From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file

---
 kernel/net/unix/af_unix.c |   35 +++++++++++++++++++----------------
 1 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/kernel/net/unix/af_unix.c b/kernel/net/unix/af_unix.c
index 2aa01af..440ab64 100644
--- a/kernel/net/unix/af_unix.c
+++ b/kernel/net/unix/af_unix.c
@@ -529,7 +529,7 @@
 	/* Clear state */
 	unix_state_lock(sk);
 	sock_orphan(sk);
-	sk->sk_shutdown = SHUTDOWN_MASK;
+	WRITE_ONCE(sk->sk_shutdown, SHUTDOWN_MASK);
 	path	     = u->path;
 	u->path.dentry = NULL;
 	u->path.mnt = NULL;
@@ -547,7 +547,7 @@
 		if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
 			unix_state_lock(skpair);
 			/* No more writes */
-			skpair->sk_shutdown = SHUTDOWN_MASK;
+			WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK);
 			if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
 				skpair->sk_err = ECONNRESET;
 			unix_state_unlock(skpair);
@@ -587,7 +587,7 @@
 	 *	  What the above comment does talk about? --ANK(980817)
 	 */
 
-	if (unix_tot_inflight)
+	if (READ_ONCE(unix_tot_inflight))
 		unix_gc();		/* Garbage collect fds */
 }
 
@@ -697,7 +697,7 @@
 	if (mutex_lock_interruptible(&u->iolock))
 		return -EINTR;
 
-	sk->sk_peek_off = val;
+	WRITE_ONCE(sk->sk_peek_off, val);
 	mutex_unlock(&u->iolock);
 
 	return 0;
@@ -1236,7 +1236,7 @@
 
 	sched = !sock_flag(other, SOCK_DEAD) &&
 		!(other->sk_shutdown & RCV_SHUTDOWN) &&
-		unix_recvq_full(other);
+		unix_recvq_full_lockless(other);
 
 	unix_state_unlock(other);
 
@@ -2008,6 +2008,7 @@
 
 	if (false) {
 alloc_skb:
+		spin_unlock(&other->sk_receive_queue.lock);
 		unix_state_unlock(other);
 		mutex_unlock(&unix_sk(other)->iolock);
 		newskb = sock_alloc_send_pskb(sk, 0, 0, flags & MSG_DONTWAIT,
@@ -2047,6 +2048,7 @@
 		init_scm = false;
 	}
 
+	spin_lock(&other->sk_receive_queue.lock);
 	skb = skb_peek_tail(&other->sk_receive_queue);
 	if (tail && tail == skb) {
 		skb = newskb;
@@ -2077,14 +2079,11 @@
 	refcount_add(size, &sk->sk_wmem_alloc);
 
 	if (newskb) {
-		err = unix_scm_to_skb(&scm, skb, false);
-		if (err)
-			goto err_state_unlock;
-		spin_lock(&other->sk_receive_queue.lock);
+		unix_scm_to_skb(&scm, skb, false);
 		__skb_queue_tail(&other->sk_receive_queue, newskb);
-		spin_unlock(&other->sk_receive_queue.lock);
 	}
 
+	spin_unlock(&other->sk_receive_queue.lock);
 	unix_state_unlock(other);
 	mutex_unlock(&unix_sk(other)->iolock);
 
@@ -2581,7 +2580,7 @@
 	++mode;
 
 	unix_state_lock(sk);
-	sk->sk_shutdown |= mode;
+	WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | mode);
 	other = unix_peer(sk);
 	if (other)
 		sock_hold(other);
@@ -2598,7 +2597,7 @@
 		if (mode&SEND_SHUTDOWN)
 			peer_mode |= RCV_SHUTDOWN;
 		unix_state_lock(other);
-		other->sk_shutdown |= peer_mode;
+		WRITE_ONCE(other->sk_shutdown, other->sk_shutdown | peer_mode);
 		unix_state_unlock(other);
 		other->sk_state_change(other);
 		if (peer_mode == SHUTDOWN_MASK)
@@ -2717,16 +2716,18 @@
 {
 	struct sock *sk = sock->sk;
 	__poll_t mask;
+	u8 shutdown;
 
 	sock_poll_wait(file, sock, wait);
 	mask = 0;
+	shutdown = READ_ONCE(sk->sk_shutdown);
 
 	/* exceptional events? */
 	if (sk->sk_err)
 		mask |= EPOLLERR;
-	if (sk->sk_shutdown == SHUTDOWN_MASK)
+	if (shutdown == SHUTDOWN_MASK)
 		mask |= EPOLLHUP;
-	if (sk->sk_shutdown & RCV_SHUTDOWN)
+	if (shutdown & RCV_SHUTDOWN)
 		mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
 
 	/* readable? */
@@ -2754,18 +2755,20 @@
 	struct sock *sk = sock->sk, *other;
 	unsigned int writable;
 	__poll_t mask;
+	u8 shutdown;
 
 	sock_poll_wait(file, sock, wait);
 	mask = 0;
+	shutdown = READ_ONCE(sk->sk_shutdown);
 
 	/* exceptional events? */
 	if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
 		mask |= EPOLLERR |
 			(sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);
 
-	if (sk->sk_shutdown & RCV_SHUTDOWN)
+	if (shutdown & RCV_SHUTDOWN)
 		mask |= EPOLLRDHUP | EPOLLIN | EPOLLRDNORM;
-	if (sk->sk_shutdown == SHUTDOWN_MASK)
+	if (shutdown == SHUTDOWN_MASK)
 		mask |= EPOLLHUP;
 
 	/* readable? */

--
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