Hi Russell,
On Thu, Mar 7, 2013 at 9:07 PM, Russell King - ARM Linux
<linux@xxxxxxxxxxxxxxxx> wrote:
> On Thu, Mar 07, 2013 at 04:28:00PM +0100, Sylwester Nawrocki wrote:
>> On 03/07/2013 05:13 AM, Amit Daniel Kachhap wrote:
>> > + dvfs_info->cpu_clk = devm_clk_get(dvfs_info->dev, "armclk");
>> > + if (IS_ERR_OR_NULL(dvfs_info->cpu_clk)) {
>>
>> devm_clk_get() return value needs to be checked with IS_ERR(),
>> not IS_ERR_OR_NULL().
>>
>> > + pr_err("Failed to get cpu clock\n");
>> > + ret = PTR_ERR(dvfs_info->cpu_clk);
>> > + goto err_free_table;
>
> Amit, to illustrate why this is wrong, consider this:
> 1. Set cpu_clk to NULL.
> 2. Realise IS_ERR_OR_NULL(NULL) is true.
> 3. What is the value of PTR_ERR(NULL) ?
> 4. What effect does that have when you jump to err_free_table ?
> 5. What value is returned from this function in that case ?
> 6. What does that return value mean to the driver core ?
Thanks for the detailed explaination. Usage of IS_ERR_OR_NULL is not
suitable here.
Thanks,
Amit D
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