RE: [PATCH V7 1/3] genalloc:support memory-allocation with bytes-alignment to genalloc

[Zhao Qiang]

On Wed, 2015-09-02 at 08:38AM +0800, Wood Scott-B07421 wrote:
> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Wednesday, September 02, 2015 8:30 AM
> To: Zhao Qiang-B45475
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx;
> lauraa@xxxxxxxxxxxxxx; Xie Xiaobo-R63061; benh@xxxxxxxxxxxxxxxxxxx; Li
> Yang-Leo-R58472; paulus@xxxxxxxxx
> Subject: Re: [PATCH V7 1/3] genalloc:support memory-allocation with
> bytes-alignment to genalloc
> 
> On Mon, 2015-08-31 at 16:58 +0800, Zhao Qiang wrote:
> > Bytes alignment is required to manage some special RAM, so add
> > gen_pool_first_fit_align to genalloc, meanwhile add
> > gen_pool_alloc_data to pass data to gen_pool_first_fit_align(modify
> > gen_pool_alloc as a wrapper)
> >
> > Signed-off-by: Zhao Qiang <qiang.zhao@xxxxxxxxxxxxx>
> > ---
> > Changes for v6:
> >       - patches set v6 include a new patch because of using
> >       - genalloc to manage QE MURAM, patch 0001 is the new
> >       - patch, adding bytes alignment for allocation for use.
> > Changes for v7:
> >       - cpm muram also need to use genalloc to manage, it has
> >         a function to reserve a specific region of muram,
> >         add offset to genpool_data for start addr to be allocated.
> 
> This seems to be describing more than just the changes in this patch.
> What does also handling cpm have to do with this patch?  Are you adding
> support for reserving a specific region in this patch?  I don't see it,
> and in any case it should go in a different patch.

Yes, I added. The code below can support the function.
	offset_bit = (alignment->offset + (1UL << order) - 1) >> order;
      return bitmap_find_next_zero_area(map, size, start + offset_bit, nr,
                        align_mask);
CPM has an function cpm_muram_alloc_fixed, needing to allocate muram from a
Specific offset. So I add the code and add offset to struct data.
This patch is the first patch of this patch set, so I explain what changes about
Set v7 and why I add support for reserving a specific region in this patch.

If you really think a different patch needed, I can add a new patch to handle it.

> 
> > +/*
> > + *  gen_pool data descriptor for gen_pool_first_fit_align.
> > + */
> > +struct genpool_data_align {
> > +     int align;              /* alignment by bytes for starting
> address */
> > +     unsigned long offset;   /* the offset of allocation start addr*/
> > +};
> 
> The offset belongs on the caller side, not here.

So, how do I pass offset to gen_pool_alloc_data or pool->algo?

> 
> -Scott