Re: [PATCH net-next 2/6] igb: Add double-check MTA_REGISTER for i210 and i211

From: "Nguyen, Anthony L" <anthony.l.nguyen@intel.com>
To: "kuba@kernel.org" <kuba@kernel.org>
Cc: "davem@davemloft.net" <davem@davemloft.net>,
	"Siwik, Grzegorz" <grzegorz.siwik@intel.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"sassmann@redhat.com" <sassmann@redhat.com>,
	"Switzer, David" <david.switzer@intel.com>
Subject: Re: [PATCH net-next 2/6] igb: Add double-check MTA_REGISTER for i210 and i211
Date: Tue, 20 Apr 2021 16:22:47 +0000	[thread overview]
Message-ID: <b2850afee64efb6af2415cb3db75d4de14f3a1e2.camel@intel.com> (raw)
In-Reply-To: <20210416141247.7a8048ad@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>

On Fri, 2021-04-16 at 14:12 -0700, Jakub Kicinski wrote:
> On Fri, 16 Apr 2021 13:44:56 -0700 Tony Nguyen wrote:
> > +	bool is_failed;
> > +	int i;
> > +
> > +	do {
> > +		is_failed = false;
> > +		for (i = hw->mac.mta_reg_count - 1; i >= 0; i--) {
> > +			if (array_rd32(E1000_MTA, i) != hw-
> > >mac.mta_shadow[i]) {
> > +				is_failed = true;
> > +				array_wr32(E1000_MTA, i, hw-
> > >mac.mta_shadow[i]);
> > +				wrfl();
> > +				break;
> > +			}
> > +		}
> > +	} while (is_failed);
> 
> Looks like a potential infinite loop on persistent failure.
> Also you don't need "is_failed", you can use while (i >= 0), or
> assign i = hw->mac.mta_reg_count, or consider using a goto. 

We will make a follow on patch to address these issues.

Thanks,
Tony