path: root/include
diff options
authorHerbert Xu <herbert@gondor.apana.org.au>2007-11-14 15:45:21 -0800
committerDavid S. Miller <davem@davemloft.net>2007-11-14 15:45:21 -0800
commitfb93134dfc2a6e6fbedc7c270a31da03fce88db9 (patch)
tree92c6d19049162f2f3eb9348a3159b5d0874a9daf /include
parent[S2IO]: Fixed memory leak when MSI-X vector allocation fails (diff)
[TCP]: Fix size calculation in sk_stream_alloc_pskb
We round up the header size in sk_stream_alloc_pskb so that TSO packets get zero tail room. Unfortunately this rounding up is not coordinated with the select_size() function used by TCP to calculate the second parameter of sk_stream_alloc_pskb. As a result, we may allocate more than a page of data in the non-TSO case when exactly one page is desired. In fact, rounding up the head room is detrimental in the non-TSO case because it makes memory that would otherwise be available to the payload head room. TSO doesn't need this either, all it wants is the guarantee that there is no tail room. So this patch fixes this by adjusting the skb_reserve call so that exactly the requested amount (which all callers have calculated in a precise way) is made available as tail room. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
1 files changed, 6 insertions, 4 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index 5504fb9fa88a..567e468d7492 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1235,14 +1235,16 @@ static inline struct sk_buff *sk_stream_alloc_pskb(struct sock *sk,
gfp_t gfp)
struct sk_buff *skb;
- int hdr_len;
- hdr_len = SKB_DATA_ALIGN(sk->sk_prot->max_header);
- skb = alloc_skb_fclone(size + hdr_len, gfp);
+ skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
if (skb) {
skb->truesize += mem;
if (sk_stream_wmem_schedule(sk, skb->truesize)) {
- skb_reserve(skb, hdr_len);
+ /*
+ * Make sure that we have exactly size bytes
+ * available to the caller, no more, no less.
+ */
+ skb_reserve(skb, skb_tailroom(skb) - size);
return skb;