From mboxrd@z Thu Jan  1 00:00:00 1970
From: Saravana Kannan <skannan@codeaurora.org>
Subject: Re: [PATCH 2/2] clk: Move init fields from clk to clk_hw
Date: Wed, 11 Apr 2012 12:57:44 -0700
Message-ID: <4F85E238.9050102@codeaurora.org>
References: <CAJOA=zN2cSSpM92oRnW0RyU_ZzyoQ=jthc-fAkf-P3z37uWt7w@mail.gmail.com> <1332214706-675-1-git-send-email-skannan@codeaurora.org> <1332214706-675-2-git-send-email-skannan@codeaurora.org> <20120320072018.GC32469@S2101-09.ap.freescale.net> <cbd6490459b9fd68875fec4a7c7de073.squirrel@www.codeaurora.org> <20120320094031.GI3852@pengutronix.de> <20120320141811.GF32469@S2101-09.ap.freescale.net> <20120320181050.GN3852@pengutronix.de> <4F68E34A.70207@codeaurora.org> <20120320231242.GP3852@pengutronix.de> <CAJOA=zOGTW7OqACWgJQW6HSPLVev+apdNhv4vNXjHTcp=7N+uQ@mail.gmail.com> <4F694484.1030706@codeaurora.org> <4F714397.6080608@codeaurora.org> <CAJOA=zOq=kYfZUEnnQT_D4w=Kpp5n7R=k9oOCrxF59P5W-nw-w@mail.gmail.com> <4F7E4752.4020007@codeaurora.org> <CAJOA=zMEN_im3-T+_uXB_mTu842o_fRkr9-7h=X18fKBoH46a
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Cc: Sascha Hauer <s.hauer@pengutronix.de>, Andrew Lunn <andrew@lunn.ch>, Grant Likely <grant.likely@secretlab.ca>, Jamie Iles <jamie@jamieiles.com>, Jeremy Kerr <jeremy.kerr@canonical.com>, Magnus Damm <magnus.damm@gmail.com>, Deepak Saxena <dsaxena@linaro.org>, linux-arm-kernel@lists.infradead.org, Arnd Bergman <arnd.bergmann@linaro.org>, linux-arm-msm@vger.kernel.org, Rob Herring <rob.herring@calxeda.com>, Russell King <linux@arm.linux.org.uk>, Thomas Gleixner <tglx@linutronix.de>, Richard Zhao <richard.zhao@linaro.org>, Shawn Guo <shawn.guo@freescale.com>, Paul Walmsley <paul@pwsan.com>, Linus Walleij <linus.walleij@stericsson.com>, Mark Brown <broonie@opensource.wolfsonmicro.com>, Stephen Boyd <sboyd@codeaurora.org>, linux-kernel@vger.kernel.org, Amit Kucheria <amit.kucheria@linaro.org>, Shawn Guo <shawn.guo@linaro.org>

On 04/11/2012 10:59 AM, Turquette, Mike wrote:
> On Thu, Apr 5, 2012 at 6:30 PM, Saravana Kannan<skannan@codeaurora.org>  wrote:
>> (*nudge*) (*nudge*) again :-)
>>
>> Sorry to keep nudging you on this often. The longer we wait for this, the
>> more churn it will cause later on. That's why I'm being persistent on this.
>> Also, once this goes in, I can start working on upstreaming MSM clock
>> support.

<SNIP>

> TL;DR: I think a combination of your change to expose the
> not-so-private parts of struct clk into struct clk_hw are OK and have
> real benefits for the clk-provider.h code.  However we need to
> implement it such that all the statically initialized data can be
> __initdata.

Sounds like a reasonable compromise.

> My only concern with this series is that platform clock code will
> access struct clk_hw members without the appropriate lock held (namely
> prepare_lock).  I'm a bit worried that there might be a case where
> some clock code access clk_hw->name when clk_hw has somehow been
> destroyed/altered (e.g. if clk_put every finally gets implemented...).
>   Besides clk_put are there any real instances where this might happen?

This problem is true for any struct/field marked as __init_data. So, I 
don't think this is a real problem. If someone is stupid enough to mark 
their data as __init_data and access them later, then there is not much 
we can do. Also, I believe the compiler throws out some warning when you 
try to access __init_data from non-init code.

> I'll be pushing my fixes branch out to the list soon.  Do you want to
> rebase this change on top of it taking into account the __initdata
> bits?

