+static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
+ char __user *from, char *to,
+ int copy, int offset)
+{
+ if (skb->ip_summed == CHECKSUM_NONE) {
+ int err = 0;
+ __wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err);
+ if (err)
+ return err;
+ skb->csum = csum_block_add(skb->csum, csum, offset);
+ } else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
+ if (!access_ok(VERIFY_READ, from, copy) ||
+ __copy_from_user_nocache(to, from, copy))
+ return -EFAULT;
+ } else if (copy_from_user(to, from, copy))
+ return -EFAULT;
+
+ return 0;
+}
+
+static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
+ char __user *from, int copy)
+{
+ int err, offset = skb->len;
+
+ err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
+ copy, offset);
+ if (err)
+ __skb_trim(skb, offset);
+
+ return err;
+}
+
+static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from,
+ struct sk_buff *skb,
+ struct page *page,
+ int off, int copy)
+{
+ int err;
+
+ err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
+ copy, skb->len);
+ if (err)
+ return err;
+
+ skb->len += copy;
+ skb->data_len += copy;
+ skb->truesize += copy;
+ sk->sk_wmem_queued += copy;
+ sk_mem_charge(sk, copy);
+ return 0;
+}
+