From:   Leo Yan <leo.yan@linaro.org>
To:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Mike Leach <mike.leach@linaro.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jan Harkes <jaharkes@cs.cmu.edu>, coda@cs.cmu.edu,
        Paul Moore <paul@paul-moore.com>,
        Eric Paris <eparis@redhat.com>,
        Balbir Singh <bsingharora@gmail.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, coresight@lists.linaro.org,
        linux-arm-kernel@lists.infradead.org, codalist@coda.cs.cmu.edu,
        linux-audit@redhat.com
Cc:     Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v1 1/7] pid: Introduce helper task_is_in_root_ns()
Date:   Sun,  5 Dec 2021 22:50:59 +0800
Message-Id: <20211205145105.57824-2-leo.yan@linaro.org>
In-Reply-To: <20211205145105.57824-1-leo.yan@linaro.org>
References: <20211205145105.57824-1-leo.yan@linaro.org>
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Currently the kernel uses open code in multiple places to check if a
task is in the root PID namespace with the kind of format:

  if (task_active_pid_ns(current) == &init_pid_ns)
      do_something();

This patch creates a new helper function, task_is_in_root_ns(), it
returns true if a passed task is in the root PID namespace, otherwise
returns false.  So it will be used to replace open codes.

Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 include/linux/pid_namespace.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 7c7e627503d2..bf82b373f022 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -86,4 +86,9 @@ extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);
 void pidhash_init(void);
 void pid_idr_init(void);
 
+static inline bool task_is_in_root_ns(struct task_struct *tsk)
+{
+	return task_active_pid_ns(tsk) == &init_pid_ns;
+}
+
 #endif /* _LINUX_PID_NS_H */
-- 
2.25.1