Revert "mm, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacks"

Revert 5ff7091f5a2ca ("mm, mmu_notifier: annotate mmu notifiers with
blockable invalidate callbacks").

MMU_INVALIDATE_DOES_NOT_BLOCK flags was the only one used and it is no
longer needed since 93065ac753e4 ("mm, oom: distinguish blockable mode for
mmu notifiers").  We now have a full support for per range !blocking
behavior so we can drop the stop gap workaround which the per notifier
flag was used for.

Link: http://lkml.kernel.org/r/20180827112623.8992-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 31 deletions

diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 82bb1a939c0e..5119ff846769 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -247,37 +247,6 @@ void __mmu_notifier_invalidate_range(struct mm_struct *mm,
 }
 EXPORT_SYMBOL_GPL(__mmu_notifier_invalidate_range);
 
-/*
- * Must be called while holding mm->mmap_sem for either read or write.
- * The result is guaranteed to be valid until mm->mmap_sem is dropped.
- */
-bool mm_has_blockable_invalidate_notifiers(struct mm_struct *mm)
-{
-	struct mmu_notifier *mn;
-	int id;
-	bool ret = false;
-
-	WARN_ON_ONCE(!rwsem_is_locked(&mm->mmap_sem));
-
-	if (!mm_has_notifiers(mm))
-		return ret;
-
-	id = srcu_read_lock(&srcu);
-	hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
-		if (!mn->ops->invalidate_range &&
-		    !mn->ops->invalidate_range_start &&
-		    !mn->ops->invalidate_range_end)
-				continue;
-
-		if (!(mn->ops->flags & MMU_INVALIDATE_DOES_NOT_BLOCK)) {
-			ret = true;
-			break;
-		}
-	}
-	srcu_read_unlock(&srcu, id);
-	return ret;
-}
-
 static int do_mmu_notifier_register(struct mmu_notifier *mn,
 				    struct mm_struct *mm,
 				    int take_mmap_sem)