[PATCH v3 net-next 1/4] net: skbuff: add skb_append_pagefrags and use it

[Hannes Frederic Sowa]

Signed-off-by: Hannes Frederic Sowa <han...@stressinduktion.org>
Acked-by: Eric Dumazet <eduma...@google.com>
---
v2:
* remove now unused variable i in ip_append_page (thanks, Cong!)
* switched to EXPORT_SYMBOL_GPL for skb_append_pagefrags

v3:
* unchanged

 include/linux/skbuff.h |  3 +++
 net/core/skbuff.c      | 18 ++++++++++++++++++
 net/ipv4/ip_output.c   | 15 ++++-----------
 3 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 40960fe..b9d267b 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -860,6 +860,9 @@ int skb_append_datato_frags(struct sock *sk, struct sk_buff 
*skb,
                                        int len, int odd, struct sk_buff *skb),
                            void *from, int length);
 
+int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
+                        int offset, size_t size);
+
 struct skb_seq_state {
        __u32           lower_offset;
        __u32           upper_offset;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index f3fe9bd..4f2babe 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2915,6 +2915,24 @@ int skb_append_datato_frags(struct sock *sk, struct 
sk_buff *skb,
 }
 EXPORT_SYMBOL(skb_append_datato_frags);
 
+int skb_append_pagefrags(struct sk_buff *skb, struct page *page,
+                        int offset, size_t size)
+{
+       int i = skb_shinfo(skb)->nr_frags;
+
+       if (skb_can_coalesce(skb, i, page, offset)) {
+               skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
+       } else if (i < MAX_SKB_FRAGS) {
+               get_page(page);
+               skb_fill_page_desc(skb, i, page, offset, size);
+       } else {
+               return -EMSGSIZE;
+       }
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(skb_append_pagefrags);
+
 /**
  *     skb_pull_rcsum - pull skb and update receive checksum
  *     @skb: buffer to update
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 8d91b92..451b009 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1233,11 +1233,9 @@ ssize_t  ip_append_page(struct sock *sk, struct flowi4 
*fl4, struct page *page,
        }
 
        while (size > 0) {
-               int i;
-
-               if (skb_is_gso(skb))
+               if (skb_is_gso(skb)) {
                        len = size;
-               else {
+               } else {
 
                        /* Check if the remaining data fits into current 
packet. */
                        len = mtu - skb->len;
@@ -1289,15 +1287,10 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 
*fl4, struct page *page,
                        continue;
                }
 
-               i = skb_shinfo(skb)->nr_frags;
                if (len > size)
                        len = size;
-               if (skb_can_coalesce(skb, i, page, offset)) {
-                       skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len);
-               } else if (i < MAX_SKB_FRAGS) {
-                       get_page(page);
-                       skb_fill_page_desc(skb, i, page, offset, len);
-               } else {
+
+               if (skb_append_pagefrags(skb, page, offset, len)) {
                        err = -EMSGSIZE;
                        goto error;
                }
-- 
2.1.0

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