From: skannan@codeaurora•org (Saravana Kannan)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/2] clk: Fix error handling in fixed clock hardware type register fn
Date: Tue, 20 Mar 2012 19:32:56 -0700 [thread overview]
Message-ID: <4F693DD8.7070305@codeaurora.org> (raw)
In-Reply-To: <CAJOA=zO=wp9oyuBZONk2oCRYdWU1c4qanKJik-8-sFg51p27MQ@mail.gmail.com>
On 03/20/2012 05:13 PM, Turquette, Mike wrote:
> On Tue, Mar 20, 2012 at 12:46 AM, Saravana Kannan
> <skannan@codeaurora•org> wrote:
>> On Tue, March 20, 2012 12:19 am, Sascha Hauer wrote:
>>> On Mon, Mar 19, 2012 at 08:38:25PM -0700, Saravana Kannan wrote:
>>>> If memory allocation for the parents array or the parent string fails,
>>>> then
>>>> fail the registration immediately instead of calling clk_register and
>>>> hoping it fails there.
>>>>
>>>> Return -ENOMEM on failure.
>>>>
>>>> Signed-off-by: Saravana Kannan<skannan@codeaurora•org>
>>>> Cc: Mike Turquette<mturquette@linaro•org>
>>>> Cc: Andrew Lunn<andrew@lunn•ch>
>>>> Cc: Rob Herring<rob.herring@calxeda•com>
>>>> Cc: Russell King<linux@arm•linux.org.uk>
>>>> Cc: Jeremy Kerr<jeremy.kerr@canonical•com>
>>>> Cc: Thomas Gleixner<tglx@linutronix•de>
>>>> Cc: Arnd Bergman<arnd.bergmann@linaro•org>
>>>> Cc: Paul Walmsley<paul@pwsan•com>
>>>> Cc: Shawn Guo<shawn.guo@freescale•com>
>>>> Cc: Sascha Hauer<s.hauer@pengutronix•de>
>>>> Cc: Jamie Iles<jamie@jamieiles•com>
>>>> Cc: Richard Zhao<richard.zhao@linaro•org>
>>>> Cc: Saravana Kannan<skannan@codeaurora•org>
>>>> Cc: Magnus Damm<magnus.damm@gmail•com>
>>>> Cc: Mark Brown<broonie@opensource•wolfsonmicro.com>
>>>> Cc: Linus Walleij<linus.walleij@stericsson•com>
>>>> Cc: Stephen Boyd<sboyd@codeaurora•org>
>>>> Cc: Amit Kucheria<amit.kucheria@linaro•org>
>>>> Cc: Deepak Saxena<dsaxena@linaro•org>
>>>> Cc: Grant Likely<grant.likely@secretlab•ca>
>>>> ---
>>>> There are still some memory free issues when clk_register() fails, but I
>>>> will
>>>> fix it when I fixed the other register() fns to return ENOMEM of alloc
>>>> failure instead of a NULL.
>>>>
>>>> drivers/clk/clk-fixed-rate.c | 10 +++++++---
>>>> 1 files changed, 7 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/clk/clk-fixed-rate.c b/drivers/clk/clk-fixed-rate.c
>>>> index 90c79fb..6423ae9 100644
>>>> --- a/drivers/clk/clk-fixed-rate.c
>>>> +++ b/drivers/clk/clk-fixed-rate.c
>>>> @@ -61,22 +61,26 @@ struct clk *clk_register_fixed_rate(struct device
>>>> *dev, const char *name,
>>>> parent_names = kmalloc(sizeof(char *), GFP_KERNEL);
>>>>
>>>> if (! parent_names)
>>>> - goto out;
>>>> + goto fail_ptr;
>>>>
>>>> len = sizeof(char) * strlen(parent_name);
>>>>
>>>> parent_names[0] = kmalloc(len, GFP_KERNEL);
>>>>
>>>> if (!parent_names[0])
>>>> - goto out;
>>>> + goto fail_str;
>>>>
>>>> strncpy(parent_names[0], parent_name, len);
>>>> }
>>>
>>> It's easier to add a char *parent to struct clk_fixed and pass it to
>>> clk_register with&fixed->parent. This saves you a kmalloc call and
>>> makes the error path simpler. It's the same way already done in the
>>> divider.