I thought it might be easier for you to base your changes on top of my 
patch. But I can try to rebase mine on top of your changes. Hopefully 
your fixes aren't crazy big/complex.

This is a busy week for me at work. I will try to send a patch in a day 
or two.

Thanks,
Saravana

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

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Date: Wed, 11 Apr 2012 12:57:44 -0700
From: Saravana Kannan <skannan@codeaurora.org>
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To: "Turquette, Mike" <mturquette@ti.com>
CC: Sascha Hauer <s.hauer@pengutronix.de>, Andrew Lunn <andrew@lunn.ch>,
        Grant Likely <grant.likely@secretlab.ca>,
        Jamie Iles <jamie@jamieiles.com>,
        Jeremy Kerr <jeremy.kerr@canonical.com>,
        Magnus Damm <magnus.damm@gmail.com>,
        Deepak Saxena <dsaxena@linaro.org>,
        linux-arm-kernel@lists.infradead.org,
        Arnd Bergman <arnd.bergmann@linaro.org>, linux-arm-msm@vger.kernel.org,
        Rob Herring <rob.herring@calxeda.com>,
        Russell King <linux@arm.linux.org.uk>,
        Thomas Gleixner <tglx@linutronix.de>,
        Richard Zhao <richard.zhao@linaro.org>,
        Shawn Guo <shawn.guo@freescale.com>, Paul Walmsley <paul@pwsan.com>,
        Linus Walleij <linus.walleij@stericsson.com>,
        Mark Brown <broonie@opensource.wolfsonmicro.com>,
        Stephen Boyd <sboyd@codeaurora.org>, linux-kernel@vger.kernel.org,
        Amit Kucheria <amit.kucheria@linaro.org>,
        Shawn Guo <shawn.guo@linaro.org>
Subject: Re: [PATCH 2/2] clk: Move init fields from clk to clk_hw
References: <CAJOA=zN2cSSpM92oRnW0RyU_ZzyoQ=jthc-fAkf-P3z37uWt7w@mail.gmail.com> <1332214706-675-1-git-send-email-skannan@codeaurora.org> <1332214706-675-2-git-send-email-skannan@codeaurora.org> <20120320072018.GC32469@S2101-09.ap.freescale.net> <cbd6490459b9fd68875fec4a7c7de073.squirrel@www.codeaurora.org> <20120320094031.GI3852@pengutronix.de> <20120320141811.GF32469@S2101-09.ap.freescale.net> <20120320181050.GN3852@pengutronix.de> <4F68E34A.70207@codeaurora.org> <20120320231242.GP3852@pengutronix.de> <CAJOA=zOGTW7OqACWgJQW6HSPLVev+apdNhv4vNXjHTcp=7N+uQ@mail.gmail.com> <4F694484.1030706@codeaurora.org> <4F714397.6080608@codeaurora.org> <CAJOA=zOq=kYfZUEnnQT_D4w=Kpp5n7R=k9oOCrxF59P5W-nw-w@mail.gmail.com> <4F7E4752.4020007@codeaurora.org> <CAJOA=zMEN_im3-T+_uXB_mTu842o_fRkr9-7h=X18fKBoH46aQ@mail.gmail.com>
In-Reply-To: <CAJOA=zMEN_im3-T+_uXB_mTu842o_fRkr9-7h=X18fKBoH46aQ@mail.gmail.com>
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On 04/11/2012 10:59 AM, Turquette, Mike wrote:
> On Thu, Apr 5, 2012 at 6:30 PM, Saravana Kannan<skannan@codeaurora.org>  wrote:
>> (*nudge*) (*nudge*) again :-)
>>
>> Sorry to keep nudging you on this often. The longer we wait for this, the
>> more churn it will cause later on. That's why I'm being persistent on this.
>> Also, once this goes in, I can start working on upstreaming MSM clock
>> support.

<SNIP>

> TL;DR: I think a combination of your change to expose the
> not-so-private parts of struct clk into struct clk_hw are OK and have
> real benefits for the clk-provider.h code.  However we need to
> implement it such that all the statically initialized data can be
> __initdata.

Sounds like a reasonable compromise.

> My only concern with this series is that platform clock code will
> access struct clk_hw members without the appropriate lock held (namely
> prepare_lock).  I'm a bit worried that there might be a case where
> some clock code access clk_hw->name when clk_hw has somehow been
> destroyed/altered (e.g. if clk_put every finally gets implemented...).
>   Besides clk_put are there any real instances where this might happen?

