Re: [PATCH 05/16] overlayfs: Replace smp_read_barrier_depends() with lockless_dereference()

From: Miklos Szeredi
Date: Mon Nov 17 2014 - 05:35:31 EST


On Thu, Nov 13, 2014 at 8:24 PM, Pranith Kumar <bobby.prani@xxxxxxxxx> wrote:
> Recently lockless_dereference() was added which can be used in place of
> hard-coding smp_read_barrier_depends(). The following PATCH makes the change.
>
> Signed-off-by: Pranith Kumar <bobby.prani@xxxxxxxxx>
> ---
> fs/overlayfs/super.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index 08b704c..b0f050e 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -84,12 +84,10 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry)
>
> static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
> {
> - struct dentry *upperdentry = ACCESS_ONCE(oe->__upperdentry);
> /*
> * Make sure to order reads to upperdentry wrt ovl_dentry_update()
> */
> - smp_read_barrier_depends();
> - return upperdentry;
> + return lockless_dereference(oe->__upperdentry);
> }
>
> void ovl_path_upper(struct dentry *dentry, struct path *path)
> --
> 1.9.1
>

Thanks, already in overlayfs-next branch of

git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git overlayfs-next

Thanks,
Miklos
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