netdev - Re: [PATCH v2 02/14] sh_eth: fix invalid context bug while changing link options by ethtool

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Message-ID: <b943145f-fe1c-f38c-d060-9cba3efa7689@cogentembedded.com>
Date:   Fri, 6 Jul 2018 21:43:52 +0300
From:   Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:     Vladimir Zapolskiy <vladimir_zapolskiy@...tor.com>,
        "David S . Miller" <davem@...emloft.net>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH v2 02/14] sh_eth: fix invalid context bug while changing
 link options by ethtool

On 07/04/2018 11:12 AM, Vladimir Zapolskiy wrote:

> The change fixes sleep in atomic context bug, which is encountered
> every time when link settings are changed by ethtool.
> 
> Since commit 35b5f6b1a82b ("PHYLIB: Locking fixes for PHY I/O
> potentially sleeping") phy_start_aneg() function utilizes a mutex
> to serialize changes to phy state, however that helper function is
> called in atomic context under a grabbed spinlock, because
> phy_start_aneg() is called by phy_ethtool_ksettings_set() and by
> replaced phy_ethtool_sset() helpers from phylib.

   So if all this boils down to phy_start_aneg(), shouldn't this patch
precede patch #1. Or even fixing both call chains with 1 patch? :-)

> Now duplex mode setting is enforced in sh_eth_adjust_link() only,
> also now RX/TX is disabled when link is put down or modifications
> to E-MAC registers ECMR and GECMR are expected for both cases of
> checked and ignored link status pin state from E-MAC interrupt handler.
> 
> For reference the change is a partial rework of commit 1e1b812bbe10
> ("sh_eth: fix handling of no LINK signal").
> 
> Fixes: dc19e4e5e02f ("sh: sh_eth: Add support ethtool")
> Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@...tor.com>
[...]

Reviewed-by: Sergei Shtylyov <sergei.shtylyov@...entembedded.com>

MBR, Sergei