From patchwork Wed Oct 16 15:36:06 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 11193637 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6E0C81390 for ; Wed, 16 Oct 2019 15:37:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59C9521A49 for ; Wed, 16 Oct 2019 15:37:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405279AbfJPPhV (ORCPT ); Wed, 16 Oct 2019 11:37:21 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:47481 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405140AbfJPPhU (ORCPT ); Wed, 16 Oct 2019 11:37:20 -0400 Received: from [213.220.153.21] (helo=localhost.localdomain) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1iKlMU-00050w-QB; Wed, 16 Oct 2019 15:37:18 +0000 From: Christian Brauner To: oleg@redhat.com, linux-kernel@vger.kernel.org Cc: aarcange@redhat.com, akpm@linux-foundation.org, christian@kellner.me, cyphar@cyphar.com, elena.reshetova@intel.com, guro@fb.com, jannh@google.com, ldv@altlinux.org, linux-api@vger.kernel.org, linux-kselftest@vger.kernel.org, mhocko@suse.com, mingo@kernel.org, peterz@infradead.org, shuah@kernel.org, tglx@linutronix.de, viro@zeniv.linux.org.uk, Christian Brauner Subject: [PATCH v2 5/5] pid: use task_alive() in pidfd_open() Date: Wed, 16 Oct 2019 17:36:06 +0200 Message-Id: <20191016153606.2326-5-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016153606.2326-1-christian.brauner@ubuntu.com> References: <20191015141332.4055-1-christian.brauner@ubuntu.com> <20191016153606.2326-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Use the new task_alive() helper in pidfd_open(). This simplifies the code and avoids taking rcu_read_{lock,unlock}() and leads to overall nicer code. Cc: Oleg Nesterov Signed-off-by: Christian Brauner --- /* v1 */ patch not present /* v2 */ patch introduced --- kernel/pid.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/kernel/pid.c b/kernel/pid.c index 70ad4a9f728c..1f425b6c4c47 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -497,7 +497,7 @@ static int pidfd_create(struct pid *pid) */ SYSCALL_DEFINE2(pidfd_open, pid_t, pid, unsigned int, flags) { - int fd, ret; + int fd; struct pid *p; if (flags) @@ -510,13 +510,11 @@ SYSCALL_DEFINE2(pidfd_open, pid_t, pid, unsigned int, flags) if (!p) return -ESRCH; - ret = 0; - rcu_read_lock(); - if (!pid_task(p, PIDTYPE_TGID)) - ret = -EINVAL; - rcu_read_unlock(); + if (task_alive(p, PIDTYPE_TGID)) + fd = pidfd_create(p); + else + fd = -EINVAL; - fd = ret ?: pidfd_create(p); put_pid(p); return fd; }