Re: [PATCH] anon_vmas: Convert the rwsem to an rwlock_t

[Ingo Molnar]

* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Sat, Sep 28, 2013 at 12:37 PM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> >
> > -               down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem);
> > +               down_write_nest_lock(&anon_vma->root->rwlock, &mm->mmap_sem);
> 
> That's just completely bogus, and cannot work.

Told you it's totally untested :-) Found that build failure a few minutes 
ago (the place escaped my search pattern), I'm trying the fix below.

	Ingo

diff --git a/mm/mmap.c b/mm/mmap.c
index 25ce233..7ee85bf 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2955,7 +2955,7 @@ static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
 		 * The LSB of head.next can't change from under us
 		 * because we hold the mm_all_locks_mutex.
 		 */
-		down_write_nest_lock(&anon_vma->root->rwlock, &mm->mmap_sem);
+		write_lock(&anon_vma->root->rwlock);
 		/*
 		 * We can safely modify head.next after taking the
 		 * anon_vma->root->rwlock. If some other vma in this mm shares
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/