Re: [PATCH] memblock: fix memblock_is_region_memory()

[Tomi Valkeinen <tomi.valkeinen@nokia.com>]

On Wed, 2010-11-24 at 15:31 -0800, ext Andrew Morton wrote:
> On Mon,  8 Nov 2010 13:00:13 +0200
> Tomi Valkeinen <tomi.valkeinen@nokia.com> wrote:
> 
> > To: benh@kernel.crashing.org, yinghai@kernel.org
> 
> wakey wakey!
> 
> > memblock_is_region_memory() uses reserved memblocks to search for the
> > given region, while it should use the memory memblocks.
> > 
> > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
> > ---
> >  mm/memblock.c |    8 ++++----
> >  1 files changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/mm/memblock.c b/mm/memblock.c
> > index 400dc62..bdba245 100644
> > --- a/mm/memblock.c
> > +++ b/mm/memblock.c
> > @@ -683,13 +683,13 @@ int __init_memblock memblock_is_memory(phys_addr_t addr)
> >  
> >  int __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
> >  {
> > -	int idx = memblock_search(&memblock.reserved, base);
> > +	int idx = memblock_search(&memblock.memory, base);
> >  
> >  	if (idx == -1)
> >  		return 0;
> > -	return memblock.reserved.regions[idx].base <= base &&
> > -		(memblock.reserved.regions[idx].base +
> > -		 memblock.reserved.regions[idx].size) >= (base + size);
> > +	return memblock.memory.regions[idx].base <= base &&
> > +		(memblock.memory.regions[idx].base +
> > +		 memblock.memory.regions[idx].size) >= (base + size);
> >  }
> 
> What were the runtime effects of this problem?
> 
> afacit the only callers are a couple of obscure fbdev drivers.  Do you
> know of other callers?

I don't know any other callers.

I encountered the problem with OMAP's framebuffer ram allocation.
Normally the ram is allocated dynamically, and this function is not
called. However, if we want to pass the framebuffer from the bootloader
to the kernel (to retain the boot image), this function is used to check
the validity of the kernel parameters for the framebuffer ram area.

 Tomi