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.
Guenter
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