This problem is true for any struct/field marked as __init_data. So, I 
don't think this is a real problem. If someone is stupid enough to mark 
their data as __init_data and access them later, then there is not much 
we can do. Also, I believe the compiler throws out some warning when you 
try to access __init_data from non-init code.

> I'll be pushing my fixes branch out to the list soon.  Do you want to
> rebase this change on top of it taking into account the __initdata
> bits?

I thought it might be easier for you to base your changes on top of my 
patch. But I can try to rebase mine on top of your changes. Hopefully 
your fixes aren't crazy big/complex.

This is a busy week for me at work. I will try to send a patch in a day 
or two.

Thanks,
Saravana

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

From mboxrd@z Thu Jan  1 00:00:00 1970
From: skannan@codeaurora.org (Saravana Kannan)
Date: Wed, 11 Apr 2012 12:57:44 -0700
Subject: [PATCH 2/2] clk: Move init fields from clk to clk_hw
In-Reply-To: <CAJOA=zMEN_im3-T+_uXB_mTu842o_fRkr9-7h=X18fKBoH46aQ@mail.gmail.com>
References: <CAJOA=zN2cSSpM92oRnW0RyU_ZzyoQ=jthc-fAkf-P3z37uWt7w@mail.gmail.com>
 <1332214706-675-1-git-send-email-skannan@codeaurora.org>
 <1332214706-675-2-git-send-email-skannan@codeaurora.org>
 <20120320072018.GC32469@S2101-09.ap.freescale.net>
 <cbd6490459b9fd68875fec4a7c7de073.squirrel@www.codeaurora.org>
 <20120320094031.GI3852@pengutronix.de>
 <20120320141811.GF32469@S2101-09.ap.freescale.net>
 <20120320181050.GN3852@pengutronix.de> <4F68E34A.70207@codeaurora.org>
 <20120320231242.GP3852@pengutronix.de>
 <CAJOA=zOGTW7OqACWgJQW6HSPLVev+apdNhv4vNXjHTcp=7N+uQ@mail.gmail.com>
 <4F694484.1030706@codeaurora.org> <4F714397.6080608@codeaurora.org>
 <CAJOA=zOq=kYfZUEnnQT_D4w=Kpp5n7R=k9oOCrxF59P5W-nw-w@mail.gmail.com>
 <4F7E4752.4020007@codeaurora.org>
 <CAJOA=zMEN_im3-T+_uXB_mTu842o_fRkr9-7h=X18fKBoH46aQ@mail.gmail.com>
Message-ID: <4F85E238.9050102@codeaurora.org>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 04/11/2012 10:59 AM, Turquette, Mike wrote:
> On Thu, Apr 5, 2012 at 6:30 PM, Saravana Kannan<skannan@codeaurora.org>  wrote:
>> (*nudge*) (*nudge*) again :-)
>>
>> Sorry to keep nudging you on this often. The longer we wait for this, the
>> more churn it will cause later on. That's why I'm being persistent on this.
>> Also, once this goes in, I can start working on upstreaming MSM clock
>> support.

<SNIP>

> TL;DR: I think a combination of your change to expose the
> not-so-private parts of struct clk into struct clk_hw are OK and have
> real benefits for the clk-provider.h code.  However we need to
> implement it such that all the statically initialized data can be
> __initdata.

Sounds like a reasonable compromise.

> My only concern with this series is that platform clock code will
> access struct clk_hw members without the appropriate lock held (namely
> prepare_lock).  I'm a bit worried that there might be a case where
> some clock code access clk_hw->name when clk_hw has somehow been
> destroyed/altered (e.g. if clk_put every finally gets implemented...).
>   Besides clk_put are there any real instances where this might happen?

This problem is true for any struct/field marked as __init_data. So, I 
don't think this is a real problem. If someone is stupid enough to mark 
their data as __init_data and access them later, then there is not much 
we can do. Also, I believe the compiler throws out some warning when you 
try to access __init_data from non-init code.

> I'll be pushing my fixes branch out to the list soon.  Do you want to
> rebase this change on top of it taking into account the __initdata
> bits?

I thought it might be easier for you to base your changes on top of my 
patch. But I can try to rebase mine on top of your changes. Hopefully 
your fixes aren't crazy big/complex.

This is a busy week for me at work. I will try to send a patch in a day 
or two.

Thanks,
Saravana

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.