Re: [RFC 04/10] Temporary struct vfs_lookup in file_permission

Andreas Gruenbacher
2007-08-08T18:57:18Z

On Wednesday 08 August 2007 19:58, Josef Sipek wrote:
> On Wed, Aug 08, 2007 at 07:16:26PM +0200, Andreas Gruenbacher wrote:
> > Create a temporary struct vfs_lookup in file_permission() instead of
> > passing a NULL value.
> >
> > Signed-off-by: Andreas Gruenbacher <ag@bestbits.at>
> >
> > ---
> > fs/namei.c | 11 ++++++-----
> > 1 file changed, 6 insertions(+), 5 deletions(-)
> >
> > --- a/fs/namei.c
> > +++ b/fs/namei.c
> > @@ -292,14 +292,15 @@ int vfs_permission(struct vfs_lookup *lo
> > *
> > * Used to check for read/write/execute permissions on an already opened
> > * file.
> > - *
> > - * Note:
> > - * Do not use this function in new code. All access checks should
> > - * be done using vfs_permission().
>
> Should this comment be removed?

IMO yes. If vfs_permission() works for a piece of code it's the obvious
preference. If on the other hand you really need to check permissions on a
file, then why not use this function?

> > */
> > int file_permission(struct file *file, int mask)
> > {
> > - return permission(file->f_path.dentry->d_inode, mask, NULL);
> > + struct vfs_lookup lookup;
> > +
> > + lookup.path = file->f_path;
> > + lookup.flags = 0;
>
> I tend to find this little bit cleaner:
>
> struct vfs_lookup lookup = {
> .path = file->f_path,
> .flags = 0,
> };

I didn't use initializers because they initialize the entire data structure.
In case of struct vfs_lookup, unless the LOOKUP_OPEN flag is set, then the
open_intent doesn't need initialization. We could use a DEFINE_... macro; not
sure this would improve anything though.

> > +
> > + return permission(file->f_path.dentry->d_inode, mask, &lookup);
> > }
> >
> > /*

Thanks,
Andreas