Alexey Kardashevskiy <a...@ozlabs.ru> writes: > In some situations the userspace memory context may live longer than > the userspace process itself so if we need to do proper memory context > cleanup, we better cache @mm and use it later when the process is gone > (@current or @current->mm are NULL). > > This changes mm_iommu_xxx API to receive mm_struct instead of using one > from @current. > > This is needed by the following patch to do proper cleanup in time. > This depends on "powerpc/powernv/ioda: Fix endianness when reading TCEs" > to do proper cleanup via tce_iommu_clear() patch. > > To keep API consistent, this replaces mm_context_t with mm_struct; > we stick to mm_struct as mm_iommu_adjust_locked_vm() helper needs > access to &mm->mmap_sem. > > This should cause no behavioral change.
Is this a theoretical bug, or do we hit it in practice? In other words, should I merge this as a fix for 4.8, or can it wait for 4.9 with the rest of the series? > Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> > --- > arch/powerpc/include/asm/mmu_context.h | 20 +++++++------ > arch/powerpc/kernel/setup-common.c | 2 +- > arch/powerpc/mm/mmu_context_book3s64.c | 4 +-- > arch/powerpc/mm/mmu_context_iommu.c | 54 > ++++++++++++++-------------------- > drivers/vfio/vfio_iommu_spapr_tce.c | 41 ++++++++++++++++---------- I'd need an ACK from Alex for that part. cheers
