From f1f1007644ffc8051a4c11427d58b1967ae7b75a Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Mon, 27 Feb 2017 14:30:07 -0800 Subject: mm: add new mmgrab() helper Apart from adding the helper function itself, the rest of the kernel is converted mechanically using: git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/' git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/' This is needed for a later patch that hooks into the helper, but might be a worthwhile cleanup on its own. (Michal Hocko provided most of the kerneldoc comment.) Link: http://lkml.kernel.org/r/20161218123229.22952-1-vegard.nossum@oracle.com Signed-off-by: Vegard Nossum Acked-by: Michal Hocko Acked-by: Peter Zijlstra (Intel) Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 2 +- kernel/futex.c | 2 +- kernel/sched/core.c | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/exit.c b/kernel/exit.c index 90b09ca35c84..8a768a3672a5 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -539,7 +539,7 @@ static void exit_mm(void) __set_current_state(TASK_RUNNING); down_read(&mm->mmap_sem); } - atomic_inc(&mm->mm_count); + mmgrab(mm); BUG_ON(mm != current->active_mm); /* more a memory barrier than a real lock */ task_lock(current); diff --git a/kernel/futex.c b/kernel/futex.c index cdf365036141..b687cb22301c 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -338,7 +338,7 @@ static inline bool should_fail_futex(bool fshared) static inline void futex_get_mm(union futex_key *key) { - atomic_inc(&key->private.mm->mm_count); + mmgrab(key->private.mm); /* * Ensure futex_get_mm() implies a full barrier such that * get_futex_key() implies a full barrier. This is relied upon diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e1ae6ac15eac..6ea1925ac5c0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2847,7 +2847,7 @@ context_switch(struct rq *rq, struct task_struct *prev, if (!mm) { next->active_mm = oldmm; - atomic_inc(&oldmm->mm_count); + mmgrab(oldmm); enter_lazy_tlb(oldmm, next); } else switch_mm_irqs_off(oldmm, mm, next); @@ -6098,7 +6098,7 @@ void __init sched_init(void) /* * The boot idle thread does lazy MMU switching as well: */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); enter_lazy_tlb(&init_mm, current); /* -- cgit v1.2.3