Nouveau - Feb 2022 - [PATCH 1/6] drivers: usb: remove usage of list iterator past the loop body

On Mon, Feb 28, 2022 at 12:08:17PM +0100, Jakob Koschel
wrote:
> diff --git a/drivers/usb/gadget/udc/at91_udc.c
b/drivers/usb/gadget/udc/at91_udc.c
> index 9040a0561466..0fd0307bc07b 100644
> --- a/drivers/usb/gadget/udc/at91_udc.c
> +++ b/drivers/usb/gadget/udc/at91_udc.c
> @@ -150,13 +150,14 @@ static void proc_ep_show(struct seq_file *s, struct
at91_ep *ep)
>  	if (list_empty (&ep->queue))
>  		seq_printf(s, "\t(queue empty)\n");
> 
> -	else list_for_each_entry (req, &ep->queue, queue) {
> -		unsigned	length = req->req.actual;
> +	else
> +		list_for_each_entry(req, &ep->queue, queue) {
> +			unsigned int	length = req->req.actual;
> 
> -		seq_printf(s, "\treq %p len %d/%d buf %p\n",
> -				&req->req, length,
> -				req->req.length, req->req.buf);
> -	}
> +			seq_printf(s, "\treq %p len %d/%d buf %p\n",
> +					&req->req, length,
> +					req->req.length, req->req.buf);
> +		}
Don't make unrelated white space changes.  It just makes the patch
harder to review.  As you're writing the patch make note of any
additional changes and do them later in a separate patch.

Also a multi-line indent gets curly braces for readability even though
it's not required by C.  And then both sides would get curly braces.
>  	spin_unlock_irqrestore(&udc->lock, flags);
>  }
> 
> @@ -226,7 +227,7 @@ static int proc_udc_show(struct seq_file *s, void
*unused)
> 
>  	if (udc->enabled && udc->vbus) {
>  		proc_ep_show(s, &udc->ep[0]);
> -		list_for_each_entry (ep, &udc->gadget.ep_list, ep.ep_list) {
> +		list_for_each_entry(ep, &udc->gadget.ep_list, ep.ep_list) {
Another unrelated change.
>  			if (ep->ep.desc)
>  				proc_ep_show(s, ep);
>  		}

[ snip ]
> diff --git a/drivers/usb/gadget/udc/net2272.c
b/drivers/usb/gadget/udc/net2272.c
> index 7c38057dcb4a..bb59200f1596 100644
> --- a/drivers/usb/gadget/udc/net2272.c
> +++ b/drivers/usb/gadget/udc/net2272.c
> @@ -926,7 +926,8 @@ static int
>  net2272_dequeue(struct usb_ep *_ep, struct usb_request *_req)
>  {
>  	struct net2272_ep *ep;
> -	struct net2272_request *req;
> +	struct net2272_request *req = NULL;
> +	struct net2272_request *tmp;
>  	unsigned long flags;
>  	int stopped;
> 
> @@ -939,11 +940,13 @@ net2272_dequeue(struct usb_ep *_ep, struct
usb_request *_req)
>  	ep->stopped = 1;
> 
>  	/* make sure it's still queued on this endpoint */
> -	list_for_each_entry(req, &ep->queue, queue) {
> -		if (&req->req == _req)
> +	list_for_each_entry(tmp, &ep->queue, queue) {
> +		if (&tmp->req == _req) {
> +			req = tmp;
>  			break;
> +		}
>  	}
> -	if (&req->req != _req) {
> +	if (!req) {
>  		ep->stopped = stopped;
>  		spin_unlock_irqrestore(&ep->dev->lock, flags);
>  		return -EINVAL;
> @@ -954,7 +957,6 @@ net2272_dequeue(struct usb_ep *_ep, struct usb_request
*_req)
>  		dev_dbg(ep->dev->dev, "unlink (%s) pio\n",
_ep->name);
>  		net2272_done(ep, req, -ECONNRESET);
>  	}
> -	req = NULL;
Another unrelated change.  These are all good changes but send them as
separate patches.
>  	ep->stopped = stopped;
> 
>  	spin_unlock_irqrestore(&ep->dev->lock, flags);
regards,
dan carpenter

