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authorAlexander Duyck <alexander.h.duyck@intel.com>2012-05-04 14:26:46 +0000
committerDavid S. Miller <davem@davemloft.net>2012-05-06 13:13:19 -0400
commit9202e31d4632d82bd713fbd7d3fd229c0cd5b9cf (patch)
treeb56378a2c426de615808b32e195b77623d664b3b /net/core
parentbd14b1b2e29bd6812597f896dde06eaf7c6d2f24 (diff)
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')
-rw-r--r--net/core/skbuff.c12
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;