Merge tag 'for-v3.8-part2' of git://git.infradead.org/battery-2.6

[firefly-linux-kernel-4.4.55.git] / drivers / net / xen-netfront.c

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index caa011008cd0c9fe11b38507e7f550552bd93170..c26e28b4bd9f985a4d7c6d3307d969bb671bf6f7 100644 (file)
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -452,29 +452,85 @@ static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
        /* 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);
 
-               tx->flags |= XEN_NETTXF_more_data;
+               len = skb_frag_size(frag);
+               offset = frag->page_offset;
 
-               id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
-               np->tx_skbs[id].skb = skb_get(skb);
-               tx = RING_GET_REQUEST(&np->tx, prod++);
-               tx->id = id;
-               ref = gnttab_claim_grant_reference(&np->gref_tx_head);
-               BUG_ON((signed short)ref < 0);
+               /* Data must not cross a page boundary. */
+               BUG_ON(len + offset > PAGE_SIZE<<compound_order(page));
 
-               mfn = pfn_to_mfn(page_to_pfn(skb_frag_page(frag)));
-               gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
-                                               mfn, GNTMAP_readonly);
+               /* Skip unused frames from start of page */
+               page += offset >> PAGE_SHIFT;
+               offset &= ~PAGE_MASK;
 
-               tx->gref = np->grant_tx_ref[id] = ref;
-               tx->offset = frag->page_offset;
-               tx->size = skb_frag_size(frag);
-               tx->flags = 0;
+               while (len > 0) {
+                       unsigned long bytes;
+
+                       BUG_ON(offset >= PAGE_SIZE);
+
+                       bytes = PAGE_SIZE - offset;
+                       if (bytes > len)
+                               bytes = len;
+
+                       tx->flags |= XEN_NETTXF_more_data;
+
+                       id = get_id_from_freelist(&np->tx_skb_freelist,
+                                                 np->tx_skbs);
+                       np->tx_skbs[id].skb = skb_get(skb);
+                       tx = RING_GET_REQUEST(&np->tx, prod++);
+                       tx->id = id;
+                       ref = gnttab_claim_grant_reference(&np->gref_tx_head);
+                       BUG_ON((signed short)ref < 0);
+
+                       mfn = pfn_to_mfn(page_to_pfn(page));
+                       gnttab_grant_foreign_access_ref(ref,
+                                                       np->xbdev->otherend_id,
+                                                       mfn, GNTMAP_readonly);
+
+                       tx->gref = np->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));
+                               page++;
+                               offset = 0;
+                       }
+               }
        }
 
        np->tx.req_prod_pvt = prod;
 }
 
+/*
+ * Count how many ring slots are required to send the frags of this
+ * skb. Each frag might be a compound page.
+ */
+static int xennet_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 xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        unsigned short id;
@@ -487,23 +543,23 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
        grant_ref_t ref;
        unsigned long mfn;
        int notify;
-       int frags = skb_shinfo(skb)->nr_frags;
+       int slots;
        unsigned int offset = offset_in_page(data);
        unsigned int len = skb_headlen(skb);
        unsigned long flags;
 
-       frags += DIV_ROUND_UP(offset + len, PAGE_SIZE);
-       if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
-               printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
-                      frags);
-               dump_stack();
+       slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) +
+               xennet_count_skb_frag_slots(skb);
+       if (unlikely(slots > MAX_SKB_FRAGS + 1)) {
+               net_alert_ratelimited(
+                       "xennet: skb rides the rocket: %d slots\n", slots);
                goto drop;
        }
 
        spin_lock_irqsave(&np->tx_lock, flags);
 
        if (unlikely(!netif_carrier_ok(dev) ||
-                    (frags > 1 && !xennet_can_sg(dev)) ||
+                    (slots > 1 && !xennet_can_sg(dev)) ||
                     netif_needs_gso(skb, netif_skb_features(skb)))) {
                spin_unlock_irqrestore(&np->tx_lock, flags);
                goto drop;
@@ -1255,7 +1311,7 @@ static const struct net_device_ops xennet_netdev_ops = {
 #endif
 };
 
-static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev)
+static struct net_device *xennet_create_dev(struct xenbus_device *dev)
 {
        int i, err;
        struct net_device *netdev;
@@ -1351,8 +1407,8 @@ static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev
  * structures and the ring buffers for communication with the backend, and
  * inform the backend of the appropriate details for those.
  */
-static int __devinit netfront_probe(struct xenbus_device *dev,
-                                   const struct xenbus_device_id *id)
+static int netfront_probe(struct xenbus_device *dev,
+                         const struct xenbus_device_id *id)
 {
        int err;
        struct net_device *netdev;
@@ -1911,7 +1967,7 @@ static const struct xenbus_device_id netfront_ids[] = {
 };
 
 
-static int __devexit xennet_remove(struct xenbus_device *dev)
+static int xennet_remove(struct xenbus_device *dev)
 {
        struct netfront_info *info = dev_get_drvdata(&dev->dev);
 
@@ -1934,7 +1990,7 @@ static int __devexit xennet_remove(struct xenbus_device *dev)
 
 static DEFINE_XENBUS_DRIVER(netfront, ,
        .probe = netfront_probe,
-       .remove = __devexit_p(xennet_remove),
+       .remove = xennet_remove,
        .resume = netfront_resume,
        .otherend_changed = netback_changed,
 );