From 5cd204550b1a006f2b0c986b0e0f53220ebfd391 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Wed, 30 Apr 2008 00:54:24 -0700 Subject: [PATCH] Deprecate find_task_by_pid() There are some places that are known to operate on tasks' global pids only: * the rest_init() call (called on boot) * the kgdb's getthread * the create_kthread() (since the kthread is run in init ns) So use the find_task_by_pid_ns(..., &init_pid_ns) there and schedule the find_task_by_pid for removal. [sukadev@us.ibm.com: Fix warning in kernel/pid.c] Signed-off-by: Pavel Emelyanov Cc: "Eric W. Biederman" Signed-off-by: Sukadev Bhattiprolu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/feature-removal-schedule.txt | 18 ++++++++++++++++++ include/linux/sched.h | 5 ++++- init/main.c | 2 +- kernel/kthread.c | 2 +- kernel/pid.c | 6 ------ 5 files changed, 24 insertions(+), 9 deletions(-) diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 599fe55..3c35d45 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -138,6 +138,24 @@ Who: Kay Sievers --------------------------- +What: find_task_by_pid +When: 2.6.26 +Why: With pid namespaces, calling this funciton will return the + wrong task when called from inside a namespace. + + The best way to save a task pid and find a task by this + pid later, is to find this task's struct pid pointer (or get + it directly from the task) and call pid_task() later. + + If someone really needs to get a task by its pid_t, then + he most likely needs the find_task_by_vpid() to get the + task from the same namespace as the current task is in, but + this may be not so in general. + +Who: Pavel Emelyanov + +--------------------------- + What: ACPI procfs interface When: July 2008 Why: ACPI sysfs conversion should be finished by January 2008. diff --git a/include/linux/sched.h b/include/linux/sched.h index 86e6079..03c2380 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1677,7 +1677,10 @@ extern struct pid_namespace init_pid_ns; extern struct task_struct *find_task_by_pid_type_ns(int type, int pid, struct pid_namespace *ns); -extern struct task_struct *find_task_by_pid(pid_t nr); +static inline struct task_struct *__deprecated find_task_by_pid(pid_t nr) +{ + return find_task_by_pid_type_ns(PIDTYPE_PID, nr, &init_pid_ns); +} extern struct task_struct *find_task_by_vpid(pid_t nr); extern struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns); diff --git a/init/main.c b/init/main.c index 1f44064..dff253c 100644 --- a/init/main.c +++ b/init/main.c @@ -459,7 +459,7 @@ static void noinline __init_refok rest_init(void) kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); numa_default_policy(); pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); - kthreadd_task = find_task_by_pid(pid); + kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); unlock_kernel(); /* diff --git a/kernel/kthread.c b/kernel/kthread.c index ac72eea..bd1b9ea 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -98,7 +98,7 @@ static void create_kthread(struct kthread_create_info *create) struct sched_param param = { .sched_priority = 0 }; wait_for_completion(&create->started); read_lock(&tasklist_lock); - create->result = find_task_by_pid(pid); + create->result = find_task_by_pid_ns(pid, &init_pid_ns); read_unlock(&tasklist_lock); /* * root may have changed our (kthreadd's) priority or CPU mask. diff --git a/kernel/pid.c b/kernel/pid.c index b322cdf..a9ae9f7 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -381,12 +381,6 @@ struct task_struct *find_task_by_pid_type_ns(int type, int nr, EXPORT_SYMBOL(find_task_by_pid_type_ns); -struct task_struct *find_task_by_pid(pid_t nr) -{ - return find_task_by_pid_type_ns(PIDTYPE_PID, nr, &init_pid_ns); -} -EXPORT_SYMBOL(find_task_by_pid); - struct task_struct *find_task_by_vpid(pid_t vnr) { return find_task_by_pid_type_ns(PIDTYPE_PID, vnr, -- 2.7.4