On Tue, 9 Aug 2016 14:43:00 +1000
Balbir Singh <bsinghar...@gmail.com> wrote:
> On 03/08/16 18:40, Alexey Kardashevskiy wrote:
> > -long mm_iommu_get(unsigned long ua, unsigned long entries,
> > +long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long
> > entries,
> > struct mm_iommu_table_group_mem_t **pmem)
> > {
> > struct mm_iommu_table_group_mem_t *mem;
> > long i, j, ret = 0, locked_entries = 0;
> > struct page *page = NULL;
> >
> > - if (!current || !current->mm)
> > - return -ESRCH; /* process exited */
>
> VM_BUG_ON(mm == NULL)?
> > @@ -128,10 +129,17 @@ static long tce_iommu_register_pages(struct
> > tce_container *container,
> > ((vaddr + size) < vaddr))
> > return -EINVAL;
> >
> > - ret = mm_iommu_get(vaddr, entries, &mem);
> > + if (!container->mm) {
> > + if (!current->mm)
> > + return -ESRCH; /* process exited */
>
> You may even want to check for PF_EXITING and ignore those tasks?
These are related to some of the questions I had about the patch.
But I think it makes sense just to take this approach as a minimal
bug fix without changing logic too much or adding BUG_ONs, and then
if we we can consider how iommu takes references to mm and uses it
(if anybody finds the time).
Thanks,
Nick
