linux-kernel - Re: [PATCH 2/2] octeon_ep: Fix irq releasing in the error handling path of octep_request

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Message-ID: <eec880be771e75d60ead01cbf71d83fe070ccde8.camel@redhat.com>
Date:   Tue, 17 May 2022 10:35:26 +0200
From:   Paolo Abeni <pabeni@...hat.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     Veerasenareddy Burru <vburru@...vell.com>,
        Abhijit Ayarekar <aayarekar@...vell.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Satananda Burla <sburla@...vell.com>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH 2/2] octeon_ep: Fix irq releasing in the error handling
 path of octep_request_irqs()

On Tue, 2022-05-17 at 08:28 +0300, Dan Carpenter wrote:
> On Sun, May 15, 2022 at 05:56:45PM +0200, Christophe JAILLET wrote:
> > For the error handling to work as expected, the index in the
> > 'oct->msix_entries' array must be tweaked because, when the irq are
> > requested there is:
> > 	msix_entry = &oct->msix_entries[i + num_non_ioq_msix];
> > 
> > So in the error handling path, 'i + num_non_ioq_msix' should be used
> > instead of 'i'.
> > 
> > The 2nd argument of free_irq() also needs to be adjusted.
> > 
> > Fixes: 37d79d059606 ("octeon_ep: add Tx/Rx processing and interrupt support")
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> > ---
> > I think that the wording above is awful, but I'm sure you get it.
> > Feel free to rephrase everything to have it more readable.
> > ---
> >  drivers/net/ethernet/marvell/octeon_ep/octep_main.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
> > index 6b60a03574a0..4dcae805422b 100644
> > --- a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
> > +++ b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
> > @@ -257,10 +257,12 @@ static int octep_request_irqs(struct octep_device *oct)
> >  
> >  	return 0;
> >  ioq_irq_err:
> > +	i += num_non_ioq_msix;
> >  	while (i > num_non_ioq_msix) {
> 
> This makes my mind hurt so badly.  Can we not just have two variables
> for the two different loops instead of re-using i?
> 
> >  		--i;
> >  		irq_set_affinity_hint(oct->msix_entries[i].vector, NULL);
> > -		free_irq(oct->msix_entries[i].vector, oct->ioq_vector[i]);
> > +		free_irq(oct->msix_entries[i].vector,
> > +			 oct->ioq_vector[i - num_non_ioq_msix]);
> >  	}
> 
> ioq_irq_err:
>         while (--j >= 0) {
>                 ioq_vector = oct->ioq_vector[j];
>                 msix_entry = &oct->msix_entries[j + num_non_ioq_msix];
> 
>                 irq_set_affinity_hint(msix_entry->vector, NULL);
>                 free_irq(msix_entry->vector, ioq_vector);
>         }
> 
> regards,
> dan carpenter

I agree the above would be more readable. @Christophe: could you please
refactor the code as per Dan's suggestion?

Thanks!

Paolo