On Friday 09 May 2014 05:43 PM, Jay Aurabind wrote:
> On Thu, May 08, 2014 at 02:38:24PM +0200, Martin Kepplinger wrote:
>> Am 2014-05-07 18:36, schrieb Jay Aurabind:
>>> Hello list, Time for a noob discussion,
>>>
>>> When I was building the kernel, I found a warning from drivers/mfd/abx500-core.c, that the Frame size is larger than 1024 bytes. Apparently the stack frame size can be changed from the config, but my question is, whether 1024 bytes low ? I am on an x86_64 (core i3).
>>>
>>> abx500-core.c had an object of struct device being allocated on stack. So
>>> dynamically allocating it makes the warning go away. Are there any
>>> implications on using dynamic allocation on this particular code? I
>>> mean, could there be some reason why the original developer went with static option ?
>> kmalloc may sleep and is therefore sometimes not recommended to be used.
>>
> Sure, but this code doesnt appear to be holding any locks. So it should
> be okay to call kmalloc here I guess.
You can use kmalloc even if you are holding a lock. Care must be taken
to pass GFP_ATOMIC flag to the kmalloc, so that it does not sleep.
>>>
>>> ---
>>> drivers/mfd/abx500-core.c | 8 +++++---
>>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/mfd/abx500-core.c b/drivers/mfd/abx500-core.c
>>> index f3a15aa..709a84f 100644
>>> --- a/drivers/mfd/abx500-core.c
>>> +++ b/drivers/mfd/abx500-core.c
>>> @@ -154,15 +154,17 @@ EXPORT_SYMBOL(abx500_startup_irq_enabled);
>>> void abx500_dump_all_banks(void)
>>> {
>>> struct abx500_ops *ops;
>>> - struct device dummy_child = {NULL};
>>> + struct device *dummy_child;
>>> struct abx500_device_entry *dev_entry;
>>>
>>> + dummy_child = kzalloc(sizeof(struct device),GFP_KERNEL);
>>> +
>>> list_for_each_entry(dev_entry, &abx500_list, list) {
>>> - dummy_child.parent = dev_entry->dev;
>>> + dummy_child->parent = dev_entry->dev;
>>> ops = &dev_entry->ops;
>>>
>>> if ((ops != NULL) && (ops->dump_all_banks != NULL))
>>> - ops->dump_all_banks(&dummy_child);
>>> + ops->dump_all_banks(dummy_child);
>>> }
>>> }
>>> EXPORT_SYMBOL(abx500_dump_all_banks);
>>>
>>>
>>>
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> Kernelnewbies@xxxxxxxxxxxxxxxxx
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@xxxxxxxxxxxxxxxxx
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
--
Paul Davies C,
CSE B.Tech. student,
Govt. Engineering College, Thrissur.
_______________________________________________
Kernelnewbies mailing list
Kernelnewbies@xxxxxxxxxxxxxxxxx
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
