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: Paul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 112825200d4192d6da01ae5b70ba52e41c886ffc..f44b388464208d25b4d11613a2f8b16862256ec4 100644 (file)
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -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

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 61b97c34bb3b86412b06578f97a15a596df9965e..b42f26029225fd69d9c57fe3088b31fdb5ab39bb 100644 (file)
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -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;
        }
 
@@ -827,9 +830,10 @@ struct xenvif_tx_cb {
 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 
 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
-                                         u16 pending_idx,
-                                         struct xen_netif_tx_request *txp,
-                                         struct gnttab_map_grant_ref *mop)
+                                          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];
        gnttab_set_map_op(mop, idx_to_kaddr(queue, 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);
                }
@@ -1095,8 +1101,9 @@ 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,
-                               int work_to_do)
+                            struct xen_netif_extra_info *extras,
+                            unsigned int *extra_count,
+                            int work_to_do)
 {
        struct xen_netif_extra_info extra;
        RING_IDX cons = queue->tx.req_cons;
@@ -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;