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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     David Lechner <david@lechnology.com>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        Stephen Boyd <sboyd@codeaurora.org>
Subject: Re: [PATCH AUTOSEL for 4.15 104/124] clk: fix reentrancy of
 clk_enable() on UP systems
Thread-Topic: [PATCH AUTOSEL for 4.15 104/124] clk: fix reentrancy of
 clk_enable() on UP systems
Thread-Index: AQHTv5nJGUwlmQMprEeYWg0XJMUef6PXtiQAgBbCGAA=
Date:   Tue, 3 Apr 2018 03:27:41 +0000
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 <20180319154645.11350-104-alexander.levin@microsoft.com>
 <6a944b80-c86c-ca23-5ada-f088d84c9a80@lechnology.com>
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On Mon, Mar 19, 2018 at 10:55:16AM -0500, David Lechner wrote:
>On 03/19/2018 10:48 AM, Sasha Levin wrote:
>>From: David Lechner <david@lechnology.com>
>>
>>[ Upstream commit a12aa8a68dfef5de181f2e555aa950a0ab05411f ]
>>
>>Reentrant calls to clk_enable() are not working on UP systems. This is
>>caused by the fact spin_trylock_irqsave() always returns true when
>>CONFIG_SMP=3Dn (and CONFIG_DEBUG_SPINLOCK=3Dn) which causes the reference
>>counting to not work correctly when clk_enable_lock() is called twice
>>before clk_enable_unlock() is called (this happens when clk_enable()
>>is called from within another clk_enable()).
>>
>>This fixes the problem by skipping the call to spin_trylock_irqsave() on =
UP
>>systems and relying solely on reference counting. We also make sure to se=
t
>>flags in this case so that we are not returning an uninitialized value.
>>
>>Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
>>Signed-off-by: David Lechner <david@lechnology.com>
>>Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
>>Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
>>---
>
>I don't know of any existing bugs in v4.15 that this fixes, so I don't
>think this really fits the criteria for stable.
>

Now removed, thanks!=