linux-kselftest.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Christian Brauner <christian.brauner@ubuntu.com>
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 <christian.brauner@ubuntu.com>
Subject: [PATCH v2 5/5] pid: use task_alive() in pidfd_open()
Date: Wed, 16 Oct 2019 17:36:06 +0200	[thread overview]
Message-ID: <20191016153606.2326-5-christian.brauner@ubuntu.com> (raw)
In-Reply-To: <20191016153606.2326-1-christian.brauner@ubuntu.com>

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


  parent reply	other threads:[~2019-10-16 15:37 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-15 14:13 [PATCH 1/2] pidfd: verify task is alive when printing fdinfo Christian Brauner
2019-10-15 14:13 ` [PATCH 2/2] test: verify fdinfo for pidfd of reaped process Christian Brauner
2019-10-16 12:07   ` Christian Kellner
2019-10-15 14:43 ` [PATCH 1/2] pidfd: verify task is alive when printing fdinfo Oleg Nesterov
2019-10-15 14:56   ` Christian Brauner
2019-10-15 15:43     ` Oleg Nesterov
2019-10-16 15:36 ` [PATCH v2 1/5] " Christian Brauner
2019-10-16 15:36   ` [PATCH v2 2/5] test: verify fdinfo for pidfd of reaped process Christian Brauner
2019-10-16 15:36   ` [PATCH v2 3/5] pid: use task_alive() in __change_pid() Christian Brauner
2019-10-16 15:36   ` [PATCH v2 4/5] exit: use task_alive() in do_wait() Christian Brauner
2019-10-16 15:36   ` Christian Brauner [this message]
2019-10-16 16:24   ` [PATCH v2 1/5] pidfd: verify task is alive when printing fdinfo Oleg Nesterov
2019-10-16 16:31     ` Christian Brauner
2019-10-17  8:54       ` Oleg Nesterov
2019-10-17 10:18   ` [PATCH v3 1/5] pidfd: check pid has attached task in fdinfo Christian Brauner
2019-10-17 10:18     ` [PATCH v3 2/5] test: verify fdinfo for pidfd of reaped process Christian Brauner
2019-10-17 10:18     ` [PATCH v3 3/5] pid: use pid_has_task() in __change_pid() Christian Brauner
2019-10-17 10:18     ` [PATCH v3 4/5] exit: use pid_has_task() in do_wait() Christian Brauner
2019-10-17 10:18     ` [PATCH v3 5/5] pid: use pid_has_task() in pidfd_open() Christian Brauner
2019-10-18 15:05     ` [PATCH v3 1/5] pidfd: check pid has attached task in fdinfo Christian Brauner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191016153606.2326-5-christian.brauner@ubuntu.com \
    --to=christian.brauner@ubuntu.com \
    --cc=aarcange@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=christian@kellner.me \
    --cc=cyphar@cyphar.com \
    --cc=elena.reshetova@intel.com \
    --cc=guro@fb.com \
    --cc=jannh@google.com \
    --cc=ldv@altlinux.org \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=mhocko@suse.com \
    --cc=mingo@kernel.org \
    --cc=oleg@redhat.com \
    --cc=peterz@infradead.org \
    --cc=shuah@kernel.org \
    --cc=tglx@linutronix.de \
    --cc=viro@zeniv.linux.org.uk \
    --subject='Re: [PATCH v2 5/5] pid: use task_alive() in pidfd_open()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).