From c8753d55afb436fd6a25c8bbe8d783f6dcf1c9f8 Mon Sep 17 00:00:00 2001 From: Vijay Subramanian Date: Thu, 2 Oct 2014 10:00:43 -0700 Subject: [PATCH] net: Cleanup skb cloning by adding SKB_FCLONE_FREE SKB_FCLONE_UNAVAILABLE has overloaded meaning depending on type of skb. 1: If skb is allocated from head_cache, it indicates fclone is not available. 2: If skb is a companion fclone skb (allocated from fclone_cache), it indicates it is available to be used. To avoid confusion for case 2 above, this patch replaces SKB_FCLONE_UNAVAILABLE with SKB_FCLONE_FREE where appropriate. For fclone companion skbs, this indicates it is free for use. SKB_FCLONE_UNAVAILABLE will now simply indicate skb is from head_cache and cannot / will not have a companion fclone. Signed-off-by: Vijay Subramanian Signed-off-by: David S. Miller --- include/linux/skbuff.h | 7 ++++--- net/core/skbuff.c | 8 ++++---- 2 files changed, 8 insertions(+), 7 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 7c5036d11fe..3a5ec763862 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -339,9 +339,10 @@ struct skb_shared_info { enum { - SKB_FCLONE_UNAVAILABLE, - SKB_FCLONE_ORIG, - SKB_FCLONE_CLONE, + SKB_FCLONE_UNAVAILABLE, /* skb has no fclone (from head_cache) */ + SKB_FCLONE_ORIG, /* orig skb (from fclone_cache) */ + SKB_FCLONE_CLONE, /* companion fclone skb (from fclone_cache) */ + SKB_FCLONE_FREE, /* this companion fclone skb is available */ }; enum { diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a0b312fa304..28916e47f95 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -265,7 +265,7 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, skb->fclone = SKB_FCLONE_ORIG; atomic_set(&fclones->fclone_ref, 1); - fclones->skb2.fclone = SKB_FCLONE_UNAVAILABLE; + fclones->skb2.fclone = SKB_FCLONE_FREE; fclones->skb2.pfmemalloc = pfmemalloc; } out: @@ -542,7 +542,7 @@ static void kfree_skbmem(struct sk_buff *skb) fclones = container_of(skb, struct sk_buff_fclones, skb2); /* Warning : We must perform the atomic_dec_and_test() before - * setting skb->fclone back to SKB_FCLONE_UNAVAILABLE, otherwise + * setting skb->fclone back to SKB_FCLONE_FREE, otherwise * skb_clone() could set clone_ref to 2 before our decrement. * Anyway, if we are going to free the structure, no need to * rewrite skb->fclone. @@ -553,7 +553,7 @@ static void kfree_skbmem(struct sk_buff *skb) /* The clone portion is available for * fast-cloning again. */ - skb->fclone = SKB_FCLONE_UNAVAILABLE; + skb->fclone = SKB_FCLONE_FREE; } break; } @@ -874,7 +874,7 @@ struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask) return NULL; if (skb->fclone == SKB_FCLONE_ORIG && - n->fclone == SKB_FCLONE_UNAVAILABLE) { + n->fclone == SKB_FCLONE_FREE) { n->fclone = SKB_FCLONE_CLONE; /* As our fastclone was free, clone_ref must be 1 at this point. * We could use atomic_inc() here, but it is faster -- 2.41.0