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path: root/drivers/net/tun.c
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Diffstat (limited to 'drivers/net/tun.c')
-rw-r--r--drivers/net/tun.c66
1 files changed, 62 insertions, 4 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 95931a5a988..6daea0c9186 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -358,6 +358,66 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
return mask;
}
+/* prepad is the amount to reserve at front. len is length after that.
+ * linear is a hint as to how much to copy (usually headers). */
+static struct sk_buff *tun_alloc_skb(size_t prepad, size_t len, size_t linear,
+ gfp_t gfp)
+{
+ struct sk_buff *skb;
+ unsigned int i;
+
+ skb = alloc_skb(prepad + len, gfp|__GFP_NOWARN);
+ if (skb) {
+ skb_reserve(skb, prepad);
+ skb_put(skb, len);
+ return skb;
+ }
+
+ /* Under a page? Don't bother with paged skb. */
+ if (prepad + len < PAGE_SIZE)
+ return NULL;
+
+ /* Start with a normal skb, and add pages. */
+ skb = alloc_skb(prepad + linear, gfp);
+ if (!skb)
+ return NULL;
+
+ skb_reserve(skb, prepad);
+ skb_put(skb, linear);
+
+ len -= linear;
+
+ for (i = 0; i < MAX_SKB_FRAGS; i++) {
+ skb_frag_t *f = &skb_shinfo(skb)->frags[i];
+
+ f->page = alloc_page(gfp|__GFP_ZERO);
+ if (!f->page)
+ break;
+
+ f->page_offset = 0;
+ f->size = PAGE_SIZE;
+
+ skb->data_len += PAGE_SIZE;
+ skb->len += PAGE_SIZE;
+ skb->truesize += PAGE_SIZE;
+ skb_shinfo(skb)->nr_frags++;
+
+ if (len < PAGE_SIZE) {
+ len = 0;
+ break;
+ }
+ len -= PAGE_SIZE;
+ }
+
+ /* Too large, or alloc fail? */
+ if (unlikely(len)) {
+ kfree_skb(skb);
+ skb = NULL;
+ }
+
+ return skb;
+}
+
/* Get packet from user space buffer */
static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
{
@@ -391,14 +451,12 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv,
return -EINVAL;
}
- if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
+ if (!(skb = tun_alloc_skb(align, len, gso.hdr_len, GFP_KERNEL))) {
tun->dev->stats.rx_dropped++;
return -ENOMEM;
}
- if (align)
- skb_reserve(skb, align);
- if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
+ if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
tun->dev->stats.rx_dropped++;
kfree_skb(skb);
return -EFAULT;