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From: Kuniyuki Iwashima <kuniyu@amazon.com>
To: Martin KaFai Lau <martin.lau@linux.dev>,
	Daniel Borkmann <daniel@iogearbox.net>,
	John Fastabend <john.fastabend@gmail.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: "Eduard Zingerman" <eddyz87@gmail.com>,
	"Song Liu" <song@kernel.org>,
	"Yonghong Song" <yonghong.song@linux.dev>,
	"KP Singh" <kpsingh@kernel.org>,
	"Stanislav Fomichev" <sdf@fomichev.me>,
	"Hao Luo" <haoluo@google.com>, "Jiri Olsa" <jolsa@kernel.org>,
	"Mickaël Salaün" <mic@digikod.net>,
	"Günther Noack" <gnoack@google.com>,
	"Paul Moore" <paul@paul-moore.com>,
	"James Morris" <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	"Stephen Smalley" <stephen.smalley.work@gmail.com>,
	"Ondrej Mosnacek" <omosnace@redhat.com>,
	"Casey Schaufler" <casey@schaufler-ca.com>,
	"Christian Brauner" <brauner@kernel.org>,
	"Kuniyuki Iwashima" <kuniyu@amazon.com>,
	"Kuniyuki Iwashima" <kuni1840@gmail.com>,
	bpf@vger.kernel.org, netdev@vger.kernel.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org
Subject: [PATCH v1 bpf-next 3/5] af_unix: Remove redundant scm->fp check in __scm_destroy().
Date: Mon, 5 May 2025 14:56:48 -0700	[thread overview]
Message-ID: <20250505215802.48449-4-kuniyu@amazon.com> (raw)
In-Reply-To: <20250505215802.48449-1-kuniyu@amazon.com>

__scm_destroy() is called from __scm_recv_common() or
scm_destroy(), and both of which check if scm->fp is NULL.

Let's remove the redundant scm->fp check in __scm_destroy().

While at it, we remove EXPORT_SYMBOL() for it and rename it
to scm_fp_destroy() to make the following patch clearer.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 include/net/scm.h |  5 +++--
 net/compat.c      |  2 +-
 net/core/scm.c    | 19 +++++++++----------
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/include/net/scm.h b/include/net/scm.h
index 22bb49589fde..058688a16a63 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -53,7 +53,7 @@ struct scm_cookie {
 void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
 void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
 int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
-void __scm_destroy(struct scm_cookie *scm);
+void scm_fp_destroy(struct scm_cookie *scm);
 struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl);
 
 #ifdef CONFIG_SECURITY_NETWORK
@@ -84,8 +84,9 @@ static __inline__ void scm_destroy_cred(struct scm_cookie *scm)
 static __inline__ void scm_destroy(struct scm_cookie *scm)
 {
 	scm_destroy_cred(scm);
+
 	if (scm->fp)
-		__scm_destroy(scm);
+		scm_fp_destroy(scm);
 }
 
 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
diff --git a/net/compat.c b/net/compat.c
index 485db8ee9b28..6689a4f37bcf 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -326,7 +326,7 @@ void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm)
 	 * All of the files that fit in the message have had their usage counts
 	 * incremented, so we just free the list.
 	 */
-	__scm_destroy(scm);
+	scm_fp_destroy(scm);
 }
 
 /* Argument list sizes for compat_sys_socketcall */
diff --git a/net/core/scm.c b/net/core/scm.c
index 733c0cbd393d..bef8d008f910 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -130,20 +130,19 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
 	return num;
 }
 
-void __scm_destroy(struct scm_cookie *scm)
+void scm_fp_destroy(struct scm_cookie *scm)
 {
 	struct scm_fp_list *fpl = scm->fp;
 	int i;
 
-	if (fpl) {
-		scm->fp = NULL;
-		for (i=fpl->count-1; i>=0; i--)
-			fput(fpl->fp[i]);
-		free_uid(fpl->user);
-		kfree(fpl);
-	}
+	scm->fp = NULL;
+
+	for (i = fpl->count - 1; i >= 0; i--)
+		fput(fpl->fp[i]);
+
+	free_uid(fpl->user);
+	kfree(fpl);
 }
-EXPORT_SYMBOL(__scm_destroy);
 
 int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
 {
@@ -375,7 +374,7 @@ void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
 	 * All of the files that fit in the message have had their usage counts
 	 * incremented, so we just free the list.
 	 */
-	__scm_destroy(scm);
+	scm_fp_destroy(scm);
 }
 EXPORT_SYMBOL(scm_detach_fds);
 
-- 
2.49.0


  parent reply	other threads:[~2025-05-05 21:59 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-05 21:56 [PATCH v1 bpf-next 0/5] af_unix: Allow BPF LSM to scrub SCM_RIGHTS at sendmsg() Kuniyuki Iwashima
2025-05-05 21:56 ` [PATCH v1 bpf-next 1/5] af_unix: Call security_unix_may_send() in sendmsg() for all socket types Kuniyuki Iwashima
2025-05-05 21:56 ` [PATCH v1 bpf-next 2/5] af_unix: Pass skb to security_unix_may_send() Kuniyuki Iwashima
2025-05-05 21:56 ` Kuniyuki Iwashima [this message]
2025-05-09 14:13   ` [PATCH v1 bpf-next 3/5] af_unix: Remove redundant scm->fp check in __scm_destroy() kernel test robot
2025-05-05 21:56 ` [PATCH v1 bpf-next 4/5] bpf: Add kfunc to scrub SCM_RIGHTS at security_unix_may_send() Kuniyuki Iwashima
2025-05-06  0:13   ` Alexei Starovoitov
2025-05-06  8:25     ` Mickaël Salaün
2025-05-09 15:06   ` kernel test robot
2025-05-05 21:56 ` [PATCH v1 bpf-next 5/5] selftest: bpf: Add test for bpf_unix_scrub_fds() Kuniyuki Iwashima
2025-05-05 22:49 ` [PATCH v1 bpf-next 0/5] af_unix: Allow BPF LSM to scrub SCM_RIGHTS at sendmsg() Kumar Kartikeya Dwivedi
2025-05-06  0:21   ` Kuniyuki Iwashima
2025-05-06 16:25     ` Kumar Kartikeya Dwivedi
2025-05-06 18:16       ` Kuniyuki Iwashima
2025-05-06  9:15   ` Christian Brauner
2025-05-06 16:08     ` Kumar Kartikeya Dwivedi
2025-05-06 18:14       ` Kuniyuki Iwashima
2025-05-05 23:21 ` Paul Moore
2025-05-06  0:35   ` Kuniyuki Iwashima
2025-05-06 14:57     ` Paul Moore
2025-05-06 12:17 ` Lennart Poettering
2025-05-06 18:19   ` Kuniyuki Iwashima

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