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From:   Leo Yan <leo.yan@linaro.org>
To:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Leon Romanovsky <leon@kernel.org>,
        Balbir Singh <bsingharora@gmail.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Leo Yan <leo.yan@linaro.org>, Leon Romanovsky <leonro@nvidia.com>
Subject: [PATCH net v3 1/2] pid: Introduce helper task_is_in_init_pid_ns()
Date:   Wed, 26 Jan 2022 13:04:26 +0800
Message-Id: <20220126050427.605628-2-leo.yan@linaro.org>
In-Reply-To: <20220126050427.605628-1-leo.yan@linaro.org>
References: <20220126050427.605628-1-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_init_pid_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>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
---
 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..07481bb87d4e 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_init_pid_ns(struct task_struct *tsk)
+{
+	return task_active_pid_ns(tsk) == &init_pid_ns;
+}
+
 #endif /* _LINUX_PID_NS_H */
-- 
2.25.1