[PATCHv3 1/6] skbuff: add an api to orphan frags

From: Michael S. Tsirkin
Date: Fri Jul 20 2012 - 15:22:32 EST


Many places do
if ((skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY))
skb_copy_ubufs(skb, gfp_mask);
to copy and invoke frag destructors if necessary.
Add an inline helper for this.

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
include/linux/skbuff.h | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 642cb73..d205c4b 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1667,6 +1667,22 @@ static inline void skb_orphan(struct sk_buff *skb)
}

/**
+ * skb_orphan_frags - orphan the frags contained in a buffer
+ * @skb: buffer to orphan frags from
+ * @gfp_mask: allocation mask for replacement pages
+ *
+ * For each frag in the SKB which needs a destructor (i.e. has an
+ * owner) create a copy of that frag and release the original
+ * page by calling the destructor.
+ */
+static inline int skb_orphan_frags(struct sk_buff *skb, gfp_t gfp_mask)
+{
+ if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY)))
+ return 0;
+ return skb_copy_ubufs(skb, gfp_mask);
+}
+
+/**
* __skb_queue_purge - empty a list
* @list: list to empty
*
--
MST

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