From: Sean Christopherson Date: Fri, 28 Dec 2018 08:33:28 +0000 (-0800) Subject: mm/mmu_notifier.c: remove mmu_notifier_synchronize() X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=6a90a83f1d1957647581ca48caa1f7cc4fa44f8d;p=openwrt%2Fstaging%2Fblogic.git mm/mmu_notifier.c: remove mmu_notifier_synchronize() Contrary to its name, mmu_notifier_synchronize() does not synchronize the notifier's SRCU instance, but rather waits for RCU callbacks to finish. i.e. it invokes rcu_barrier(). The RCU documentation is quite clear on this matter, explicitly calling out that rcu_barrier() does not imply synchronize_rcu(). As there are no callers of mmu_notifier_synchronize() and it's unclear whether any user of mmu_notifier_call_srcu() will ever want to barrier on their callbacks, simply remove the function. Link: http://lkml.kernel.org/r/20181106134705.14197-1-sean.j.christopherson@intel.com Signed-off-by: Sean Christopherson Reviewed-by: Andrew Morton Cc: Peter Zijlstra Cc: Jérôme Glisse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index 9893a6432adf..913c3c13e36e 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -420,7 +420,6 @@ static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) extern void mmu_notifier_call_srcu(struct rcu_head *rcu, void (*func)(struct rcu_head *rcu)); -extern void mmu_notifier_synchronize(void); #else /* CONFIG_MMU_NOTIFIER */ diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 5119ff846769..755466cd289a 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -35,13 +35,6 @@ void mmu_notifier_call_srcu(struct rcu_head *rcu, } EXPORT_SYMBOL_GPL(mmu_notifier_call_srcu); -void mmu_notifier_synchronize(void) -{ - /* Wait for any running method to finish. */ - srcu_barrier(&srcu); -} -EXPORT_SYMBOL_GPL(mmu_notifier_synchronize); - /* * This function can't run concurrently against mmu_notifier_register * because mm->mm_users > 0 during mmu_notifier_register and exit_mmap