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Message-ID: <20150722131839.GB18037@gmail.com>
Date: Wed, 22 Jul 2015 22:18:39 +0900
From: Ken-ichirou MATSUZAWA <chamaken@...il.com>
To: netdev@...r.kernel.org
Subject: [RFC PATCH 1/5] netlink: mmap: introduce mmaped skb helper functions
It seems that we need helper functions for skb which is allocated
at netlink_alloc_skb() since it does not have skb_shared_info.
Signed-off-by: Ken-ichirou MATSUZAWA <chamas@...dion.ne.jp>
---
include/linux/netlink.h | 22 ++++---------
net/netlink/af_netlink.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 87 insertions(+), 16 deletions(-)
diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index 6835c12..049962e 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -68,6 +68,12 @@ extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
extern int netlink_has_listeners(struct sock *sk, unsigned int group);
extern struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
u32 dst_portid, gfp_t gfp_mask);
+extern struct sk_buff *netlink_skb_copy(const struct sk_buff *skb, gfp_t gfp_mask);
+extern struct sk_buff *netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask);
+extern int netlink_skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen);
+extern void netlink_free_skb(struct sk_buff *skb);
+void netlink_consume_skb(struct sk_buff *skb);
+
extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
__u32 group, gfp_t allocation);
@@ -86,22 +92,6 @@ int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
int netlink_sendskb(struct sock *sk, struct sk_buff *skb);
-static inline struct sk_buff *
-netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
-{
- struct sk_buff *nskb;
-
- nskb = skb_clone(skb, gfp_mask);
- if (!nskb)
- return NULL;
-
- /* This is a large skb, set destructor callback to release head */
- if (is_vmalloc_addr(skb->head))
- nskb->destructor = skb->destructor;
-
- return nskb;
-}
-
/*
* skb should fit one page. This choice is good for headerless malloc.
* But we should limit to 8K so that userspace does not have to
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index bf6e766..a0a32f4 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -1872,6 +1872,87 @@ out:
}
EXPORT_SYMBOL_GPL(netlink_alloc_skb);
+struct sk_buff *netlink_skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
+{
+#ifdef CONFIG_NETLINK_MMAP
+ if (netlink_skb_is_mmaped(skb)) {
+ struct sk_buff *n = alloc_skb(skb->len, gfp_mask);
+ if (!n)
+ return NULL;
+
+ skb_put(n, skb->len);
+ memcpy(n->data, skb->data, skb->len);
+ return n;
+ } else
+#endif
+ return skb_copy(skb, gfp_mask);
+}
+EXPORT_SYMBOL_GPL(netlink_skb_copy);
+
+struct sk_buff *netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
+{
+ struct sk_buff *nskb;
+
+#ifdef CONFIG_NETLINK_MMAP
+ if (netlink_skb_is_mmaped(skb))
+ return netlink_skb_copy(skb, gfp_mask);
+#endif
+ nskb = skb_clone(skb, gfp_mask);
+ if (!nskb)
+ return NULL;
+
+ /* This is a large skb, set destructor callback to release head */
+ if (is_vmalloc_addr(skb->head))
+ nskb->destructor = skb->destructor;
+
+ return nskb;
+}
+EXPORT_SYMBOL_GPL(netlink_skb_clone);
+
+int
+netlink_skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen)
+{
+#ifdef CONFIG_NETLINK_MMAP
+ struct page *page;
+ unsigned int offset;
+
+ if (netlink_skb_is_mmaped(from)) {
+ if (!len)
+ return 0;
+
+ page = virt_to_head_page(from->head);
+ offset = from->data - (unsigned char *)page_address(page);
+ __skb_fill_page_desc(to, 0, page, offset, len);
+ get_page(page);
+ to->truesize += len;
+ to->len += len;
+ to->data_len += len;
+
+ return 0;
+ } else
+#endif
+
+ return skb_zerocopy(to, from, len, hlen);
+}
+EXPORT_SYMBOL_GPL(netlink_skb_zerocopy);
+
+void netlink_free_skb(struct sk_buff *skb)
+{
+ kfree_skb_partial(skb, netlink_skb_is_mmaped(skb));
+}
+EXPORT_SYMBOL_GPL(netlink_free_skb);
+
+void netlink_consume_skb(struct sk_buff *skb)
+{
+#ifdef CONFIG_NETLINK_MMAP
+ if (netlink_skb_is_mmaped(skb))
+ kfree_skb_partial(skb, true);
+ else
+#endif
+ consume_skb(skb);
+}
+EXPORT_SYMBOL_GPL(netlink_consume_skb);
+
int netlink_has_listeners(struct sock *sk, unsigned int group)
{
int res = 0;
--
1.7.10.4
----- End forwarded message -----
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