);

			tx->id = id;

			ref = gnttab_claim_grant_reference(&queue->gref_tx_head);

			BUG_ON((signed short)ref < 0);



			mfn = pfn_to_mfn(page_to_pfn(page));

			gnttab_grant_foreign_access_ref(ref,

							queue->info->xbdev->otherend_id,

							mfn, GNTMAP_readonly);



			queue->grant_tx_page[id] = page;

			tx->gref = queue->grant_tx_ref[id] = ref;

			tx->offset = offset;

			tx->size = bytes;

			tx->flags = 0;



			offset += bytes;

			len -= bytes;



			/* Next frame */

			if (offset == PAGE_SIZE && len) {

				BUG_ON(!PageCompound(page));

		tx = xennet_make_one_txreq(queue, skb_get(skb),

					   page, offset, len);

		page++;

		offset = 0;

			}

		}

		len -= tx->size;

	}



	queue->tx.req_prod_pvt = prod;

	return tx;

}



/*
@@ -561,18 +518,15 @@ static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb, 


static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)

{

	unsigned short id;

	struct netfront_info *np = netdev_priv(dev);

	struct netfront_stats *stats = this_cpu_ptr(np->stats);

	struct xen_netif_tx_request *tx;

	char *data = skb->data;

	RING_IDX i;

	grant_ref_t ref;

	unsigned long mfn;

	struct xen_netif_tx_request *tx, *first_tx;

	unsigned int i;

	int notify;

	int slots;

	unsigned int offset = offset_in_page(data);

	unsigned int len = skb_headlen(skb);

	struct page *page;

	unsigned int offset;

	unsigned int len;

	unsigned long flags;

	struct netfront_queue *queue = NULL;

	unsigned int num_queues = dev->real_num_tx_queues;
@@ -601,11 +555,12 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
				    slots, skb->len);

		if (skb_linearize(skb))

			goto drop;

		data = skb->data;

		offset = offset_in_page(data);

		len = skb_headlen(skb);

	}



	page = virt_to_page(skb->data);

	offset = offset_in_page(skb->data);

	len = skb_headlen(skb);



	spin_lock_irqsave(&queue->tx_lock, flags);



	if (unlikely(!netif_carrier_ok(dev) ||
@@ -615,25 +570,13 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		goto drop;

	}



	i = queue->tx.req_prod_pvt;



	id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);

	queue->tx_skbs[id].skb = skb;



	tx = RING_GET_REQUEST(&queue->tx, i);



	tx->id   = id;

	ref = gnttab_claim_grant_reference(&queue->gref_tx_head);

	BUG_ON((signed short)ref < 0);

	mfn = virt_to_mfn(data);

	gnttab_grant_foreign_access_ref(

		ref, queue->info->xbdev->otherend_id, mfn, GNTMAP_readonly);

	queue->grant_tx_page[id] = virt_to_page(data);

	tx->gref = queue->grant_tx_ref[id] = ref;

	tx->offset = offset;

	tx->size = len;

	/* First request for the linear area. */

	first_tx = tx = xennet_make_one_txreq(queue, skb,

					      page, offset, len);

	page++;

	offset = 0;

	len -= tx->size;



	tx->flags = 0;

	if (skb->ip_summed == CHECKSUM_PARTIAL)

		/* local packet? */

		tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
@@ -641,11 +584,12 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		/* remote but checksummed. */

		tx->flags |= XEN_NETTXF_data_validated;



	/* Optional extra info after the first request. */

	if (skb_shinfo(skb)->gso_size) {

		struct xen_netif_extra_info *gso;



		gso = (struct xen_netif_extra_info *)

			RING_GET_REQUEST(&queue->tx, ++i);

			RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);



		tx->flags |= XEN_NETTXF_extra_info;
@@ -660,10 +604,19 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		gso->flags = 0;

	}



	queue->tx.req_prod_pvt = i + 1;

	/* Requests for the rest of the linear area. */

	tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);



	/* Requests for all the frags. */

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

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

		tx = xennet_make_txreqs(queue, tx, skb,

					skb_frag_page(frag), frag->page_offset,

					skb_frag_size(frag));

	}



	xennet_make_frags(skb, queue, tx);

	tx->size = skb->len;

	/* First request has the packet length. */

	first_tx->size = skb->len;



	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);

	if (notify)

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