From 3e24591a19bbda6fcb2cbe383b41b4ba794501bf Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Fri, 4 May 2012 14:26:51 +0000 Subject: skb: Drop "fastpath" variable for skb_cloned check in pskb_expand_head Since there is now only one spot that actually uses "fastpath" there isn't much point in carrying it. Instead we can just use a check for skb_cloned to verify if we can perform the fast-path free for the head or not. Signed-off-by: Alexander Duyck Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/skbuff.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) (limited to 'net') diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 4d085d454285..17e4b1e1bf2c 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -932,7 +932,6 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, u8 *data; int size = nhead + (skb_end_pointer(skb) - skb->head) + ntail; long off; - bool fastpath; BUG_ON(nhead < 0); @@ -941,16 +940,6 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, size = SKB_DATA_ALIGN(size); - /* Check if we can avoid taking references on fragments if we own - * the last reference on skb->head. (see skb_release_data()) - */ - if (!skb->cloned) - fastpath = true; - else { - int delta = skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1; - fastpath = atomic_read(&skb_shinfo(skb)->dataref) == delta; - } - data = kmalloc(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)), gfp_mask); if (!data) @@ -966,9 +955,12 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, skb_shinfo(skb), offsetof(struct skb_shared_info, frags[skb_shinfo(skb)->nr_frags])); - if (fastpath) { - skb_free_head(skb); - } else { + /* + * if shinfo is shared we must drop the old head gracefully, but if it + * is not we can just drop the old head and let the existing refcount + * be since all we did is relocate the values + */ + if (skb_cloned(skb)) { /* copy this zero copy skb frags */ if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) { if (skb_copy_ubufs(skb, gfp_mask)) @@ -981,6 +973,8 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, skb_clone_fraglist(skb); skb_release_data(skb); + } else { + skb_free_head(skb); } off = (data + nhead) - skb->head; -- cgit v1.2.1