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SubjectRe: [PATCH] Misc: pass miscdevice through file's private_data
On Fri, Dec 05, 2014 at 12:01:03AM +0100, Tom Van Braeckel wrote:
> > >
> > > + /*
> > > + * Place the miscdevice in the file's
> > > + * private_data so it can be used by the
> > > + * file operations, including f_op->open below
> > > + */
> > > + file->private_data = c;
> > > +
> > > err = 0;
> > > replace_fops(file, new_fops);
> > > if (file->f_op->open) {
> > > - file->private_data = c;
> > > err = file->f_op->open(inode,file);
> > > }
> >
> > These braces aren't needed anymore, right?
> >
> > Also, what is this now going to break? :)
> >
> > thanks,
> >
> > greg k-h
>
> Thanks for the fast feedback!
>
> Good point, so I made a list of all drivers that use private_data (find drivers/ -iname "*.c" -exec grep -l private_data {} \; | sort -u) and manually verified that all of them either register an open() operation, do not use the misc subsystem, or matched because of vm_private_data.
>
> >From this investigation, I conclude that it does not break anything.
>
> I also removed the unnecessary curly braces. Please find the new patch below.
>
>
> misc: pass miscdevice through file's private_data
>
> Place the miscdevice in the file's private_data to be used by the file operations.
>
> Previously, this was done only when an open() operation had been registered.
> But it is also useful in the other file operations, so we pass it on unconditionally.
>
> All drivers that use private_data and misc_register() were checked to ensure they register an open() operation,
> in order to verify that this improvement does not break any existing driver that uses the misc subsystem.
>
> Signed-off-by: Tom Van Braeckel <tomvanbraeckel@gmail.com>
> ---
> drivers/char/misc.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)

Please resend this in a format I can apply it in (standalone, lines
properly wrapped, etc.)

thanks,

greg k-h


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