Re: [PATCH] misc: pass miscdevice through file's private_data

From: Greg KH
Date: Fri Jan 09 2015 - 18:02:59 EST


On Fri, Dec 05, 2014 at 05:37:54AM +0100, Tom Van Braeckel wrote:
> Make the miscdevice accessible through the file's private_data.
>
> Previously, this was done only when an open() operation had been registered.
> But it's also useful in 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@xxxxxxxxx>
> ---
> drivers/char/misc.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/char/misc.c b/drivers/char/misc.c
> index ffa97d2..d6445de 100644
> --- a/drivers/char/misc.c
> +++ b/drivers/char/misc.c
> @@ -140,12 +140,17 @@ static int misc_open(struct inode * inode, struct file * file)
> goto fail;
> }
>
> + /*
> + * 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;
> + if (file->f_op->open)
> err = file->f_op->open(inode,file);
> - }
> fail:
> mutex_unlock(&misc_mtx);
> return err;
> --
> 1.9.1

Wait, didn't this break FUSE? Or was that some other variant of this
patch?

confused,

greg k-h
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