linux-kernel - Re: [PATCH 26/26] usb: gadget: udc: s3c2410: replace usage of rc to check if a list element was found

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Message-ID: <3655d921-3798-0a01-1b7a-32261389dde5@canonical.com>
Date:   Mon, 7 Mar 2022 13:13:44 +0100
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
To:     Jakob Koschel <jakobkoschel@...il.com>,
        Greg Kroah-Hartman <greg@...ah.com>
Cc:     linux-kernel@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Felipe Balbi <balbi@...nel.org>, Joel Stanley <joel@....id.au>,
        Andrew Jeffery <andrew@...id.au>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Claudiu Beznea <claudiu.beznea@...rochip.com>,
        Cristian Birsan <cristian.birsan@...rochip.com>,
        Al Cooper <alcooperx@...il.com>, Li Yang <leoyang.li@....com>,
        Vladimir Zapolskiy <vz@...ia.com>,
        Daniel Mack <daniel@...que.org>,
        Haojian Zhuang <haojian.zhuang@...il.com>,
        Robert Jarzmik <robert.jarzmik@...e.fr>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Michal Simek <michal.simek@...inx.com>,
        "open list:USB GADGET/PERIPHERAL SUBSYSTEM" 
        <linux-usb@...r.kernel.org>, Mike Rapoport <rppt@...nel.org>,
        Brian Johannesmeyer <bjohannesmeyer@...il.com>,
        Cristiano Giuffrida <c.giuffrida@...nl>,
        "Bos, H.J." <h.j.bos@...nl>
Subject: Re: [PATCH 26/26] usb: gadget: udc: s3c2410: replace usage of rc to
 check if a list element was found

On 06/03/2022 18:50, Jakob Koschel wrote:
> To move the list iterator variable into the list_for_each_entry_*()
> macro in the future it should be avoided to use the list iterator
> variable after the loop body.
> 
> To *never* use the list iterator variable after the loop it was
> concluded to use a separate iterator variable [1].
> 
> This removes the need to check the rc value to determine if the
> break/goto was hit and can be made more obvious
> by checking if the variable was set within the list traversal loop.
> 
> Link: https://lore.kernel.org/all/YhdfEIwI4EdtHdym@kroah.com/
> Signed-off-by: Jakob Koschel <jakobkoschel@...il.com>
> ---
>  drivers/usb/gadget/udc/s3c2410_udc.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/s3c2410_udc.c b/drivers/usb/gadget/udc/s3c2410_udc.c
> index e3931da24277..fe6ecb0d16d1 100644
> --- a/drivers/usb/gadget/udc/s3c2410_udc.c
> +++ b/drivers/usb/gadget/udc/s3c2410_udc.c
> @@ -1265,7 +1265,7 @@ static int s3c2410_udc_dequeue(struct usb_ep *_ep, struct usb_request *_req)
>  	struct s3c2410_ep	*ep = to_s3c2410_ep(_ep);
>  	int			retval = -EINVAL;
>  	unsigned long		flags;
> -	struct s3c2410_request	*req = NULL;
> +	struct s3c2410_request	*req = NULL, *tmp;
>  
>  	dprintk(DEBUG_VERBOSE, "%s(%p,%p)\n", __func__, _ep, _req);
>  
> @@ -1277,16 +1277,17 @@ static int s3c2410_udc_dequeue(struct usb_ep *_ep, struct usb_request *_req)
>  
>  	local_irq_save(flags);
>  
> -	list_for_each_entry(req, &ep->queue, queue) {
> -		if (&req->req == _req) {
> -			list_del_init(&req->queue);
> +	list_for_each_entry(tmp, &ep->queue, queue) {
> +		if (&tmp->req == _req) {
> +			list_del_init(&tmp->queue);
>  			_req->status = -ECONNRESET;
> +			req = tmp;
>  			retval = 0;
>  			break;
>  		}
>  	}
>  
> -	if (retval == 0) {
> +	if (req) {

I saw comments from Greg about it, so please keep similar approach here
as in patch 25. I propose to keep retval.

With retval restored:
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>

Best regards,
Krzysztof