netdev - Re: [PATCH net-next 0/2] net: dsa: don't unmask port bitmaps

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Message-ID: <20171023211109.GA23689@lunn.ch>
Date:   Mon, 23 Oct 2017 23:11:09 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Vivien Didelot <vivien.didelot@...oirfairelinux.com>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...oirfairelinux.com,
        "David S. Miller" <davem@...emloft.net>,
        Florian Fainelli <f.fainelli@...il.com>
Subject: Re: [PATCH net-next 0/2] net: dsa: don't unmask port bitmaps

On Mon, Oct 23, 2017 at 02:17:29PM -0400, Vivien Didelot wrote:
> DSA has several bitmaps to store the type of ports: cpu_port_mask,
> dsa_port_mask and enabled_port_mask. But the code is inconsistently
> unmasking them.
> 
> The legacy code tries to unmask cpu_port_mask and dsa_port_mask but
> skips enabled_port_mask.
> 
> The new bindings unmasks cpu_port_mask and enabled_port_mask but skips
> dsa_port_mask.
> 
> In fact there is no need to unmask them because we are in the error
> path, and they won't be used after. Instead of fixing the unmasking,
> simply remove them.

Hi Vivien

I'm not looked at the code, travelling and don't have time.

What happens if the failure is -PROBE_DEFERRED, and it tried again
later. Will these masks be set back to 0? Or will they retain the old
values? I think there is supposed to be symmetry here, so that we undo
what we did, and so the next time we try again, we start from a good
state.

	Andrew