Commit bc8dfcb9 by Daniel Phillips Committed by David S. Miller

### [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>```
parent 95001ee9
 ... @@ -211,74 +211,45 @@ void skb_free_datagram(struct sock *sk, struct sk_buff *skb) ... @@ -211,74 +211,45 @@ void skb_free_datagram(struct sock *sk, struct sk_buff *skb) int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset, int skb_copy_datagram_iovec(const struct sk_buff *skb, int offset, struct iovec *to, int len) struct iovec *to, int len) { { int start = skb_headlen(skb); int i, err, fraglen, end = 0; int i, copy = start - offset; struct sk_buff *next = skb_shinfo(skb)->frag_list; next_skb: /* Copy header. */ fraglen = skb_headlen(skb); if (copy > 0) { i = -1; if (copy > len) copy = len; if (memcpy_toiovec(to, skb->data + offset, copy)) goto fault; if ((len -= copy) == 0) return 0; offset += copy; } /* Copy paged appendix. Hmm... why does this look so complicated? */ while (1) { for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { int start = end; int end; BUG_TRAP(start <= offset + len); end = start + skb_shinfo(skb)->frags[i].size; if ((end += fraglen) > offset) { if ((copy = end - offset) > 0) { int copy = end - offset, o = offset - start; int err; u8 *vaddr; skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; struct page *page = frag->page; if (copy > len) if (copy > len) copy = len; copy = len; vaddr = kmap(page); if (i == -1) err = memcpy_toiovec(to, vaddr + frag->page_offset + err = memcpy_toiovec(to, skb->data + o, copy); offset - start, copy); else { kunmap(page); skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; struct page *page = frag->page; void *p = kmap(page) + frag->page_offset + o; err = memcpy_toiovec(to, p, copy); kunmap(page); } if (err) if (err) goto fault; goto fault; if (!(len -= copy)) if (!(len -= copy)) return 0; return 0; offset += copy; offset += copy; } } start = end; if (++i >= skb_shinfo(skb)->nr_frags) break; fraglen = skb_shinfo(skb)->frags[i].size; } } if (next) { if (skb_shinfo(skb)->frag_list) { skb = next; struct sk_buff *list = skb_shinfo(skb)->frag_list; BUG_ON(skb_shinfo(skb)->frag_list); next = skb->next; for (; list; list = list->next) { goto next_skb; int end; BUG_TRAP(start <= offset + len); end = start + list->len; if ((copy = end - offset) > 0) { if (copy > len) copy = len; if (skb_copy_datagram_iovec(list, offset - start, to, copy)) goto fault; if ((len -= copy) == 0) return 0; offset += copy; } start = end; } } } if (!len) return 0; fault: fault: return -EFAULT; return -EFAULT; } } ... ...
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