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Commit f78a5fda authored by David S. Miller's avatar David S. Miller
Browse files

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



This reverts commit 0856a304.

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: default avatarDavid S. Miller <davem@davemloft.net>
parent 473e64ee

include/net/scm.h

+3 −19
Original line number Diff line number Diff line
@@ -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)

net/unix/af_unix.c

+16 −29
Original line number Diff line number Diff line
@@ -1378,17 +1378,11 @@ static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb) 
	return max_level;

}



static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb,

			   bool send_fds, bool ref)

static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)

{

	int err = 0;

	if (ref) {

	UNIXCB(skb).pid  = get_pid(scm->pid);

	UNIXCB(skb).cred = get_cred(scm->cred);

	} else {

		UNIXCB(skb).pid  = scm->pid;

		UNIXCB(skb).cred = scm->cred;

	}

	UNIXCB(skb).fp = NULL;

	if (scm->fp && send_fds)

		err = unix_attach_fds(scm, skb);
@@ -1413,7 +1407,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 
	int namelen = 0; /* fake GCC */

	int err;

	unsigned hash;

	struct sk_buff *skb = NULL;

	struct sk_buff *skb;

	long timeo;

	struct scm_cookie tmp_scm;

	int max_level;
@@ -1454,7 +1448,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 
	if (skb == NULL)

		goto out;



	err = unix_scm_to_skb(siocb->scm, skb, true, false);

	err = unix_scm_to_skb(siocb->scm, skb, true);

	if (err < 0)

		goto out_free;

	max_level = err + 1;
@@ -1550,7 +1544,7 @@ restart: 
	unix_state_unlock(other);

	other->sk_data_ready(other, len);

	sock_put(other);

	scm_release(siocb->scm);

	scm_destroy(siocb->scm);

	return len;



out_unlock:
@@ -1560,7 +1554,6 @@ out_free: 
out:

	if (other)

		sock_put(other);

	if (skb == NULL)

	scm_destroy(siocb->scm);

	return err;

}
@@ -1573,7 +1566,7 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 
	struct sock *sk = sock->sk;

	struct sock *other = NULL;

	int err, size;

	struct sk_buff *skb = NULL;

	struct sk_buff *skb;

	int sent = 0;

	struct scm_cookie tmp_scm;

	bool fds_sent = false;
@@ -1638,11 +1631,11 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 
		size = min_t(int, size, skb_tailroom(skb));





		/* Only send the fds and no ref to pid in the first buffer */

		err = unix_scm_to_skb(siocb->scm, skb, !fds_sent, fds_sent);

		/* Only send the fds in the first buffer */

		err = unix_scm_to_skb(siocb->scm, skb, !fds_sent);

		if (err < 0) {

			kfree_skb(skb);

			goto out;

			goto out_err;

		}

		max_level = err + 1;

		fds_sent = true;
@@ -1650,7 +1643,7 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 
		err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);

		if (err) {

			kfree_skb(skb);

			goto out;

			goto out_err;

		}



		unix_state_lock(other);
@@ -1667,9 +1660,6 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock, 
		sent += size;

	}



	if (skb)

		scm_release(siocb->scm);

	else

	scm_destroy(siocb->scm);

	siocb->scm = NULL;
@@ -1683,9 +1673,7 @@ pipe_err: 
		send_sig(SIGPIPE, current, 0);

	err = -EPIPE;

out_err:

	if (skb == NULL)

	scm_destroy(siocb->scm);

out:

	siocb->scm = NULL;

	return sent ? : err;

}
@@ -1789,7 +1777,7 @@ static int unix_dgram_recvmsg(struct kiocb *iocb, struct socket *sock, 
		siocb->scm = &tmp_scm;

		memset(&tmp_scm, 0, sizeof(tmp_scm));

	}

	scm_set_cred_noref(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);

	scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);

	unix_set_secdata(siocb->scm, skb);



	if (!(flags & MSG_PEEK)) {
@@ -1951,8 +1939,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock, 
			}

		} else {

			/* Copy credentials */

			scm_set_cred_noref(siocb->scm, UNIXCB(skb).pid,

					   UNIXCB(skb).cred);

			scm_set_cred(siocb->scm, UNIXCB(skb).pid, UNIXCB(skb).cred);

			check_creds = 1;

		}