sfc: Only use TX push if a single descriptor is to be written

[pandora-kernel.git] / drivers / net / macvtap.c

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 1b7082d..26106c0 100644 (file)
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -504,10 +504,11 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
                if (copy > size) {
                        ++from;
                        --count;
-               }
+                       offset = 0;
+               } else
+                       offset += size;
                copy -= size;
                offset1 += size;
-               offset = 0;
        }
 
        if (len == offset1)
@@ -517,24 +518,29 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
                struct page *page[MAX_SKB_FRAGS];
                int num_pages;
                unsigned long base;
+               unsigned long truesize;
 
-               len = from->iov_len - offset1;
+               len = from->iov_len - offset;
                if (!len) {
-                       offset1 = 0;
+                       offset = 0;
                        ++from;
                        continue;
                }
-               base = (unsigned long)from->iov_base + offset1;
+               base = (unsigned long)from->iov_base + offset;
                size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
+               if (i + size > MAX_SKB_FRAGS)
+                       return -EMSGSIZE;
                num_pages = get_user_pages_fast(base, size, 0, &page[i]);
-               if ((num_pages != size) ||
-                   (num_pages > MAX_SKB_FRAGS - skb_shinfo(skb)->nr_frags))
-                       /* put_page is in skb free */
+               if (num_pages != size) {
+                       for (i = 0; i < num_pages; i++)
+                               put_page(page[i]);
                        return -EFAULT;
+               }
+               truesize = size * PAGE_SIZE;
                skb->data_len += len;
                skb->len += len;
-               skb->truesize += len;
-               atomic_add(len, &skb->sk->sk_wmem_alloc);
+               skb->truesize += truesize;
+               atomic_add(truesize, &skb->sk->sk_wmem_alloc);
                while (len) {
                        int off = base & ~PAGE_MASK;
                        int size = min_t(int, len, PAGE_SIZE - off);
@@ -545,7 +551,7 @@ static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
                        len -= size;
                        i++;
                }
-               offset1 = 0;
+               offset = 0;
                ++from;
        }
        return 0;
@@ -645,7 +651,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
        int err;
        struct virtio_net_hdr vnet_hdr = { 0 };
        int vnet_hdr_len = 0;
-       int copylen;
+       int copylen = 0;
        bool zerocopy = false;
 
        if (q->flags & IFF_VNET_HDR) {
@@ -674,15 +680,31 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
        if (unlikely(len < ETH_HLEN))
                goto err;
 
+       err = -EMSGSIZE;
+       if (unlikely(count > UIO_MAXIOV))
+               goto err;
+
        if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY))
                zerocopy = true;
 
        if (zerocopy) {
+               /* Userspace may produce vectors with count greater than
+                * MAX_SKB_FRAGS, so we need to linearize parts of the skb
+                * to let the rest of data to be fit in the frags.
+                */
+               if (count > MAX_SKB_FRAGS) {
+                       copylen = iov_length(iv, count - MAX_SKB_FRAGS);
+                       if (copylen < vnet_hdr_len)
+                               copylen = 0;
+                       else
+                               copylen -= vnet_hdr_len;
+               }
                /* There are 256 bytes to be copied in skb, so there is enough
                 * room for skb expand head in case it is used.
                 * The rest buffer is mapped from userspace.
                 */
-               copylen = vnet_hdr.hdr_len;
+               if (copylen < vnet_hdr.hdr_len)
+                       copylen = vnet_hdr.hdr_len;
                if (!copylen)
                        copylen = GOODCOPY_LEN;
        } else
@@ -693,10 +715,9 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
        if (!skb)
                goto err;
 
-       if (zerocopy) {
+       if (zerocopy)
                err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count);
-               skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
-       } else
+       else
                err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len,
                                                   len);
        if (err)
@@ -715,8 +736,10 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
        rcu_read_lock_bh();
        vlan = rcu_dereference_bh(q->vlan);
        /* copy skb_ubuf_info for callback when skb has no error */
-       if (zerocopy)
+       if (zerocopy) {
                skb_shinfo(skb)->destructor_arg = m->msg_control;
+               skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
+       }
        if (vlan)
                macvlan_start_xmit(skb, vlan->dev);
        else