From: Giuseppe CAVALLARO <peppe.cavallaro@st.com>
To: David Miller <davem@davemloft.net>
Cc: <netdev@vger.kernel.org>
Subject: Re: [PATCH (net.git) 5/6] stmmac: remove useless check in the stmmac_tx_clean
Date: Thu, 27 Feb 2014 10:59:01 +0100 [thread overview]
Message-ID: <530F0C65.4080905@st.com> (raw)
In-Reply-To: <20140226.161422.431061479377150157.davem@davemloft.net>
On 2/26/2014 10:14 PM, David Miller wrote:
> From: Giuseppe Cavallaro <peppe.cavallaro@st.com>
> Date: Wed, 26 Feb 2014 09:01:06 +0100
>
>> There is an useless if condition that this patch is removing
>> when the driver cleans the tx resources.
>>
>> Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
>
> It is not useless, the first check is optimistic and lock free.
>
> You must retest the condition under the lock in order to avoid
> spurious wakeups.
>
> Such a spurious wakeup could overlap another asynchronous context
> filling the TX queue and sleeping it, resulting in corruption.
>
> Furthermore, that cleanup patch in this series is absolutely not
> appropriate for 'net' which is for real bug fixes only. Specifically
> I'm talking about patch #4.
>
>
Ok I will send the patches w/o the #4. Thx for your advice
peppe
next prev parent reply other threads:[~2014-02-27 9:59 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-26 8:01 [PATCH (net.git) 0/6] stmmac: fix EEE and chained mode Giuseppe Cavallaro
2014-02-26 8:01 ` [PATCH (net.git) 1/6 (v2)] stmmac: disable at run-time the EEE if not supported Giuseppe Cavallaro
2014-02-26 8:01 ` [PATCH (net.git) 2/6] stmmac: fix and better tune the default buffer sizes Giuseppe Cavallaro
2014-02-26 8:01 ` [PATCH (net.git) 3/6] stmmac: dwmac-sti: fix broken STiD127 compatibility Giuseppe Cavallaro
2014-02-26 8:01 ` [PATCH (net.git) 4/6] stmmac: dwmac-sti: remove useless tx_retime_srcs Giuseppe Cavallaro
2014-02-26 8:01 ` [PATCH (net.git) 5/6] stmmac: remove useless check in the stmmac_tx_clean Giuseppe Cavallaro
2014-02-26 21:14 ` David Miller
2014-02-27 9:59 ` Giuseppe CAVALLARO [this message]
2014-02-26 8:01 ` [PATCH (net.git) 6/6] stmmac: fix chained mode Giuseppe Cavallaro
-- strict thread matches above, loose matches on Subject: below --
2014-02-25 9:58 [PATCH (net.git) 1/6] stmmac: disable at run-time the EEE if not supported Giuseppe Cavallaro
2014-02-25 9:58 ` [PATCH (net.git) 5/6] stmmac: remove useless check in the stmmac_tx_clean Giuseppe Cavallaro
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