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Commit 562abd39 authored by Paul Durrant's avatar Paul Durrant Committed by David S. Miller
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xen-netback: support multiple extra info fragments passed from frontend 



The code does not currently support a frontend passing multiple extra info
fragments to the backend in a tx request. The xenvif_get_extras() function
handles multiple extra_info fragments but make_tx_response() assumes there
is only ever a single extra info fragment.

This patch modifies xenvif_get_extras() to pass back a count of extra
info fragments, which is then passed to make_tx_response() (after
possibly being stashed in pending_tx_info for deferred responses).

Signed-off-by: default avatarPaul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: default avatarWei Liu <wei.liu2@citrix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6b8abef5

drivers/net/xen-netback/common.h

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ typedef unsigned int pending_ring_idx_t; 


struct pending_tx_info {

	struct xen_netif_tx_request req; /* tx request */

	unsigned int extra_count;

	/* Callback data for released SKBs. The callback is always

	 * xenvif_zerocopy_callback, desc contains the pending_idx, which is

	 * also an index in pending_tx_info array. It is initialized in

drivers/net/xen-netback/netback.c

+42 −23
Original line number Diff line number Diff line
@@ -95,6 +95,7 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, 


static void make_tx_response(struct xenvif_queue *queue,

			     struct xen_netif_tx_request *txp,

			     unsigned int extra_count,

			     s8       st);

static void push_tx_responses(struct xenvif_queue *queue);
@@ -696,14 +697,15 @@ void xenvif_tx_credit_callback(unsigned long data) 
}



static void xenvif_tx_err(struct xenvif_queue *queue,

			  struct xen_netif_tx_request *txp, RING_IDX end)

			  struct xen_netif_tx_request *txp,

			  unsigned int extra_count, RING_IDX end)

{

	RING_IDX cons = queue->tx.req_cons;

	unsigned long flags;



	do {

		spin_lock_irqsave(&queue->response_lock, flags);

		make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);

		make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);

		push_tx_responses(queue);

		spin_unlock_irqrestore(&queue->response_lock, flags);

		if (cons == end)
@@ -724,6 +726,7 @@ static void xenvif_fatal_tx_err(struct xenvif *vif) 


static int xenvif_count_requests(struct xenvif_queue *queue,

				 struct xen_netif_tx_request *first,

				 unsigned int extra_count,

				 struct xen_netif_tx_request *txp,

				 int work_to_do)

{
@@ -812,7 +815,7 @@ static int xenvif_count_requests(struct xenvif_queue *queue, 
	} while (more_data);



	if (drop_err) {

		xenvif_tx_err(queue, first, cons + slots);

		xenvif_tx_err(queue, first, extra_count, cons + slots);

		return drop_err;

	}
@@ -829,6 +832,7 @@ struct xenvif_tx_cb { 
static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,

					   u16 pending_idx,

					   struct xen_netif_tx_request *txp,

					   unsigned int extra_count,

					   struct gnttab_map_grant_ref *mop)

{

	queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
@@ -838,6 +842,7 @@ static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue, 


	memcpy(&queue->pending_tx_info[pending_idx].req, txp,

	       sizeof(*txp));

	queue->pending_tx_info[pending_idx].extra_count = extra_count;

}



static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
@@ -880,7 +885,7 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *que 
	     shinfo->nr_frags++, txp++, gop++) {

		index = pending_index(queue->pending_cons++);

		pending_idx = queue->pending_ring[index];

		xenvif_tx_create_map_op(queue, pending_idx, txp, gop);

		xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);

		frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);

	}
@@ -893,7 +898,8 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *que 
		     shinfo->nr_frags++, txp++, gop++) {

			index = pending_index(queue->pending_cons++);

			pending_idx = queue->pending_ring[index];

			xenvif_tx_create_map_op(queue, pending_idx, txp, gop);

			xenvif_tx_create_map_op(queue, pending_idx, txp, 0,

						gop);

			frag_set_pending_idx(&frags[shinfo->nr_frags],

					     pending_idx);

		}
@@ -1096,6 +1102,7 @@ static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb) 


static int xenvif_get_extras(struct xenvif_queue *queue,

			     struct xen_netif_extra_info *extras,

			     unsigned int *extra_count,

			     int work_to_do)

{

	struct xen_netif_extra_info extra;
@@ -1109,9 +1116,12 @@ static int xenvif_get_extras(struct xenvif_queue *queue, 
		}



		RING_COPY_REQUEST(&queue->tx, cons, &extra);



		queue->tx.req_cons = ++cons;

