skb: Add skb_head_is_locked helper function
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> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -2566,5 +2566,19 @@ static inline bool skb_is_recycleable(const struct sk_buff *skb, int skb_size)
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return true;
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}
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/**
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* skb_head_is_locked - Determine if the skb->head is locked down
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* @skb: skb to check
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*
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* The head on skbs build around a head frag can be removed if they are
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* not cloned. This function returns true if the skb head is locked down
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* due to either being allocated via kmalloc, or by being a clone with
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* multiple references to the head.
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*/
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static inline bool skb_head_is_locked(const struct sk_buff *skb)
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{
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return !skb->head_frag || skb_cloned(skb);
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}
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#endif /* __KERNEL__ */
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#endif /* _LINUX_SKBUFF_H */
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@ -1699,7 +1699,6 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
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struct splice_pipe_desc *spd, struct sock *sk)
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{
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int seg;
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bool head_is_locked = !skb->head_frag || skb_cloned(skb);
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/* map the linear part :
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* If skb->head_frag is set, this 'linear' part is backed by a
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@ -1710,7 +1709,7 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
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(unsigned long) skb->data & (PAGE_SIZE - 1),
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skb_headlen(skb),
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offset, len, skb, spd,
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head_is_locked,
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skb_head_is_locked(skb),
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sk, pipe))
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return true;
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@ -4568,7 +4568,7 @@ static bool tcp_try_coalesce(struct sock *sk,
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skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
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return false;
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if (!from->head_frag || skb_cloned(from))
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if (skb_head_is_locked(from))
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return false;
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delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
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