Re: [PATCH 09/26] ARM: OMAP: dmtimer: Get rid of check for mem resource error

From: Joel Fernandes
Date: Wed May 07 2014 - 18:14:57 EST


On 05/07/2014 05:10 PM, Tony Lindgren wrote:
> * Joel Fernandes <joelf@xxxxxx> [140507 14:53]:
>> On 05/07/2014 10:24 AM, Tony Lindgren wrote:
>>> * Joel Fernandes <joelf@xxxxxx> [140424 14:44]:
>>>> The subsequent devm_ioremap_resource will catch it and print an error, let it
>>>> be checked there.
>>>>
>>>> Signed-off-by: Joel Fernandes <joelf@xxxxxx>
>>>> ---
>>>> arch/arm/plat-omap/dmtimer.c | 4 ----
>>>> 1 file changed, 4 deletions(-)
>>>>
>>>> diff --git a/arch/arm/plat-omap/dmtimer.c b/arch/arm/plat-omap/dmtimer.c
>>>> index 7e806f9..1fd30fa 100644
>>>> --- a/arch/arm/plat-omap/dmtimer.c
>>>> +++ b/arch/arm/plat-omap/dmtimer.c
>>>> @@ -810,10 +810,6 @@ static int omap_dm_timer_probe(struct platform_device *pdev)
>>>> }
>>>>
>>>> mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>> - if (unlikely(!mem)) {
>>>> - dev_err(dev, "%s: no memory resource.\n", __func__);
>>>> - return -ENODEV;
>>>> - }
>>>>
>>>> timer = devm_kzalloc(dev, sizeof(struct omap_dm_timer), GFP_KERNEL);
>>>> if (!timer) {
>>>
>>> We still need to return an error here and not try to continue though.
>>
>> We are returning an error if mem is NULL so the redundant check is
>> unnecessary:
>>
>> ...
>> timer->io_base = devm_ioremap_resource(dev, mem);
>> if (IS_ERR(timer->io_base))
>> return PTR_ERR(timer->io_base);
>
> Why would you want to even continue omap_dm_timer_probe()
> further and allocate memory if platform_get_resource() fails?
>

But its freed anyway on error. I just felt that extra LOC could be
removed. Ideally we should do something like


mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
io_base = devm_ioremap_resource(dev, mem);
if (IS_ERR(io_base))
return PTR_ERR(io_base);

timer = devm_kzalloc(dev, sizeof(struct omap_dm_timer), GFP_KERNEL);
if (!timer) {
...
}
timer->io_base = io_base;


That combines the platform_get_resource and devm_ioremap_resource error
paths into 1 path and avoids redundant checks.. I can do it this way, or
if you want drop the patch entirely, I'm OK with it both ways..

thanks,

-Joel

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