misc: always assign miscdevice to file->private_data in open()

As of now, a miscdevice driver has to provide an implementation of
the open() file operation if it wants to have misc_open() assign a
pointer to struct miscdevice to file->private_data for other file
operations to use (given the user calls open()).

This leads to situations where a miscdevice driver that doesn't need
internal operations during open() has to implement open() that only
returns immediately, in order to use the data in private_data in other
fops.

This provides consistent behaviour for miscdevice developers and will
always provide the pointer in private_data. A driver's open() fop would,
of course, just overwrite it, when using private_data itself.

Signed-off-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Martin Kepplinger 2014-10-29 20:22:56 +01:00 committed by Greg Kroah-Hartman
parent 04a258c162
commit 32eca22180

View file

@ -142,8 +142,8 @@ static int misc_open(struct inode * inode, struct file * file)
err = 0;
replace_fops(file, new_fops);
file->private_data = c;
if (file->f_op->open) {
file->private_data = c;
err = file->f_op->open(inode,file);
}
fail: