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)