Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[linux-2.6-block.git] / drivers / net / xen-netback / netback.c

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 77127ca08ca42040c71b31c81106bf74e7bf6b5a..769e553d3f45dfc56a12caf39133dd9870fcb69c 100644 (file)
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1030,14 +1030,21 @@ static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 {
        struct gnttab_map_grant_ref *gop_map = *gopp_map;
        u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
+       /* This always points to the shinfo of the skb being checked, which
+        * could be either the first or the one on the frag_list
+        */
        struct skb_shared_info *shinfo = skb_shinfo(skb);
+       /* If this is non-NULL, we are currently checking the frag_list skb, and
+        * this points to the shinfo of the first one
+        */
+       struct skb_shared_info *first_shinfo = NULL;
        int nr_frags = shinfo->nr_frags;
+       const bool sharedslot = nr_frags &&
+                               frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
        int i, err;
-       struct sk_buff *first_skb = NULL;
 
        /* Check status of header. */
        err = (*gopp_copy)->status;
-       (*gopp_copy)++;
        if (unlikely(err)) {
                if (net_ratelimit())
                        netdev_dbg(queue->vif->dev,
@@ -1045,8 +1052,12 @@ static int xenvif_tx_check_gop(struct xenvif_queue *queue,
                                   (*gopp_copy)->status,
                                   pending_idx,
                                   (*gopp_copy)->source.u.ref);
-               xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
+               /* The first frag might still have this slot mapped */
+               if (!sharedslot)
+                       xenvif_idx_release(queue, pending_idx,
+                                          XEN_NETIF_RSP_ERROR);
        }
+       (*gopp_copy)++;
 
 check_frags:
        for (i = 0; i < nr_frags; i++, gop_map++) {
@@ -1062,8 +1073,19 @@ check_frags:
                                                pending_idx,
                                                gop_map->handle);
                        /* Had a previous error? Invalidate this fragment. */
-                       if (unlikely(err))
+                       if (unlikely(err)) {
                                xenvif_idx_unmap(queue, pending_idx);
+                               /* If the mapping of the first frag was OK, but
+                                * the header's copy failed, and they are
+                                * sharing a slot, send an error
+                                */
+                               if (i == 0 && sharedslot)
+                                       xenvif_idx_release(queue, pending_idx,
+                                                          XEN_NETIF_RSP_ERROR);
+                               else
+                                       xenvif_idx_release(queue, pending_idx,
+                                                          XEN_NETIF_RSP_OKAY);
+                       }
                        continue;
                }
 
@@ -1075,42 +1097,53 @@ check_frags:
                                   gop_map->status,
                                   pending_idx,
                                   gop_map->ref);
+
                xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
 
                /* Not the first error? Preceding frags already invalidated. */
                if (err)
                        continue;
-               /* First error: invalidate preceding fragments. */
+
+               /* First error: if the header haven't shared a slot with the
+                * first frag, release it as well.
+                */
+               if (!sharedslot)
+                       xenvif_idx_release(queue,
+                                          XENVIF_TX_CB(skb)->pending_idx,
+                                          XEN_NETIF_RSP_OKAY);
+
+               /* Invalidate preceding fragments of this skb. */
                for (j = 0; j < i; j++) {
                        pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
                        xenvif_idx_unmap(queue, pending_idx);
+                       xenvif_idx_release(queue, pending_idx,
+                                          XEN_NETIF_RSP_OKAY);
+               }
+
+               /* And if we found the error while checking the frag_list, unmap
+                * the first skb's frags
+                */
+               if (first_shinfo) {
+                       for (j = 0; j < first_shinfo->nr_frags; j++) {
+                               pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
+                               xenvif_idx_unmap(queue, pending_idx);
+                               xenvif_idx_release(queue, pending_idx,
+                                                  XEN_NETIF_RSP_OKAY);
+                       }
                }
 
                /* Remember the error: invalidate all subsequent fragments. */
                err = newerr;
        }
 
-       if (skb_has_frag_list(skb)) {
-               first_skb = skb;
-               skb = shinfo->frag_list;
-               shinfo = skb_shinfo(skb);
+       if (skb_has_frag_list(skb) && !first_shinfo) {
+               first_shinfo = skb_shinfo(skb);
+               shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
                nr_frags = shinfo->nr_frags;
 
                goto check_frags;
        }
 
-       /* There was a mapping error in the frag_list skb. We have to unmap
-        * the first skb's frags
-        */
-       if (first_skb && err) {
-               int j;
-               shinfo = skb_shinfo(first_skb);
-               for (j = 0; j < shinfo->nr_frags; j++) {
-                       pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
-                       xenvif_idx_unmap(queue, pending_idx);
-               }
-       }
-
        *gopp_map = gop_map;
        return err;
 }
@@ -1518,7 +1551,16 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 
                /* Check the remap error code. */
                if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
+                       /* If there was an error, xenvif_tx_check_gop is
+                        * expected to release all the frags which were mapped,
+                        * so kfree_skb shouldn't do it again
+                        */
                        skb_shinfo(skb)->nr_frags = 0;
+                       if (skb_has_frag_list(skb)) {
+                               struct sk_buff *nskb =
+                                               skb_shinfo(skb)->frag_list;
+                               skb_shinfo(nskb)->nr_frags = 0;
+                       }
                        kfree_skb(skb);
                        continue;
                }
@@ -1822,8 +1864,6 @@ void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
                           tx_unmap_op.status);
                BUG();
        }
-
-       xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_OKAY);
 }
 
 static inline int rx_work_todo(struct xenvif_queue *queue)