>
> I thought I had done this for v7... hmm looks like one got left out.
> I'll line up a patch to get it in sync with the others as part of my
> fixes.
>
>> I thought about that since I saw the same was done for gated and divider
>> (I think). Here is my guess at Mike's reasoning for this:
>>
>> Gated and divider clocks have to have a parent. There's nothing to gate
>> otherwise. But fixed rate clocks might not have a parent. It could be XO's
>> or PLLs running off of always on XOs not controlled by the SoC. So, it's
>> arguable to not have a parent. I don't have a strong opinion on this --
>> since Mike took the time to write it, it left it to his subjective
>> preference.
>
> I appreciate the thoughtfulness. Re-using the same type of mechanism
> as the divider and gate clocks will still allow the fixed-rate clock
> to be parentless, and it makes for cleaner code, one less allocation
> and lines up with how the other single-parent basic clocks are done,
> so I'll take that method in instead of your patch.
No problem, go for it.
>
>> I sent this patch first since it was around the place I was cleaning up. I
>> didn't want to actually just shuffle around a bug. As I mentioned, this
>> patch still leaves a bug open -- what if clk_register() fails. I plan to
>> fix that once my two patches are picked up (hopefully).
>
> Do you still find it useful to return -ENOMEM from the registration
> function instead of a NULL clock? I'm always worried that people
> don't check for error codes on pointers in their platform code and
> only check for NULL...
The last discussion I remember, NULL was considered a valid clock. So, I
think on error, we shouldn't ever return NULL when the return type is
struct clk *.
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.
next prev parent reply other threads:[~2012-03-21 2:32 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-16 6:11 [PATCH v7 0/3] common clk framework Mike Turquette
2012-03-16 6:11 ` [PATCH v7 1/3] Documentation: common clk API Mike Turquette
2012-03-16 8:25 ` Linus Walleij
2012-03-16 10:29 ` Thomas Gleixner
2012-03-16 11:14 ` Amit Kucheria
2012-03-16 12:18 ` Arnd Bergmann
2012-03-16 20:57 ` Arnd Bergmann
2012-03-16 21:40 ` Turquette, Mike
2012-03-16 21:50 ` Nicolas Pitre
2012-03-16 22:21 ` Paul Walmsley
2012-03-16 22:33 ` Turquette, Mike
2012-03-17 9:05 ` Arnd Bergmann
2012-03-17 18:02 ` Turquette, Mike
2012-03-17 18:33 ` Arnd Bergmann
2012-03-17 20:29 ` Sascha Hauer
2012-03-17 21:13 ` Arnd Bergmann
2012-03-20 23:40 ` Paul Walmsley
2012-03-21 8:59 ` Arnd Bergmann
2012-03-16 23:47 ` Sascha Hauer
2012-03-17 0:54 ` Rob Herring
2012-03-17 3:38 ` Saravana Kannan
2012-03-20 23:31 ` Paul Walmsley
2012-03-21 3:15 ` Nicolas Pitre
2012-03-21 3:26 ` Saravana Kannan
2012-03-21 7:44 ` Paul Walmsley
2012-03-21 9:10 ` Sascha Hauer
2012-03-21 18:38 ` Saravana Kannan
2012-03-21 19:07 ` Mark Brown
2012-03-21 19:33 ` Tony Lindgren
2012-03-21 19:41 ` Saravana Kannan
2012-03-21 19:56 ` Mark Brown
