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 oleg@redhat.com Signed-off-by: Christian Brauner christian.brauner@ubuntu.com --- /* 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; }