5.4-stable review patch. If anyone has any objections, please let me know.
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From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit 97af84a6bba2ab2b9c704c08e67de3b5ea551bb2 ]
When touching unix_sk(sk)->inflight, we are always under spin_lock(&unix_gc_lock).
Let's convert unix_sk(sk)->inflight to the normal unsigned long.
Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Reviewed-by: Simon Horman horms@kernel.org Link: https://lore.kernel.org/r/20240123170856.41348-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski kuba@kernel.org Stable-dep-of: 47d8ac011fe1 ("af_unix: Fix garbage collector racing against connect()") Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/af_unix.h | 2 +- net/unix/af_unix.c | 4 ++-- net/unix/garbage.c | 17 ++++++++--------- net/unix/scm.c | 8 +++++--- 4 files changed, 16 insertions(+), 15 deletions(-)
diff --git a/include/net/af_unix.h b/include/net/af_unix.h index 6cb5026cf7272..e7612295b2626 100644 --- a/include/net/af_unix.h +++ b/include/net/af_unix.h @@ -52,7 +52,7 @@ struct unix_sock { struct mutex iolock, bindlock; struct sock *peer; struct list_head link; - atomic_long_t inflight; + unsigned long inflight; spinlock_t lock; unsigned long gc_flags; #define UNIX_GC_CANDIDATE 0 diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 9b1dd845bca19..53335989a6f0c 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -809,11 +809,11 @@ static struct sock *unix_create1(struct net *net, struct socket *sock, int kern) sk->sk_write_space = unix_write_space; sk->sk_max_ack_backlog = net->unx.sysctl_max_dgram_qlen; sk->sk_destruct = unix_sock_destructor; - u = unix_sk(sk); + u = unix_sk(sk); + u->inflight = 0; u->path.dentry = NULL; u->path.mnt = NULL; spin_lock_init(&u->lock); - atomic_long_set(&u->inflight, 0); INIT_LIST_HEAD(&u->link); mutex_init(&u->iolock); /* single task reading lock */ mutex_init(&u->bindlock); /* single task binding lock */ diff --git a/net/unix/garbage.c b/net/unix/garbage.c index 9121a4d5436d5..675fbe594dbb3 100644 --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -166,17 +166,18 @@ static void scan_children(struct sock *x, void (*func)(struct unix_sock *),
static void dec_inflight(struct unix_sock *usk) { - atomic_long_dec(&usk->inflight); + usk->inflight--; }
static void inc_inflight(struct unix_sock *usk) { - atomic_long_inc(&usk->inflight); + usk->inflight++; }
static void inc_inflight_move_tail(struct unix_sock *u) { - atomic_long_inc(&u->inflight); + u->inflight++; + /* If this still might be part of a cycle, move it to the end * of the list, so that it's checked even if it was already * passed over @@ -237,14 +238,12 @@ void unix_gc(void) */ list_for_each_entry_safe(u, next, &gc_inflight_list, link) { long total_refs; - long inflight_refs;
total_refs = file_count(u->sk.sk_socket->file); - inflight_refs = atomic_long_read(&u->inflight);
- BUG_ON(inflight_refs < 1); - BUG_ON(total_refs < inflight_refs); - if (total_refs == inflight_refs) { + BUG_ON(!u->inflight); + BUG_ON(total_refs < u->inflight); + if (total_refs == u->inflight) { list_move_tail(&u->link, &gc_candidates); __set_bit(UNIX_GC_CANDIDATE, &u->gc_flags); __set_bit(UNIX_GC_MAYBE_CYCLE, &u->gc_flags); @@ -271,7 +270,7 @@ void unix_gc(void) /* Move cursor to after the current position. */ list_move(&cursor, &u->link);
- if (atomic_long_read(&u->inflight) > 0) { + if (u->inflight) { list_move_tail(&u->link, ¬_cycle_list); __clear_bit(UNIX_GC_MAYBE_CYCLE, &u->gc_flags); scan_children(&u->sk, inc_inflight_move_tail, NULL); diff --git a/net/unix/scm.c b/net/unix/scm.c index 51b623de3be5f..785e8c4669e23 100644 --- a/net/unix/scm.c +++ b/net/unix/scm.c @@ -51,12 +51,13 @@ void unix_inflight(struct user_struct *user, struct file *fp) if (s) { struct unix_sock *u = unix_sk(s);
- if (atomic_long_inc_return(&u->inflight) == 1) { + if (!u->inflight) { BUG_ON(!list_empty(&u->link)); list_add_tail(&u->link, &gc_inflight_list); } else { BUG_ON(list_empty(&u->link)); } + u->inflight++; /* Paired with READ_ONCE() in wait_for_unix_gc() */ WRITE_ONCE(unix_tot_inflight, unix_tot_inflight + 1); } @@ -73,10 +74,11 @@ void unix_notinflight(struct user_struct *user, struct file *fp) if (s) { struct unix_sock *u = unix_sk(s);
- BUG_ON(!atomic_long_read(&u->inflight)); + BUG_ON(!u->inflight); BUG_ON(list_empty(&u->link));
- if (atomic_long_dec_and_test(&u->inflight)) + u->inflight--; + if (!u->inflight) list_del_init(&u->link); /* Paired with READ_ONCE() in wait_for_unix_gc() */ WRITE_ONCE(unix_tot_inflight, unix_tot_inflight - 1);