diff mbox series

[v3,net-next,09/11] af_unix: Set sk_peer_pid/sk_peer_cred locklessly for new socket.

Message ID 20240614200715.93150-10-kuniyu@amazon.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series af_unix: Remove spin_lock_nested() and convert to lock_cmp_fn. | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 851 this patch: 851
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 849 this patch: 849
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 855 this patch: 855
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 29 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-06-16--18-00 (tests: 659)

Commit Message

Kuniyuki Iwashima June 14, 2024, 8:07 p.m. UTC 
init_peercred() is called in 3 places:

  1. socketpair() : both sockets
  2. connect()    : child socket
  3. listen()     : listening socket

The first two need not hold sk_peer_lock because no one can
touch the socket.

Let's set cred/pid without holding lock for the two cases and
rename the old init_peercred() to update_peercred() to properly
reflect the use case.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/unix/af_unix.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 9bbd112926ad..3c62fb4f3df5 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -738,6 +738,12 @@  static void unix_release_sock(struct sock *sk, int embrion)
 }
 
 static void init_peercred(struct sock *sk)
+{
+	sk->sk_peer_pid = get_pid(task_tgid(current));
+	sk->sk_peer_cred = get_current_cred();
+}
+
+static void update_peercred(struct sock *sk)
 {
 	const struct cred *old_cred;
 	struct pid *old_pid;
@@ -745,8 +751,7 @@  static void init_peercred(struct sock *sk)
 	spin_lock(&sk->sk_peer_lock);
 	old_pid = sk->sk_peer_pid;
 	old_cred = sk->sk_peer_cred;
-	sk->sk_peer_pid  = get_pid(task_tgid(current));
-	sk->sk_peer_cred = get_current_cred();
+	init_peercred(sk);
 	spin_unlock(&sk->sk_peer_lock);
 
 	put_pid(old_pid);
@@ -798,7 +803,7 @@  static int unix_listen(struct socket *sock, int backlog)
 	WRITE_ONCE(sk->sk_state, TCP_LISTEN);
 
 	/* set credentials so connect can copy them */
-	init_peercred(sk);
+	update_peercred(sk);
 	err = 0;
 
 out_unlock: