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Subject[PATCH v2 5/5] pid: use task_alive() in pidfd_open()
Date
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;
}
--
2.23.0
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