[dm-devel] [PATCH 4/7] dm: introduce dm_kvmalloc

[Mikulas Patocka]

On Mon, 6 Jul 2015, Vivek Goyal wrote:

> On Fri, Jul 03, 2015 at 04:59:54PM -0400, Mikulas Patocka wrote:
> [..]
> > Index: linux-4.1/drivers/md/dm-table.c
> > ===================================================================
> > --- linux-4.1.orig/drivers/md/dm-table.c	2015-07-02 19:21:16.000000000 +0200
> > +++ linux-4.1/drivers/md/dm-table.c	2015-07-02 19:28:18.000000000 +0200
> > @@ -131,6 +131,43 @@ static int setup_btree_index(unsigned in
> >  	return 0;
> >  }
> >  
> > +void *dm_kvmalloc_node(size_t size, gfp_t gfp, int node)
> > +{
> > +	void *p;
> > +	unsigned uninitialized_var(noio_flag);
> > +
> > +	/* vmalloc doesn't support no-wait allocations */
> > +	WARN_ON(!(gfp & __GFP_WAIT));
> > +
> 
> Should this WARN_ON() be moved after kmalloc(). This should be triggered
> only if we use vmalloc().
> 
> Thanks
> Vivek

I think not - it would just hide the problematic usage. Warning always is 
better than warning with some low probability when kmalloc fails.

Mikulas