> On 28. Feb 2022, at 12:24, Dan Carpenter <dan.carpenter at
oracle.com> wrote:
> 
> On Mon, Feb 28, 2022 at 12:08:17PM +0100, Jakob Koschel wrote:
>> diff --git a/drivers/usb/gadget/udc/at91_udc.c
b/drivers/usb/gadget/udc/at91_udc.c
>> index 9040a0561466..0fd0307bc07b 100644
>> --- a/drivers/usb/gadget/udc/at91_udc.c
>> +++ b/drivers/usb/gadget/udc/at91_udc.c
>> @@ -150,13 +150,14 @@ static void proc_ep_show(struct seq_file *s,
struct at91_ep *ep)
>> 	if (list_empty (&ep->queue))
>> 		seq_printf(s, "\t(queue empty)\n");
>> 
>> -	else list_for_each_entry (req, &ep->queue, queue) {
>> -		unsigned	length = req->req.actual;
>> +	else
>> +		list_for_each_entry(req, &ep->queue, queue) {
>> +			unsigned int	length = req->req.actual;
>> 
>> -		seq_printf(s, "\treq %p len %d/%d buf %p\n",
>> -				&req->req, length,
>> -				req->req.length, req->req.buf);
>> -	}
>> +			seq_printf(s, "\treq %p len %d/%d buf %p\n",
>> +					&req->req, length,
>> +					req->req.length, req->req.buf);
>> +		}
> 
> Don't make unrelated white space changes.  It just makes the patch
> harder to review.  As you're writing the patch make note of any
> additional changes and do them later in a separate patch.
> 
> Also a multi-line indent gets curly braces for readability even though
> it's not required by C.  And then both sides would get curly braces.
> 
>> 	spin_unlock_irqrestore(&udc->lock, flags);
>> }
>> 
>> @@ -226,7 +227,7 @@ static int proc_udc_show(struct seq_file *s, void
*unused)
>> 
>> 	if (udc->enabled && udc->vbus) {
>> 		proc_ep_show(s, &udc->ep[0]);
>> -		list_for_each_entry (ep, &udc->gadget.ep_list, ep.ep_list) {
>> +		list_for_each_entry(ep, &udc->gadget.ep_list, ep.ep_list) {
> 
> Another unrelated change.
> 
>> 			if (ep->ep.desc)
>> 				proc_ep_show(s, ep);
>> 		}
> 
> 
> [ snip ]
Thanks for pointing out, I'll remove the changes here and note them down
to send them separately.
> 
>> diff --git a/drivers/usb/gadget/udc/net2272.c
b/drivers/usb/gadget/udc/net2272.c
>> index 7c38057dcb4a..bb59200f1596 100644
>> --- a/drivers/usb/gadget/udc/net2272.c
>> +++ b/drivers/usb/gadget/udc/net2272.c
>> @@ -926,7 +926,8 @@ static int
>> net2272_dequeue(struct usb_ep *_ep, struct usb_request *_req)
>> {
>> 	struct net2272_ep *ep;
>> -	struct net2272_request *req;
>> +	struct net2272_request *req = NULL;
>> +	struct net2272_request *tmp;
>> 	unsigned long flags;
>> 	int stopped;
>> 
>> @@ -939,11 +940,13 @@ net2272_dequeue(struct usb_ep *_ep, struct
usb_request *_req)
>> 	ep->stopped = 1;
>> 
>> 	/* make sure it's still queued on this endpoint */
>> -	list_for_each_entry(req, &ep->queue, queue) {
>> -		if (&req->req == _req)
>> +	list_for_each_entry(tmp, &ep->queue, queue) {
>> +		if (&tmp->req == _req) {
>> +			req = tmp;
>> 			break;
>> +		}
>> 	}
>> -	if (&req->req != _req) {
>> +	if (!req) {
>> 		ep->stopped = stopped;
>> 		spin_unlock_irqrestore(&ep->dev->lock, flags);
>> 		return -EINVAL;
>> @@ -954,7 +957,6 @@ net2272_dequeue(struct usb_ep *_ep, struct
usb_request *_req)
>> 		dev_dbg(ep->dev->dev, "unlink (%s) pio\n",
_ep->name);
>> 		net2272_done(ep, req, -ECONNRESET);
>> 	}
>> -	req = NULL;
> 
> Another unrelated change.  These are all good changes but send them as
> separate patches.
You are referring to the req = NULL, right?

I've changed the use of 'req' in the same function and assumed that
I can
just remove the unnecessary statement. But if it's better to do separately
I'll do that.
> 
>> 	ep->stopped = stopped;
>> 
>> 	spin_unlock_irqrestore(&ep->dev->lock, flags);
> 
> regards,
> dan carpenter
thanks,
Jakob Koschel

On Mon, Feb 28, 2022 at 01:03:36PM +0100, Jakob Koschel
wrote:
> >> @@ -954,7 +957,6 @@ net2272_dequeue(struct usb_ep *_ep, struct
usb_request *_req)
> >> 		dev_dbg(ep->dev->dev, "unlink (%s) pio\n",
_ep->name);
> >> 		net2272_done(ep, req, -ECONNRESET);
> >> 	}
> >> -	req = NULL;
> > 
> > Another unrelated change.  These are all good changes but send them as
> > separate patches.
> 
> You are referring to the req = NULL, right?
Yes.
> 
> I've changed the use of 'req' in the same function and assumed
that I can
> just remove the unnecessary statement. But if it's better to do
separately
> I'll do that.
> 
These are all changes which made me pause during my review to figure out
why they were necessary.  The line between what is a related part of a
patch is a bit vague and some maintainers will ask you to add or subtract
from a patch depending on their individual tastes.  I don't really have
an exact answer, but I felt like this patch needs to be subtracted from.

Especially if there is a whole chunk of the patch which can be removed,
then to me, that obviously should be in a different patch.

regards,
dan carpenter

On Mon, 2022-02-28 at 14:24 +0300, Dan Carpenter wrote:
> a multi-line indent gets curly braces for readability even though
> it's not required by C.  And then both sides would get curly braces.
That's more your personal preference than a coding style guideline.

On Mon, Feb 28, 2022 at 10:20:28AM -0800, Joe Perches
wrote:
> On Mon, 2022-02-28 at 14:24 +0300, Dan Carpenter wrote:
> 
> > a multi-line indent gets curly braces for readability even though
> > it's not required by C.  And then both sides would get curly
braces.
> 
> That's more your personal preference than a coding style guideline.
> 
It's a USB patch.  I thought Greg prefered it that way.  Greg has some
specific style things which he likes and I have adopted and some I
pretend not to see.

regards,
dan carpenter