The in_vfork() function deals with task->mm, so it better belongs into <linux/sched/mm.h>.
Cc: Peter Zijlstra <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: [email protected] Signed-off-by: Ingo Molnar <[email protected]> --- include/linux/sched.h | 26 -------------------------- include/linux/sched/mm.h | 27 +++++++++++++++++++++++++++ 2 files changed, 27 insertions(+), 26 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 90093b656b46..f7aea422b9cf 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1245,32 +1245,6 @@ static inline int tsk_nr_cpus_allowed(struct task_struct *p) #define TNF_FAULT_LOCAL 0x08 #define TNF_MIGRATE_FAIL 0x10 -static inline bool in_vfork(struct task_struct *tsk) -{ - bool ret; - - /* - * need RCU to access ->real_parent if CLONE_VM was used along with - * CLONE_PARENT. - * - * We check real_parent->mm == tsk->mm because CLONE_VFORK does not - * imply CLONE_VM - * - * CLONE_VFORK can be used with CLONE_PARENT/CLONE_THREAD and thus - * ->real_parent is not necessarily the task doing vfork(), so in - * theory we can't rely on task_lock() if we want to dereference it. - * - * And in this case we can't trust the real_parent->mm == tsk->mm - * check, it can be false negative. But we do not care, if init or - * another oom-unkillable task does this it should blame itself. - */ - rcu_read_lock(); - ret = tsk->vfork_done && tsk->real_parent->mm == tsk->mm; - rcu_read_unlock(); - - return ret; -} - #ifdef CONFIG_NUMA_BALANCING extern void task_numa_fault(int last_node, int node, int pages, int flags); extern pid_t task_numa_group_id(struct task_struct *p); diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 0aff84e1098a..6eb9677b88bf 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -3,6 +3,7 @@ #include <linux/kernel.h> #include <linux/atomic.h> +#include <linux/sched.h> /* * Routines for handling mm_structs @@ -77,4 +78,30 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, static inline void arch_pick_mmap_layout(struct mm_struct *mm) {} #endif +static inline bool in_vfork(struct task_struct *tsk) +{ + bool ret; + + /* + * need RCU to access ->real_parent if CLONE_VM was used along with + * CLONE_PARENT. + * + * We check real_parent->mm == tsk->mm because CLONE_VFORK does not + * imply CLONE_VM + * + * CLONE_VFORK can be used with CLONE_PARENT/CLONE_THREAD and thus + * ->real_parent is not necessarily the task doing vfork(), so in + * theory we can't rely on task_lock() if we want to dereference it. + * + * And in this case we can't trust the real_parent->mm == tsk->mm + * check, it can be false negative. But we do not care, if init or + * another oom-unkillable task does this it should blame itself. + */ + rcu_read_lock(); + ret = tsk->vfork_done && tsk->real_parent->mm == tsk->mm; + rcu_read_unlock(); + + return ret; +} + #endif /* _LINUX_SCHED_MM_H */ -- 2.7.4