2012-03-21 20:04 ` Saravana Kannan
2012-03-21 20:10 ` Mark Brown
2012-03-22 0:42 ` Russell King - ARM Linux
2012-03-21 7:30 ` Paul Walmsley
2012-03-21 13:23 ` Nicolas Pitre
2012-03-16 6:11 ` [PATCH v7 2/3] clk: introduce the common clock framework Mike Turquette
2012-03-17 3:28 ` Saravana Kannan
2012-03-19 18:56 ` Turquette, Mike
2012-03-19 19:13 ` Saravana Kannan
2012-03-19 19:33 ` Turquette, Mike
2012-03-19 19:49 ` Saravana Kannan
2012-03-20 3:38 ` [PATCH 1/2] clk: Fix error handling in fixed clock hardware type register fn Saravana Kannan
2012-03-20 3:38 ` [PATCH 2/2] clk: Move init fields from clk to clk_hw Saravana Kannan
2012-03-20 7:20 ` Shawn Guo
2012-03-20 7:54 ` Saravana Kannan
2012-03-20 8:13 ` Shawn Guo
2012-03-20 9:40 ` Sascha Hauer
2012-03-20 10:17 ` Saravana Kannan
2012-03-20 18:14 ` Sascha Hauer
2012-03-20 20:14 ` Saravana Kannan
2012-03-20 22:40 ` Sascha Hauer
2012-03-22 3:23 ` Shawn Guo
2012-03-20 14:18 ` Shawn Guo
2012-03-20 18:10 ` Sascha Hauer
2012-03-20 20:06 ` Saravana Kannan
2012-03-20 23:12 ` Sascha Hauer
2012-03-21 1:47 ` Turquette, Mike
2012-03-21 3:01 ` Saravana Kannan
2012-03-27 4:35 ` Saravana Kannan
2012-03-27 18:49 ` Turquette, Mike
2012-03-27 22:27 ` Saravana Kannan
2012-04-06 1:30 ` Saravana Kannan
2012-04-11 17:59 ` Turquette, Mike
2012-04-11 19:57 ` Saravana Kannan
2012-04-11 20:17 ` Turquette, Mike
2012-04-11 20:21 ` Saravana Kannan
2012-03-20 23:47 ` Paul Walmsley
2012-03-21 9:16 ` Sascha Hauer
2012-03-20 7:19 ` [PATCH 1/2] clk: Fix error handling in fixed clock hardware type register fn Sascha Hauer
2012-03-20 7:46 ` Saravana Kannan
2012-03-21 0:13 ` Turquette, Mike
2012-03-21 2:32 ` Saravana Kannan [this message]
2012-03-21 5:45 ` Turquette, Mike
2012-03-21 6:33 ` Saravana Kannan
2012-03-21 9:07 ` Russell King - ARM Linux
2012-03-21 19:56 ` Turquette, Mike
2012-03-18 13:46 ` [PATCH v7 2/3] clk: introduce the common clock framework Shawn Guo
2012-03-19 18:58 ` Turquette, Mike
2012-03-18 14:07 ` Shawn Guo
2012-03-19 19:00 ` Turquette, Mike
2012-03-19 11:22 ` Rajendra Nayak
2012-03-19 11:28 ` Sascha Hauer
2012-03-19 19:09 ` Turquette, Mike
2012-03-19 19:53 ` Turquette, Mike
2012-03-20 14:02 ` Shawn Guo
2012-03-20 17:46 ` Saravana Kannan
2012-03-20 23:53 ` Turquette, Mike
2012-03-21 3:10 ` Saravana Kannan
2012-03-23 21:33 ` Saravana Kannan
2012-03-23 21:39 ` Turquette, Mike
2012-03-23 21:51 ` Saravana Kannan
2012-03-23 22:12 ` Saravana Kannan
2012-03-23 22:32 ` Turquette, Mike
2012-03-23 23:04 ` Saravana Kannan
2012-03-23 23:28 ` Turquette, Mike
2012-03-28 3:06 ` Saravana Kannan
2012-03-28 17:08 ` Turquette, Mike
2012-03-28 22:25 ` Saravana Kannan
2012-03-28 23:49 ` Turquette, Mike
2012-03-20 23:46 ` Turquette, Mike
2012-03-21 5:46 ` Shawn Guo
2012-03-16 6:11 ` [PATCH v7 3/3] clk: basic clock hardware types Mike Turquette
2012-03-16 12:25 ` Richard Zhao
2012-03-16 16:51 ` Turquette, Mike
2012-03-16 10:57 ` [PATCH v7 0/3] common clk framework Sascha Hauer
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