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| author | Eric Dumazet <edumazet@google.com> | 2014-09-30 00:29:15 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-10-02 00:34:25 +0400 |
| commit | d0bf4a9e92b9a93ffeeacbd7b6cb83e0ee3dc2ef (patch) | |
| tree | 1ba29128caa07307632b6219c1692308ec89983a /net/core/skbuff.c | |
| parent | b248230c34970a6c1c17c591d63b464e8d2cfc33 (diff) | |
| download | linux-d0bf4a9e92b9a93ffeeacbd7b6cb83e0ee3dc2ef.tar.xz | |
net: cleanup and document skb fclone layout
Lets use a proper structure to clearly document and implement
skb fast clones.
Then, we might experiment more easily alternative layouts.
This patch adds a new skb_fclone_busy() helper, used by tcp and xfrm,
to stop leaking of implementation details.
Signed-off-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 | 41 |
1 files changed, 20 insertions, 21 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 4be570a4ab21..a8cebb40699c 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -257,15 +257,16 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, kmemcheck_annotate_variable(shinfo->destructor_arg); if (flags & SKB_ALLOC_FCLONE) { - struct sk_buff *child = skb + 1; - atomic_t *fclone_ref = (atomic_t *) (child + 1); + struct sk_buff_fclones *fclones; - kmemcheck_annotate_bitfield(child, flags1); + fclones = container_of(skb, struct sk_buff_fclones, skb1); + + kmemcheck_annotate_bitfield(&fclones->skb2, flags1); skb->fclone = SKB_FCLONE_ORIG; - atomic_set(fclone_ref, 1); + atomic_set(&fclones->fclone_ref, 1); - child->fclone = SKB_FCLONE_UNAVAILABLE; - child->pfmemalloc = pfmemalloc; + fclones->skb2.fclone = SKB_FCLONE_UNAVAILABLE; + fclones->skb2.pfmemalloc = pfmemalloc; } out: return skb; @@ -524,8 +525,7 @@ static void skb_release_data(struct sk_buff *skb) */ static void kfree_skbmem(struct sk_buff *skb) { - struct sk_buff *other; - atomic_t *fclone_ref; + struct sk_buff_fclones *fclones; switch (skb->fclone) { case SKB_FCLONE_UNAVAILABLE: @@ -533,22 +533,21 @@ static void kfree_skbmem(struct sk_buff *skb) break; case SKB_FCLONE_ORIG: - fclone_ref = (atomic_t *) (skb + 2); - if (atomic_dec_and_test(fclone_ref)) - kmem_cache_free(skbuff_fclone_cache, skb); + fclones = container_of(skb, struct sk_buff_fclones, skb1); + if (atomic_dec_and_test(&fclones->fclone_ref)) + kmem_cache_free(skbuff_fclone_cache, fclones); break; case SKB_FCLONE_CLONE: - fclone_ref = (atomic_t *) (skb + 1); - other = skb - 1; + fclones = container_of(skb, struct sk_buff_fclones, skb2); /* The clone portion is available for * fast-cloning again. */ skb->fclone = SKB_FCLONE_UNAVAILABLE; - if (atomic_dec_and_test(fclone_ref)) - kmem_cache_free(skbuff_fclone_cache, other); + if (atomic_dec_and_test(&fclones->fclone_ref)) + kmem_cache_free(skbuff_fclone_cache, fclones); break; } } @@ -859,17 +858,18 @@ EXPORT_SYMBOL_GPL(skb_copy_ubufs); struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) { - struct sk_buff *n; + struct sk_buff_fclones *fclones = container_of(skb, + struct sk_buff_fclones, + skb1); + struct sk_buff *n = &fclones->skb2; if (skb_orphan_frags(skb, gfp_mask)) return NULL; - n = skb + 1; if (skb->fclone == SKB_FCLONE_ORIG && n->fclone == SKB_FCLONE_UNAVAILABLE) { - atomic_t *fclone_ref = (atomic_t *) (n + 1); n->fclone = SKB_FCLONE_CLONE; - atomic_inc(fclone_ref); + atomic_inc(&fclones->fclone_ref); } else { if (skb_pfmemalloc(skb)) gfp_mask |= __GFP_MEMALLOC; @@ -3240,8 +3240,7 @@ void __init skb_init(void) SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache", - (2*sizeof(struct sk_buff)) + - sizeof(atomic_t), + sizeof(struct sk_buff_fclones), 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |