tcp_memcontrol: Cleanup/fix cg_proto->memory_pressure handling.

kill memcg_tcp_enter_memory_pressure.  The only function of
memcg_tcp_enter_memory_pressure was to reduce deal with the
unnecessary abstraction that was tcp_memcontrol.  Now that struct
tcp_memcontrol is gone remove this unnecessary function, the
unnecessary function pointer, and modify sk_enter_memory_pressure to
set this field directly, just as sk_leave_memory_pressure cleas this
field directly.

This fixes a small bug I intruduced when killing struct tcp_memcontrol
that caused memcg_tcp_enter_memory_pressure to never be called and
thus failed to ever set cg_proto->memory_pressure.

Remove the cg_proto enter_memory_pressure function as it now serves
no useful purpose.

Don't test cg_proto->memory_presser in sk_leave_memory_pressure before
clearing it.  The test was originally there to ensure that the pointer
was non-NULL.  Now that cg_proto is not a pointer the pointer does not
matter.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 4 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index e3a18ff0c38b..2ef3c3eca47a 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1035,7 +1035,6 @@ enum cg_proto_flags {
 };
 
 struct cg_proto {
-        void                    (*enter_memory_pressure)(struct sock *sk);
         struct res_counter      memory_allocated;       /* Current allocated memory. */
         struct percpu_counter   sockets_allocated;      /* Current number of sockets. */
         int                     memory_pressure;
@@ -1155,8 +1154,7 @@ static inline void sk_leave_memory_pressure(struct sock *sk)
                 struct proto *prot = sk->sk_prot;
 
                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
-                        if (cg_proto->memory_pressure)
-                                cg_proto->memory_pressure = 0;
+                        cg_proto->memory_pressure = 0;
         }
 
 }
@@ -1171,7 +1169,7 @@ static inline void sk_enter_memory_pressure(struct sock *sk)
                 struct proto *prot = sk->sk_prot;
 
                 for (; cg_proto; cg_proto = parent_cg_proto(prot, cg_proto))
-                        cg_proto->enter_memory_pressure(sk);
+                        cg_proto->memory_pressure = 1;
         }
 
         sk->sk_prot->enter_memory_pressure(sk);