Re: [PATCH 1/6] oom: Make find_lock_task_mm() sparse-aware

From: Greg KH
Date: Mon Feb 06 2012 - 14:20:01 EST


On Mon, Feb 06, 2012 at 10:59:09PM +0400, Anton Vorontsov wrote:
> On Mon, Feb 06, 2012 at 08:35:42AM -0800, Greg KH wrote:
> [...]
> > > -extern struct task_struct *find_lock_task_mm(struct task_struct *p);
> > > +extern struct task_struct *__find_lock_task_mm(struct task_struct *p);
> > > +
> > > +#define find_lock_task_mm(p) \
> > > +({ \
> > > + struct task_struct *__ret; \
> > > + \
> > > + __cond_lock(&(p)->alloc_lock, __ret = __find_lock_task_mm(p)); \
> > > + __ret; \
> > > +})
> >
> > Please use the proper "do...while" style thing here for multi-line,
> > complex #defines like the rest of the kernel does so that you don't end
> > up debugging horrible problems later.
>
> Unfortunately this isn't possible in this case. Unlike '({})' GCC
> extension, do-while statement does not evaluate to a value, i.e.
> 'x = do { 123; } while (0);' is illegal.

Ah, you are right, my bad, sorry about that.

greg k-h
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