On Mon, Oct 15, 2018 at 08:24:15PM +1100, Alexey Kardashevskiy wrote:
> Since we are going to have 2 different preregistering helpers, let's
> make it clear that mm_iommu_new() is only for the normal (i.e. not device)
> memory and for existing areas mm_iommu_get() should be used instead.
>
> Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
I think the idea is sensible. However (and, yes, this is really an
existing bug) - shouldn't we check for a request to add anything
overlapping with an existing region, not just one that exactly
matches?
> ---
> arch/powerpc/mm/mmu_context_iommu.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c
> index a8c4a3c..839dbce 100644
> --- a/arch/powerpc/mm/mmu_context_iommu.c
> +++ b/arch/powerpc/mm/mmu_context_iommu.c
> @@ -141,8 +141,7 @@ long mm_iommu_new(struct mm_struct *mm, unsigned long ua, unsigned long entries,
> list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list,
> next) {
> if ((mem->ua == ua) && (mem->entries == entries)) {
> - ++mem->used;
> - *pmem = mem;
> + ret = -EBUSY;
> goto unlock_exit;
> }
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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