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[NET]: Use non-recursive algorithm in skb_copy_datagram_iovec()
Use iteration instead of recursion. Fraglists within fraglists should never occur, so we BUG check this. Signed-off-by: Daniel Phillips <phillips@istop.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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95001ee925
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bc8dfcb939
@ -211,74 +211,45 @@ void skb_free_datagram(struct sock *sk, struct sk_buff *skb)
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int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset,
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struct iovec *to, int len)
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{
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int start = skb_headlen(skb);
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int i, copy = start - offset;
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int i, err, fraglen, end = 0;
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struct sk_buff *next = skb_shinfo(skb)->frag_list;
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next_skb:
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fraglen = skb_headlen(skb);
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i = -1;
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/* Copy header. */
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if (copy > 0) {
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if (copy > len)
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copy = len;
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if (memcpy_toiovec(to, skb->data + offset, copy))
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goto fault;
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if ((len -= copy) == 0)
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return 0;
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offset += copy;
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}
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while (1) {
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int start = end;
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/* Copy paged appendix. Hmm... why does this look so complicated? */
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for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
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int end;
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BUG_TRAP(start <= offset + len);
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end = start + skb_shinfo(skb)->frags[i].size;
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if ((copy = end - offset) > 0) {
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int err;
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u8 *vaddr;
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skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
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struct page *page = frag->page;
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if ((end += fraglen) > offset) {
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int copy = end - offset, o = offset - start;
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if (copy > len)
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copy = len;
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vaddr = kmap(page);
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err = memcpy_toiovec(to, vaddr + frag->page_offset +
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offset - start, copy);
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kunmap(page);
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if (i == -1)
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err = memcpy_toiovec(to, skb->data + o, copy);
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else {
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skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
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struct page *page = frag->page;
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void *p = kmap(page) + frag->page_offset + o;
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err = memcpy_toiovec(to, p, copy);
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kunmap(page);
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}
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if (err)
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goto fault;
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if (!(len -= copy))
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return 0;
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offset += copy;
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}
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start = end;
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if (++i >= skb_shinfo(skb)->nr_frags)
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break;
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fraglen = skb_shinfo(skb)->frags[i].size;
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}
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if (skb_shinfo(skb)->frag_list) {
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struct sk_buff *list = skb_shinfo(skb)->frag_list;
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for (; list; list = list->next) {
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int end;
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BUG_TRAP(start <= offset + len);
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end = start + list->len;
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if ((copy = end - offset) > 0) {
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if (copy > len)
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copy = len;
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if (skb_copy_datagram_iovec(list,
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offset - start,
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to, copy))
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goto fault;
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if ((len -= copy) == 0)
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return 0;
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offset += copy;
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}
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start = end;
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}
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if (next) {
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skb = next;
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BUG_ON(skb_shinfo(skb)->frag_list);
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next = skb->next;
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goto next_skb;
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}
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if (!len)
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return 0;
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fault:
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return -EFAULT;
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}
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