lkml.org 
[lkml]   [2015]   [Jun]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [kernel, v12, 17/34] powerpc/spapr: vfio: Switch from iommu_table to new iommu_table_group
Date
On Fri, 2015-05-06 at 06:35:09 UTC, Alexey Kardashevskiy wrote:
> So far one TCE table could only be used by one IOMMU group. However
> IODA2 hardware allows programming the same TCE table address to
> multiple PE allowing sharing tables.

...

> + pnv_pci_link_table_and_group(phb->hose->node, 0, tbl, &pe->table_group);
> + pnv_pci_link_table_and_group(phb->hose->node, 0, tbl, &pe->table_group);
> + pnv_pci_link_table_and_group(phb->hose->node, 0,
> + tbl, &phb->p5ioc2.table_group);

> +long pnv_pci_link_table_and_group(int node, int num,
> + struct iommu_table *tbl,
> + struct iommu_table_group *table_group)
> +{
> + struct iommu_table_group_link *tgl = NULL;
> +
> + BUG_ON(!tbl);
> + BUG_ON(!table_group);
> + BUG_ON(!table_group->group);
> +
> + tgl = kzalloc_node(sizeof(struct iommu_table_group_link), GFP_KERNEL,
> + node);
> + if (!tgl)
> + return -ENOMEM;
> +
> + tgl->table_group = table_group;
> + list_add_rcu(&tgl->next, &tbl->it_group_list);
> +
> + table_group->tables[num] = tbl;
> +
> + return 0;

I'm not a fan of the BUG_ONs here.

This routine is so important that you have to BUG_ON three times at the start,
yet you never check the return code if it fails? That doesn't make sense to me.

If anything this should be sufficient:

if (WARN_ON(!tbl || !table_group))
return -EINVAL;

cheers


\
 
 \ /
  Last update: 2015-06-10 10:01    [W:0.171 / U:3.272 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site