From mboxrd@z Thu Jan  1 00:00:00 1970
From: jay.aurabind@gmail.com (Jay Aurabind)
Date: Fri, 9 May 2014 17:43:05 +0530
Subject: large frame size warning when compiling
In-Reply-To: <536B7AC0.1010507@posteo.de>
References: <20140507163608.GA6068@gmail.com>
 <536B7AC0.1010507@posteo.de>
Message-ID: <20140509121303.GB6218@gmail.com>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

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.
> > 
> > 
> > ---
> >  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);
> > 
> > 
> > 
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> > 
>