Revert "Scm: Remove unnecessary pid & credential references in Unix socket's send and receive path"

This reverts commit 0856a304091b33a8e8f9f9c98e776f425af2b625.

As requested by Eric Dumazet, it has various ref-counting
problems and has introduced regressions.  Eric will add
a more suitable version of this performance fix.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 19 deletions

diff --git a/include/net/scm.h b/include/net/scm.h
index 68e1e481658e..745460fa2f02 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -53,14 +53,6 @@ static __inline__ void scm_set_cred(struct scm_cookie *scm,
         cred_to_ucred(pid, cred, &scm->creds);
 }
 
-static __inline__ void scm_set_cred_noref(struct scm_cookie *scm,
-                                    struct pid *pid, const struct cred *cred)
-{
-        scm->pid  = pid;
-        scm->cred = cred;
-        cred_to_ucred(pid, cred, &scm->creds);
-}
-
 static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
 {
         put_pid(scm->pid);
@@ -78,15 +70,6 @@ static __inline__ void scm_destroy(struct scm_cookie *scm)
                 __scm_destroy(scm);
 }
 
-static __inline__ void scm_release(struct scm_cookie *scm)
-{
-        /* keep ref on pid and cred */
-        scm->pid = NULL;
-        scm->cred = NULL;
-        if (scm->fp)
-                __scm_destroy(scm);
-}
-
 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
                                struct scm_cookie *scm)
 {
@@ -125,14 +108,15 @@ static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
         if (!msg->msg_control) {
                 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
                         msg->msg_flags |= MSG_CTRUNC;
-                if (scm && scm->fp)
-                        __scm_destroy(scm);
+                scm_destroy(scm);
                 return;
         }
 
         if (test_bit(SOCK_PASSCRED, &sock->flags))
                 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
 
+        scm_destroy_cred(scm);
+
         scm_passec(sock, msg, scm);
 
         if (!scm->fp)