Re: [PATCH v1 05/10] powerpc/pseries/iommu: Add iommu_pseries_alloc_table() helper

[Leonardo Bras]

On Mon, 2020-08-24 at 10:38 +1000, Alexey Kardashevskiy wrote:
> 
> On 18/08/2020 09:40, Leonardo Bras wrote:
> > Creates a helper to allow allocating a new iommu_table without the need
> > to reallocate the iommu_group.
> > 
> > This will be helpful for replacing the iommu_table for the new DMA window,
> > after we remove the old one with iommu_tce_table_put().
> > 
> > Signed-off-by: Leonardo Bras <leobras.c@xxxxxxxxx>
> > ---
> >  arch/powerpc/platforms/pseries/iommu.c | 25 ++++++++++++++-----------
> >  1 file changed, 14 insertions(+), 11 deletions(-)
> > 
> > diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> > index 8fe23b7dff3a..39617ce0ec83 100644
> > --- a/arch/powerpc/platforms/pseries/iommu.c
> > +++ b/arch/powerpc/platforms/pseries/iommu.c
> > @@ -53,28 +53,31 @@ enum {
> >  	DDW_EXT_QUERY_OUT_SIZE = 2
> >  };
> >  
> > -static struct iommu_table_group *iommu_pseries_alloc_group(int node)
> > +static struct iommu_table *iommu_pseries_alloc_table(int node)
> >  {
> > -	struct iommu_table_group *table_group;
> >  	struct iommu_table *tbl;
> >  
> > -	table_group = kzalloc_node(sizeof(struct iommu_table_group), GFP_KERNEL,
> > -			   node);
> > -	if (!table_group)
> > -		return NULL;
> > -
> >  	tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL, node);
> >  	if (!tbl)
> > -		goto free_group;
> > +		return NULL;
> >  
> >  	INIT_LIST_HEAD_RCU(&tbl->it_group_list);
> >  	kref_init(&tbl->it_kref);
> > +	return tbl;
> > +}
> >  
> > -	table_group->tables[0] = tbl;
> > +static struct iommu_table_group *iommu_pseries_alloc_group(int node)
> > +{
> > +	struct iommu_table_group *table_group;
> > +
> > +	table_group = kzalloc_node(sizeof(*table_group), GFP_KERNEL, node);
> 
> I'd prefer you did not make unrelated changes (sizeof(struct
> iommu_table_group) -> sizeof(*table_group)) so the diff stays shorter
> and easier to follow. You changed  sizeof(struct iommu_table_group) but
> not sizeof(struct iommu_table) and this confused me enough to spend more
> time than this straight forward change deserves.

Sorry, I will keep this in mind for future patches.
Thank you for the tip!

> 
> Not important in this case though so
> 
> Reviewed-by: Alexey Kardashevskiy <aik@xxxxxxxxx>

Thank you!