inet: Decrease overhead of on-stack inet_cork.

When we fast path datagram sends to avoid locking by putting
the inet_cork on the stack we use up lots of space that isn't
necessary.

This is because inet_cork contains a "struct flowi" which isn't
used in these code paths.

Split inet_cork to two parts, "inet_cork" and "inet_cork_full".
Only the latter of which has the "struct flowi" and is what is
stored in inet_sock.

Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index ed2ba6eca724..caaff5f5f39f 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -96,17 +96,21 @@ static inline struct inet_request_sock *inet_rsk(const struct request_sock *sk)
 
 struct inet_cork {
         unsigned int            flags;
-        unsigned int            fragsize;
+        __be32                  addr;
         struct ip_options       *opt;
+        unsigned int            fragsize;
         struct dst_entry        *dst;
         int                     length; /* Total length of all frames */
-        __be32                  addr;
-        struct flowi            fl;
         struct page             *page;
         u32                     off;
         u8                      tx_flags;
 };
 
+struct inet_cork_full {
+        struct inet_cork        base;
+        struct flowi            fl;
+};
+
 struct ip_mc_socklist;
 struct ipv6_pinfo;
 struct rtable;
@@ -164,7 +168,7 @@ struct inet_sock {
         int                     mc_index;
         __be32                  mc_addr;
         struct ip_mc_socklist __rcu     *mc_list;
-        struct inet_cork        cork;
+        struct inet_cork_full   cork;
 };
 
 #define IPCORK_OPT      1       /* ip-options has been held in ipcork.opt */