| Message ID | 20120503110942.18281.27820.stgit@gitlad.jf.intel.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Thu, 2012-05-03 at 04:09 -0700, Alexander Duyck wrote: > This patch adds support for a skb_head_is_locked helper function. It is > meant to be used any time we are considering transferring the head from > skb->head to a paged frag. If the head is locked it means we cannot remove > the head from the skb so it must be copied or we must take the skb as a > whole. > > Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> > --- Acked-by: Eric Dumazet <edumazet@google.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Alexander Duyck <alexander.h.duyck@intel.com> Date: Thu, 03 May 2012 04:09:42 -0700 > This patch adds support for a skb_head_is_locked helper function. It is > meant to be used any time we are considering transferring the head from > skb->head to a paged frag. If the head is locked it means we cannot remove > the head from the skb so it must be copied or we must take the skb as a > whole. > > Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Thanks for following up on this instead of going to sleep :-) Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 988fc49..37f5391 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2566,5 +2566,19 @@ static inline bool skb_is_recycleable(const struct sk_buff *skb, int skb_size) return true; } + +/** + * skb_head_is_locked - Determine if the skb->head is locked down + * @skb: skb to check + * + * The head on skbs build around a head frag can be removed if they are + * not cloned. This function returns true if the skb head is locked down + * due to either being allocated via kmalloc, or by being a clone with + * multiple references to the head. + */ +static inline bool skb_head_is_locked(const struct sk_buff *skb) +{ + return !skb->head_frag || skb_cloned(skb); +} #endif /* __KERNEL__ */ #endif /* _LINUX_SKBUFF_H */ diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 9e8caa0..dc514e3 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1699,7 +1699,6 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, struct splice_pipe_desc *spd, struct sock *sk) { int seg; - bool head_is_locked = !skb->head_frag || skb_cloned(skb); /* map the linear part : * If skb->head_frag is set, this 'linear' part is backed by a @@ -1710,7 +1709,7 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, (unsigned long) skb->data & (PAGE_SIZE - 1), skb_headlen(skb), offset, len, skb, spd, - head_is_locked, + skb_head_is_locked(skb), sk, pipe)) return true; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 84e69e0..7b2d351 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4568,7 +4568,7 @@ static bool tcp_try_coalesce(struct sock *sk, skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) return false; - if (!from->head_frag || skb_cloned(from)) + if (skb_head_is_locked(from)) return false; delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
This patch adds support for a skb_head_is_locked helper function. It is meant to be used any time we are considering transferring the head from skb->head to a paged frag. If the head is locked it means we cannot remove the head from the skb so it must be copied or we must take the skb as a whole. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> --- include/linux/skbuff.h | 14 ++++++++++++++ net/core/skbuff.c | 3 +-- net/ipv4/tcp_input.c | 2 +- 3 files changed, 16 insertions(+), 3 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html