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>

1 files changed, 25 insertions, 17 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3cb273ac8821..41fa5df9abbc 100644
--- 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;
 }