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Date:   Fri, 16 Apr 2021 14:12:47 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Tony Nguyen <anthony.l.nguyen@intel.com>
Cc:     davem@davemloft.net, Grzegorz Siwik <grzegorz.siwik@intel.com>,
        netdev@vger.kernel.org, sassmann@redhat.com,
        Dave Switzer <david.switzer@intel.com>
Subject: Re: [PATCH net-next 2/6] igb: Add double-check MTA_REGISTER for
 i210 and i211
Message-ID: <20210416141247.7a8048ad@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
In-Reply-To: <20210416204500.2012073-3-anthony.l.nguyen@intel.com>
References: <20210416204500.2012073-1-anthony.l.nguyen@intel.com>
        <20210416204500.2012073-3-anthony.l.nguyen@intel.com>
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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.