On Tue, May 29, 2018 at 09:15:30AM -0700, Guenter Roeck wrote:
> On Tue, May 29, 2018 at 05:30:47PM +0200, Greg Kroah-Hartman wrote:
> > When calling debugfs functions, there is no need to ever check the
> > return value. The function can work or not, but the code logic should
> > never do something different based on this.
> >
> > Clean up the fsusb302 driver to not care about the dentry being created,
> > or if the root directory was created, as the code should work properly
> > either way. We do not need to save the dentry anymore as things are
> > properly cleaned up when we remove the root directory.
> >
> > Note, this driver seems to only work for one device per system,
> > otherwise the debugfs directories are going to get confused when a
> > device is removed.
> >
> > Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> > Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> > Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> > Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > Cc: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/usb/typec/fusb302/fusb302.c | 24 +++++++-----------------
> > 1 file changed, 7 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/usb/typec/fusb302/fusb302.c b/drivers/usb/typec/fusb302/fusb302.c
> > index 9c1eba9ea004..07b07ddf6af0 100644
> > --- a/drivers/usb/typec/fusb302/fusb302.c
> > +++ b/drivers/usb/typec/fusb302/fusb302.c
> > @@ -117,7 +117,6 @@ struct fusb302_chip {
> > u32 snk_pdo[PDO_MAX_OBJECTS];
> >
> > #ifdef CONFIG_DEBUG_FS
> > - struct dentry *dentry;
> > /* lock for log buffer access */
> > struct mutex logbuffer_lock;
> > int logbuffer_head;
> > @@ -215,33 +214,26 @@ DEFINE_SHOW_ATTRIBUTE(fusb302_debug);
> >
> > static struct dentry *rootdir;
> >
> > -static int fusb302_debugfs_init(struct fusb302_chip *chip)
> > +static void fusb302_debugfs_init(struct fusb302_chip *chip)
> > {
> > mutex_init(&chip->logbuffer_lock);
> > - if (!rootdir) {
> > + if (!rootdir)
> > rootdir = debugfs_create_dir("fusb302", NULL);
> > - if (!rootdir)
> > - return -ENOMEM;
> > - }
> > -
> > - chip->dentry = debugfs_create_file(dev_name(chip->dev),
> > - S_IFREG | 0444, rootdir,
> > - chip, &fusb302_debug_fops);
> >
> > - return 0;
> > + debugfs_create_file(dev_name(chip->dev), S_IFREG | 0444, rootdir, chip,
> > + &fusb302_debug_fops);
> > }
> >
> > static void fusb302_debugfs_exit(struct fusb302_chip *chip)
> > {
> > - debugfs_remove(chip->dentry);
> > - debugfs_remove(rootdir);
> > + debugfs_remove_recursive(rootdir);
>
> The idea was that debugfs_remove() would only remove the root directory
> if nothing else was in it. This was the reason for the preceding
> debugfs_remove(chip->dentry) followed by debugfs_remove(). Your patch
> changes this behavior. "... this driver seems to only work for one
> device per system" is introduced by your patch and was not previously
> the case.
Ah, that makes more sense. Nice hack :)
Why not just have a new directory per device like "most" drivers have?
That would make this a bit simpler to manage. Mind of I change the code
that way? Hm, you still end up having to save off a dentry that way,
ah, it's the same either way...
thanks,
greg k-h
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