1 files changed, 114 insertions, 39 deletions

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 9ef6be90a81c..1f7b12f9e6fb 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -140,21 +140,123 @@ static void netvsc_xmit_completion(void *context)
                 dev_kfree_skb_any(skb);
 }
 
+static u32 fill_pg_buf(struct page *page, u32 offset, u32 len,
+                        struct hv_page_buffer *pb)
+{
+        int j = 0;
+
+        /* Deal with compund pages by ignoring unused part
+         * of the page.
+         */
+        page += (offset >> PAGE_SHIFT);
+        offset &= ~PAGE_MASK;
+
+        while (len > 0) {
+                unsigned long bytes;
+
+                bytes = PAGE_SIZE - offset;
+                if (bytes > len)
+                        bytes = len;
+                pb[j].pfn = page_to_pfn(page);
+                pb[j].offset = offset;
+                pb[j].len = bytes;
+
+                offset += bytes;
+                len -= bytes;
+
+                if (offset == PAGE_SIZE && len) {
+                        page++;
+                        offset = 0;
+                        j++;
+                }
+        }
+
+        return j + 1;
+}
+
+static void init_page_array(void *hdr, u32 len, struct sk_buff *skb,
+                            struct hv_page_buffer *pb)
+{
+        u32 slots_used = 0;
+        char *data = skb->data;
+        int frags = skb_shinfo(skb)->nr_frags;
+        int i;
+
+        /* The packet is laid out thus:
+         * 1. hdr
+         * 2. skb linear data
+         * 3. skb fragment data
+         */
+        if (hdr != NULL)
+                slots_used += fill_pg_buf(virt_to_page(hdr),
+                                        offset_in_page(hdr),
+                                        len, &pb[slots_used]);
+
+        slots_used += fill_pg_buf(virt_to_page(data),
+                                offset_in_page(data),
+                                skb_headlen(skb), &pb[slots_used]);
+
+        for (i = 0; i < frags; i++) {
+                skb_frag_t *frag = skb_shinfo(skb)->frags + i;
+
+                slots_used += fill_pg_buf(skb_frag_page(frag),
+                                        frag->page_offset,
+                                        skb_frag_size(frag), &pb[slots_used]);
+        }
+}
+
+static int 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 netvsc_get_slots(struct sk_buff *skb)
+{
+        char *data = skb->data;
+        unsigned int offset = offset_in_page(data);
+        unsigned int len = skb_headlen(skb);
+        int slots;
+        int frag_slots;
+
+        slots = DIV_ROUND_UP(offset + len, PAGE_SIZE);
+        frag_slots = count_skb_frag_slots(skb);
+        return slots + frag_slots;
+}
+
 static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 {
         struct net_device_context *net_device_ctx = netdev_priv(net);
         struct hv_netvsc_packet *packet;
         int ret;
-        unsigned int i, num_pages, npg_data;
+        unsigned int num_data_pages;
 
-        /* Add multipages for skb->data and additional 2 for RNDIS */
-        npg_data = (((unsigned long)skb->data + skb_headlen(skb) - 1)
-                >> PAGE_SHIFT) - ((unsigned long)skb->data >> PAGE_SHIFT) + 1;
-        num_pages = skb_shinfo(skb)->nr_frags + npg_data + 2;
+        /* We will atmost need two pages to describe the rndis
+         * header. We can only transmit MAX_PAGE_BUFFER_COUNT number
+         * of pages in a single packet.
+         */
+        num_data_pages = netvsc_get_slots(skb) + 2;
+        if (num_data_pages > MAX_PAGE_BUFFER_COUNT) {
+                netdev_err(net, "Packet too big: %u\n", skb->len);
+                dev_kfree_skb(skb);
+                net->stats.tx_dropped++;
+                return NETDEV_TX_OK;
+        }
 
         /* Allocate a netvsc packet based on # of frags. */
         packet = kzalloc(sizeof(struct hv_netvsc_packet) +
-                         (num_pages * sizeof(struct hv_page_buffer)) +
+                         (num_data_pages * sizeof(struct hv_page_buffer)) +
                          sizeof(struct rndis_message) +
                          NDIS_VLAN_PPI_SIZE, GFP_ATOMIC);
         if (!packet) {
@@ -169,44 +271,17 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
         packet->vlan_tci = skb->vlan_tci;
 
         packet->extension = (void *)(unsigned long)packet +
-                                sizeof(struct hv_netvsc_packet) +
-                                    (num_pages * sizeof(struct hv_page_buffer));
+                        sizeof(struct hv_netvsc_packet) +
+                        (num_data_pages * sizeof(struct hv_page_buffer));
 
         /* If the rndis msg goes beyond 1 page, we will add 1 later */
-        packet->page_buf_cnt = num_pages - 1;
+        packet->page_buf_cnt = num_data_pages - 1;
 
         /* Initialize it from the skb */
         packet->total_data_buflen = skb->len;
 
         /* Start filling in the page buffers starting after RNDIS buffer. */
-        packet->page_buf[1].pfn = virt_to_phys(skb->data) >> PAGE_SHIFT;
-        packet->page_buf[1].offset
-                = (unsigned long)skb->data & (PAGE_SIZE - 1);
-        if (npg_data == 1)
-                packet->page_buf[1].len = skb_headlen(skb);
-        else
-                packet->page_buf[1].len = PAGE_SIZE
-                        - packet->page_buf[1].offset;
-
-        for (i = 2; i <= npg_data; i++) {
-                packet->page_buf[i].pfn = virt_to_phys(skb->data
-                        + PAGE_SIZE * (i-1)) >> PAGE_SHIFT;
-                packet->page_buf[i].offset = 0;
-                packet->page_buf[i].len = PAGE_SIZE;
-        }
-        if (npg_data > 1)
-                packet->page_buf[npg_data].len = (((unsigned long)skb->data
-                        + skb_headlen(skb) - 1) & (PAGE_SIZE - 1)) + 1;
-
-        /* Additional fragments are after SKB data */
-        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
-                const skb_frag_t *f = &skb_shinfo(skb)->frags[i];
-
-                packet->page_buf[i+npg_data+1].pfn =
-                        page_to_pfn(skb_frag_page(f));
-                packet->page_buf[i+npg_data+1].offset = f->page_offset;
-                packet->page_buf[i+npg_data+1].len = skb_frag_size(f);
-        }
+        init_page_array(NULL, 0, skb, &packet->page_buf[1]);
 
         /* Set the completion routine */
         packet->completion.send.send_completion = netvsc_xmit_completion;
@@ -451,8 +526,8 @@ static int netvsc_probe(struct hv_device *dev,
         net->netdev_ops = &device_ops;
 
         /* TODO: Add GSO and Checksum offload */
-        net->hw_features = 0;
-        net->features = NETIF_F_HW_VLAN_CTAG_TX;
+        net->hw_features = NETIF_F_SG;
+        net->features = NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_SG;
 
         SET_ETHTOOL_OPS(net, &ethtool_ops);
         SET_NETDEV_DEV(net, &dev->device);