Commit 8b77338e authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

af_unix: Cache state->msg in unix_stream_read_generic(). 



In unix_stream_read_generic(), state->msg is fetched multiple times.

Let's cache it in a local variable.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250702223606.1054680-6-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f4e1fb04

net/unix/af_unix.c

+17 −16
Original line number Diff line number Diff line
@@ -2840,20 +2840,21 @@ static int unix_stream_read_skb(struct sock *sk, skb_read_actor_t recv_actor) 
static int unix_stream_read_generic(struct unix_stream_read_state *state,

				    bool freezable)

{

	struct scm_cookie scm;

	int noblock = state->flags & MSG_DONTWAIT;

	struct socket *sock = state->socket;

	struct msghdr *msg = state->msg;

	struct sock *sk = sock->sk;

	struct unix_sock *u = unix_sk(sk);

	int copied = 0;

	size_t size = state->size;

	int flags = state->flags;

	int noblock = flags & MSG_DONTWAIT;

	bool check_creds = false;

	int target;

	struct scm_cookie scm;

	unsigned int last_len;

	struct unix_sock *u;

	int copied = 0;

	int err = 0;

	long timeo;

	int target;

	int skip;

	size_t size = state->size;

	unsigned int last_len;



	if (unlikely(READ_ONCE(sk->sk_state) != TCP_ESTABLISHED)) {

		err = -EINVAL;
@@ -2873,6 +2874,8 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state, 


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



	u = unix_sk(sk);



	/* Lock the socket to prevent queue disordering

	 * while sleeps in memcpy_tomsg

	 */
@@ -2964,14 +2967,12 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state, 
		}



		/* Copy address just once */

		if (state->msg && state->msg->msg_name) {

			DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr,

					 state->msg->msg_name);

			unix_copy_addr(state->msg, skb->sk);

		if (msg && msg->msg_name) {

			DECLARE_SOCKADDR(struct sockaddr_un *, sunaddr, msg->msg_name);



			BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk,

							      state->msg->msg_name,

							      &state->msg->msg_namelen);

			unix_copy_addr(msg, skb->sk);

			BPF_CGROUP_RUN_PROG_UNIX_RECVMSG_LOCK(sk, msg->msg_name,

							      &msg->msg_namelen);



			sunaddr = NULL;

		}
@@ -3033,8 +3034,8 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state, 
	} while (size);



	mutex_unlock(&u->iolock);

	if (state->msg)

		scm_recv_unix(sock, state->msg, &scm, flags);

	if (msg)

		scm_recv_unix(sock, msg, &scm, flags);

	else

		scm_destroy(&scm);

out: