Re: [PATCH] carl9170: Fix error return -EAGAIN if not started

[Colin Ian King]

On 08/10/2021 06:58, Dan Carpenter wrote:
> On Fri, Oct 08, 2021 at 01:15:58AM +0100, Colin King wrote:
> > From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> >
> > There is an error return path where the error return is being
> > assigned to err rather than count and the error exit path does
> > not return -EAGAIN as expected. Fix this by setting the error
> > return to variable count as this is the value that is returned
> > at the end of the function.
> >
> > Addresses-Coverity: ("Unused value")
> > Fixes: 00c4da27a421 ("carl9170: firmware parser and debugfs code")
> > Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > ---
> >   drivers/net/wireless/ath/carl9170/debug.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/wireless/ath/carl9170/debug.c b/drivers/net/wireless/ath/carl9170/debug.c
> > index bb40889d7c72..f163c6bdac8f 100644
> > --- a/drivers/net/wireless/ath/carl9170/debug.c
> > +++ b/drivers/net/wireless/ath/carl9170/debug.c
> > @@ -628,7 +628,7 @@ static ssize_t carl9170_debugfs_bug_write(struct ar9170 *ar, const char *buf,
> >   
> >   	case 'R':
> >   		if (!IS_STARTED(ar)) {
> > -			err = -EAGAIN;
> > +			count = -EAGAIN;
> >   			goto out;
>
> This is ugly.  The bug wouldn't have happened with a direct return, it's
> only the goto out which causes it.  Better to replace all the error
> paths with direct returns.  There are two other direct returns so it's
> not like a new thing...

Yep, I agree it was ugly, I was trying to keep to the coding style and 
reduce the patch delta size. I can do a V2 if the maintainers deem it's 
a cleaner solution.

> Goto out on the success path is fine here, though.

Yep. I believe that a goto to one exit return point (may possibly?) make 
the code smaller rather than a sprinkling of returns in a function, so 
I'm never sure if this is a win or not with these kind of cases.

Colin
> regards,
> dan carpenter