1 files changed, 13 insertions, 69 deletions

diff --git a/net/unix/garbage.c b/net/unix/garbage.c
index c36757e72844..4d283e26d816 100644
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -86,77 +86,13 @@
 #include <net/scm.h>
 #include <net/tcp_states.h>
 
+#include "scm.h"
+
 /* Internal data structures and random procedures: */
 
-static LIST_HEAD(gc_inflight_list);
 static LIST_HEAD(gc_candidates);
-static DEFINE_SPINLOCK(unix_gc_lock);
 static DECLARE_WAIT_QUEUE_HEAD(unix_gc_wait);
 
-unsigned int unix_tot_inflight;
-
-struct sock *unix_get_socket(struct file *filp)
-{
-	struct sock *u_sock = NULL;
-	struct inode *inode = file_inode(filp);
-
-	/* Socket ? */
-	if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) {
-		struct socket *sock = SOCKET_I(inode);
-		struct sock *s = sock->sk;
-
-		/* PF_UNIX ? */
-		if (s && sock->ops && sock->ops->family == PF_UNIX)
-			u_sock = s;
-	}
-	return u_sock;
-}
-
-/* Keep the number of times in flight count for the file
- * descriptor if it is for an AF_UNIX socket.
- */
-
-void unix_inflight(struct user_struct *user, struct file *fp)
-{
-	struct sock *s = unix_get_socket(fp);
-
-	spin_lock(&unix_gc_lock);
-
-	if (s) {
-		struct unix_sock *u = unix_sk(s);
-
-		if (atomic_long_inc_return(&u->inflight) == 1) {
-			BUG_ON(!list_empty(&u->link));
-			list_add_tail(&u->link, &gc_inflight_list);
-		} else {
-			BUG_ON(list_empty(&u->link));
-		}
-		unix_tot_inflight++;
-	}
-	user->unix_inflight++;
-	spin_unlock(&unix_gc_lock);
-}
-
-void unix_notinflight(struct user_struct *user, struct file *fp)
-{
-	struct sock *s = unix_get_socket(fp);
-
-	spin_lock(&unix_gc_lock);
-
-	if (s) {
-		struct unix_sock *u = unix_sk(s);
-
-		BUG_ON(!atomic_long_read(&u->inflight));
-		BUG_ON(list_empty(&u->link));
-
-		if (atomic_long_dec_and_test(&u->inflight))
-			list_del_init(&u->link);
-		unix_tot_inflight--;
-	}
-	user->unix_inflight--;
-	spin_unlock(&unix_gc_lock);
-}
-
 static void scan_inflight(struct sock *x, void (*func)(struct unix_sock *),
 			  struct sk_buff_head *hitlist)
 {
@@ -261,8 +197,11 @@ void wait_for_unix_gc(void)
 {
 	/* If number of inflight sockets is insane,
 	 * force a garbage collect right now.
+	 * Paired with the WRITE_ONCE() in unix_inflight(),
+	 * unix_notinflight() and gc_in_progress().
 	 */
-	if (unix_tot_inflight > UNIX_INFLIGHT_TRIGGER_GC && !gc_in_progress)
+	if (READ_ONCE(unix_tot_inflight) > UNIX_INFLIGHT_TRIGGER_GC &&
+	    !READ_ONCE(gc_in_progress))
 		unix_gc();
 	wait_event(unix_gc_wait, gc_in_progress == false);
 }
@@ -282,7 +221,9 @@ void unix_gc(void)
 	if (gc_in_progress)
 		goto out;
 
-	gc_in_progress = true;
+	/* Paired with READ_ONCE() in wait_for_unix_gc(). */
+	WRITE_ONCE(gc_in_progress, true);
+
 	/* First, select candidates for garbage collection.  Only
 	 * in-flight sockets are considered, and from those only ones
 	 * which don't have any external reference.
@@ -368,7 +309,10 @@ void unix_gc(void)
 
 	/* All candidates should have been detached by now. */
 	BUG_ON(!list_empty(&gc_candidates));
-	gc_in_progress = false;
+
+	/* Paired with READ_ONCE() in wait_for_unix_gc(). */
+	WRITE_ONCE(gc_in_progress, false);
+
 	wake_up(&unix_gc_wait);
 
  out: