Re: [PATCH] files: rcu free files_struct

[Linus Torvalds]

On Wed, Dec 9, 2020 at 2:58 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, Dec 09, 2020 at 07:49:38PM +0000, Matthew Wilcox wrote:
> >
> > Assuming this is safe, you can use RCU_INIT_POINTER() here because you're
> > storing NULL, so you don't need the wmb() before storing the pointer.
>
> fs/file.c:pick_file() would make more interesting target for the same treatment...

Actually, don't.

rcu_assign_pointer() itself already does the optimization for the case
of a constant NULL pointer assignment.

So there's no need to manually change things to RCU_INIT_POINTER().

           Linus