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| author | Alexander Duyck <alexander.h.duyck@intel.com> | 2012-05-04 14:26:46 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-05-06 13:13:19 -0400 |
| commit | 9202e31d4632d82bd713fbd7d3fd229c0cd5b9cf (patch) | |
| tree | b56378a2c426de615808b32e195b77623d664b3b /net/core/skbuff.c | |
| parent | bd14b1b2e29bd6812597f896dde06eaf7c6d2f24 (diff) | |
| download | blackbird-op-linux-9202e31d4632d82bd713fbd7d3fd229c0cd5b9cf.tar.gz blackbird-op-linux-9202e31d4632d82bd713fbd7d3fd229c0cd5b9cf.zip | |
skb: Drop bad code from pskb_expand_head
The fast-path for pskb_expand_head contains a check where the size plus the
unaligned size of skb_shared_info is compared against the size of the data
buffer. This code path has two issues. First is the fact that after the
recent changes by Eric Dumazet to __alloc_skb and build_skb the shared info
is always placed in the optimal spot for a buffer size making this check
unnecessary. The second issue is the fact that the check doesn't take into
account the aligned size of shared info. As a result the code burns cycles
doing a memcpy with nothing actually being shifted.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/skbuff.c')
| -rw-r--r-- | net/core/skbuff.c | 12 |
1 files changed, 0 insertions, 12 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index c199aa428c6d..4d085d454285 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -951,17 +951,6 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, fastpath = atomic_read(&skb_shinfo(skb)->dataref) == delta; } - if (fastpath && !skb->head_frag && - size + sizeof(struct skb_shared_info) <= ksize(skb->head)) { - memmove(skb->head + size, skb_shinfo(skb), - offsetof(struct skb_shared_info, - frags[skb_shinfo(skb)->nr_frags])); - memmove(skb->head + nhead, skb->head, - skb_tail_pointer(skb) - skb->head); - off = nhead; - goto adjust_others; - } - data = kmalloc(size + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)), gfp_mask); if (!data) @@ -997,7 +986,6 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, skb->head = data; skb->head_frag = 0; -adjust_others: skb->data += off; #ifdef NET_SKBUFF_DATA_USES_OFFSET skb->end = size; |
