linux-kernel - Re: [PATCH v2 27/31] usb/gadget/snps_udc_core: Remove struct timer

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Date:   Thu, 21 Sep 2017 16:06:13 +0200
From:   Michal Nazarewicz <mina86@...a86.com>
To:     Kees Cook <keescook@...omium.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Kees Cook <keescook@...omium.org>, Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Raviteja Garimella <raviteja.garimella@...adcom.com>,
        "Gustavo A. R. Silva" <garsilva@...eddedor.com>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 27/31] usb/gadget/snps_udc_core: Remove struct timer_list.data use

On Wed, Sep 20 2017, Kees Cook wrote:
> If the probe fails, udc_remove() will not be called, so there is no
> reason to make del_timer_sync() calls conditional. As a result, use of
> the .data field can be dropped, in support of making removing this field
> entirely from struct timer_list.
>
> Cc: Felipe Balbi <balbi@...nel.org>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Raviteja Garimella <raviteja.garimella@...adcom.com>
> Cc: Michal Nazarewicz <mina86@...a86.com>

Acked-by: Michal Nazarewicz <mina86@...a86.com>

> Cc: "Gustavo A. R. Silva" <garsilva@...eddedor.com>
> Cc: linux-usb@...r.kernel.org
> Signed-off-by: Kees Cook <keescook@...omium.org>
> ---
>  drivers/usb/gadget/udc/snps_udc_core.c | 14 ++++----------
>  1 file changed, 4 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/snps_udc_core.c b/drivers/usb/gadget/udc/snps_udc_core.c
> index 5460e5ba1c3c..e05bdc16e1e3 100644
> --- a/drivers/usb/gadget/udc/snps_udc_core.c
> +++ b/drivers/usb/gadget/udc/snps_udc_core.c
> @@ -3067,14 +3067,12 @@ void udc_remove(struct udc *dev)
>  	stop_timer++;
>  	if (timer_pending(&udc_timer))
>  		wait_for_completion(&on_exit);
> -	if (udc_timer.data)
> -		del_timer_sync(&udc_timer);
> +	del_timer_sync(&udc_timer);
>  	/* remove pollstall timer */
>  	stop_pollstall_timer++;
>  	if (timer_pending(&udc_pollstall_timer))
>  		wait_for_completion(&on_pollstall_exit);
> -	if (udc_pollstall_timer.data)
> -		del_timer_sync(&udc_pollstall_timer);
> +	del_timer_sync(&udc_pollstall_timer);
>  	udc = NULL;
>  }
>  EXPORT_SYMBOL_GPL(udc_remove);
> @@ -3164,10 +3162,6 @@ int udc_probe(struct udc *dev)
>  	u32		reg;
>  	int		retval;
>  
> -	/* mark timer as not initialized */
> -	udc_timer.data = 0;
> -	udc_pollstall_timer.data = 0;
> -
>  	/* device struct setup */
>  	dev->gadget.ops = &udc_ops;
>  
> @@ -3207,8 +3201,8 @@ int udc_probe(struct udc *dev)
>  		goto finished;
>  
>  	/* timer init */
> -	setup_timer(&udc_timer, udc_timer_function, 1);
> -	setup_timer(&udc_pollstall_timer, udc_pollstall_timer_function, 1);
> +	setup_timer(&udc_timer, udc_timer_function, 0);
> +	setup_timer(&udc_pollstall_timer, udc_pollstall_timer_function, 0);
>  
>  	/* set SD */
>  	reg = readl(&dev->regs->ctl);

-- 
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»