From d7e4f8545b497b3f5687e592f1c355cbaee64c8c Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Wed, 26 Jan 2022 13:04:26 +0800 Subject: [PATCH 1/2] 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 Signed-off-by: Leo Yan Reviewed-by: Leon Romanovsky Acked-by: Suzuki K Poulose Acked-by: Balbir Singh Signed-off-by: Jakub Kicinski --- 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 */ From 42c66d16756402c4749d94f005a998a43e8fa338 Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Wed, 26 Jan 2022 13:04:27 +0800 Subject: [PATCH 2/2] connector/cn_proc: Use task_is_in_init_pid_ns() This patch replaces open code with task_is_in_init_pid_ns() to check if a task is in root PID namespace. Signed-off-by: Leo Yan Acked-by: Balbir Singh Signed-off-by: Jakub Kicinski --- drivers/connector/cn_proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c index 646ad385e490..ccac1c453080 100644 --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -358,7 +358,7 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg, * other namespaces. */ if ((current_user_ns() != &init_user_ns) || - (task_active_pid_ns(current) != &init_pid_ns)) + !task_is_in_init_pid_ns(current)) return; /* Can only change if privileged. */