		(*extra_count)++;



		if (unlikely(!extra.type ||

			     extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {

			queue->tx.req_cons = ++cons;

			netdev_err(queue->vif->dev,

				   "Invalid extra type: %d\n", extra.type);

			xenvif_fatal_tx_err(queue->vif);
@@ -1119,7 +1129,6 @@ static int xenvif_get_extras(struct xenvif_queue *queue, 
		}



		memcpy(&extras[extra.type - 1], &extra, sizeof(extra));

		queue->tx.req_cons = ++cons;

	} while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);



	return work_to_do;
@@ -1294,6 +1303,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, 
		struct xen_netif_tx_request txreq;

		struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];

		struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];

		unsigned int extra_count;

		u16 pending_idx;

		RING_IDX idx;

		int work_to_do;
@@ -1330,8 +1340,10 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, 
		queue->tx.req_cons = ++idx;



		memset(extras, 0, sizeof(extras));

		extra_count = 0;

		if (txreq.flags & XEN_NETTXF_extra_info) {

			work_to_do = xenvif_get_extras(queue, extras,

						       &extra_count,

						       work_to_do);

			idx = queue->tx.req_cons;

			if (unlikely(work_to_do < 0))
@@ -1344,7 +1356,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, 
			extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];

			ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);



			make_tx_response(queue, &txreq,

			make_tx_response(queue, &txreq, extra_count,

					 (ret == 0) ?

					 XEN_NETIF_RSP_OKAY :

					 XEN_NETIF_RSP_ERROR);
@@ -1358,12 +1370,14 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, 
			extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];

			xenvif_mcast_del(queue->vif, extra->u.mcast.addr);



			make_tx_response(queue, &txreq, XEN_NETIF_RSP_OKAY);

			make_tx_response(queue, &txreq, extra_count,

					 XEN_NETIF_RSP_OKAY);

			push_tx_responses(queue);

			continue;

		}



		ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);

		ret = xenvif_count_requests(queue, &txreq, extra_count,

					    txfrags, work_to_do);

		if (unlikely(ret < 0))

			break;
@@ -1372,7 +1386,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, 
		if (unlikely(txreq.size < ETH_HLEN)) {

			netdev_dbg(queue->vif->dev,

				   "Bad packet size: %d\n", txreq.size);

			xenvif_tx_err(queue, &txreq, idx);

			xenvif_tx_err(queue, &txreq, extra_count, idx);

			break;

		}
@@ -1397,7 +1411,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, 
		if (unlikely(skb == NULL)) {

			netdev_dbg(queue->vif->dev,

				   "Can't allocate a skb in start_xmit.\n");

			xenvif_tx_err(queue, &txreq, idx);

			xenvif_tx_err(queue, &txreq, extra_count, idx);

			break;

		}
@@ -1416,7 +1430,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, 
			nskb = xenvif_alloc_skb(0);

			if (unlikely(nskb == NULL)) {

				kfree_skb(skb);

				xenvif_tx_err(queue, &txreq, idx);

				xenvif_tx_err(queue, &txreq, extra_count, idx);

				if (net_ratelimit())

					netdev_err(queue->vif->dev,

						   "Can't allocate the frag_list skb.\n");
@@ -1457,13 +1471,16 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue, 
		if (data_len < txreq.size) {

			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],

					     pending_idx);

			xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop);

			xenvif_tx_create_map_op(queue, pending_idx, &txreq,

						extra_count, gop);

			gop++;

		} else {

			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],

					     INVALID_PENDING_IDX);

			memcpy(&queue->pending_tx_info[pending_idx].req, &txreq,

			       sizeof(txreq));

			memcpy(&queue->pending_tx_info[pending_idx].req,

			       &txreq, sizeof(txreq));

			queue->pending_tx_info[pending_idx].extra_count =

				extra_count;

		}



		queue->pending_cons++;
@@ -1804,7 +1821,8 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, 


	spin_lock_irqsave(&queue->response_lock, flags);



	make_tx_response(queue, &pending_tx_info->req, status);

	make_tx_response(queue, &pending_tx_info->req,

			 pending_tx_info->extra_count, status);



	/* Release the pending index before pusing the Tx response so

	 * its available before a new Tx request is pushed by the
@@ -1821,6 +1839,7 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, 


static void make_tx_response(struct xenvif_queue *queue,

			     struct xen_netif_tx_request *txp,

			     unsigned int extra_count,

			     s8       st)

{

	RING_IDX i = queue->tx.rsp_prod_pvt;
@@ -1830,7 +1849,7 @@ static void make_tx_response(struct xenvif_queue *queue, 
	resp->id     = txp->id;

	resp->status = st;



	if (txp->flags & XEN_NETTXF_extra_info)

	while (extra_count-- != 0)

		RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;



	queue->tx.rsp_prod_pvt = ++i;