tcp: Move code related to head frag in tcp_try_coalesce

This change reorders the code related to the use of an skb->head_frag so it
is placed before we check the rest of the frags.  This allows the code to
read more linearly instead of like some sort of loop.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3cb273ac88213777f97468752de42071242e84f4..41fa5df9abbc6a5edaf17399d4c522680d45e155 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4562,9 +4562,31 @@ merge:
        if (skb_has_frag_list(to) || skb_has_frag_list(from))
                return false;
 
-       if (skb_headlen(from) == 0 &&
-           (skb_shinfo(to)->nr_frags +
-            skb_shinfo(from)->nr_frags <= MAX_SKB_FRAGS)) {
+       if (skb_headlen(from) != 0) {
+               struct page *page;
+               unsigned int offset;
+
+               if (skb_shinfo(to)->nr_frags +
+                   skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
+                       return false;
+
+               if (!from->head_frag || skb_cloned(from))
+                       return false;
+
+               delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
+
+               page = virt_to_head_page(from->head);
+               offset = from->data - (unsigned char *)page_address(page);
+
+               skb_fill_page_desc(to, skb_shinfo(to)->nr_frags,
+                                  page, offset, skb_headlen(from));
+               *fragstolen = true;
+               goto copyfrags;
+       } else {
+               if (skb_shinfo(to)->nr_frags +
+                   skb_shinfo(from)->nr_frags > MAX_SKB_FRAGS)
+                       return false;
+
                delta = from->truesize -
                        SKB_TRUESIZE(skb_end_pointer(from) - from->head);
 copyfrags:
@@ -4587,20 +4609,6 @@ copyfrags:
                to->data_len += len;
                goto merge;
        }
-       if (from->head_frag && !skb_cloned(from)) {
-               struct page *page;
-               unsigned int offset;
-
-               if (skb_shinfo(to)->nr_frags + skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS)
-                       return false;
-               page = virt_to_head_page(from->head);
-               offset = from->data - (unsigned char *)page_address(page);
-               skb_fill_page_desc(to, skb_shinfo(to)->nr_frags,
-                                  page, offset, skb_headlen(from));
-               *fragstolen = true;
-               delta = from->truesize - SKB_DATA_ALIGN(sizeof(struct sk_buff));
-               goto copyfrags;
-       }
        return false;
 }