Re: [PATCH] USB: cdc-wdm: Call wake_up_all() when clearing WDM_IN_USE bit.

[Greg KH <greg@kroah.com>]

On Thu, May 21, 2020 at 08:31:29AM +0900, Tetsuo Handa wrote:
> Since e.g. wdm_flush() calls wait_event() on WDM_IN_USE bit,
> make sure to call wake_up_all() when clearing WDM_IN_USE bit.

I'm sorry, but I don't understand what this changelog text is trying to
say.  Can you reword this differently?

> 
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

And is this a bugfix?  For what?  Does it need to go to stable kernels?

> ---
>  drivers/usb/class/cdc-wdm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
> index e3db6fbeadef..bf2a6deb7b08 100644
> --- a/drivers/usb/class/cdc-wdm.c
> +++ b/drivers/usb/class/cdc-wdm.c
> @@ -151,7 +151,7 @@ static void wdm_out_callback(struct urb *urb)
>  	kfree(desc->outbuf);
>  	desc->outbuf = NULL;
>  	clear_bit(WDM_IN_USE, &desc->flags);
> -	wake_up(&desc->wait);
> +	wake_up_all(&desc->wait);
>  }
>  
>  static void wdm_in_callback(struct urb *urb)
> @@ -426,6 +426,7 @@ static ssize_t wdm_write
>  		clear_bit(WDM_IN_USE, &desc->flags);
>  		dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
>  		rv = usb_translate_errors(rv);
> +		wake_up_all(&desc->wait);

Is this a fix for two different issues?

confused,

greg k-h