From mboxrd@z Thu Jan 1 00:00:00 1970 From: 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> References: <20191015141332.4055-1-christian.brauner@ubuntu.com> <20191016153606.2326-1-christian.brauner@ubuntu.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20191016153606.2326-1-christian.brauner@ubuntu.com> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-api@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; } -- 2.23.0