pid: Introduce helper task_is_in_init_pid_ns()

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>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 7c7e627503d228aef991a71b86d434b0900a6033..07481bb87d4e0c40a8e6f0b289e6d30486d2b75b 100644 (file)
--- 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 */