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

Leonardo Bras
2020-08-27T21:24:13Z

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@gmail.com>
> > ---
> > 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@ozlabs.ru>

Thank you!