答复: [PATCH] drm/amdkfd: use vma_lookup() instead of find_vma()

From: tomorrow Wang (王德明)
Date: Mon Oct 17 2022 - 20:47:40 EST


Hi,
The function vma_lookup show below. Vma valid check is included in it. Or, What other questions do you have?

static inline
struct vm_area_struct *vma_lookup(struct mm_struct *mm, unsigned long addr)
{
struct vm_area_struct *vma = find_vma(mm, addr);

if (vma && addr < vma->vm_start)
vma = NULL;

return vma;
}


> from: Felix Kuehling <felix.kuehling@xxxxxxx>
> time: 2022年10月18日 3:35
> to: tomorrow Wang (王德明) <wangdeming@xxxxxxxxxx>;
> airlied@xxxxxxxxx; daniel@xxxxxxxx; alexander.deucher@xxxxxxx;
> christian.koenig@xxxxxxx; Xinhui.Pan@xxxxxxx
> linux-kernel@xxxxxxxxxxxxxxx
> sub: Re: [PATCH] drm/amdkfd: use vma_lookup() instead of find_vma()
>
>
> On 2022-10-06 22:48, Deming Wang wrote:
> > Using vma_lookup() verifies the start address is contained in the
> > found vma. This results in easier to read the code.
>
> Thank you for the patches. This and your other patch look good to me.
> However, you missed one use of find_vma in svm_range_is_valid. Is that an
> oversight or is there a reason why we need to use find_vma there?
>
> If you're going to respin it, you may also squash the two patches into one.
>
> Thanks,
> Felix
>
>
> >
> > Signed-off-by: Deming Wang <wangdeming@xxxxxxxxxx>
> > ---
> > drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 12 ++++++------
> > 1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > index 64fdf63093a0..cabcc2ca3c23 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> > @@ -1586,8 +1586,8 @@ static int svm_range_validate_and_map(struct
> mm_struct *mm,
> > unsigned long npages;
> > bool readonly;
> >
> > - vma = find_vma(mm, addr);
> > - if (!vma || addr < vma->vm_start) {
> > + vma = vma_lookup(mm, addr);
> > + if (!vma) {
> > r = -EFAULT;
> > goto unreserve_out;
> > }
> > @@ -2542,8 +2542,8 @@ svm_range_get_range_boundaries(struct
> kfd_process *p, int64_t addr,
> > struct interval_tree_node *node;
> > unsigned long start_limit, end_limit;
> >
> > - vma = find_vma(p->mm, addr << PAGE_SHIFT);
> > - if (!vma || (addr << PAGE_SHIFT) < vma->vm_start) {
> > + vma = vma_lookup(p->mm, addr << PAGE_SHIFT);
> > + if (!vma) {
> > pr_debug("VMA does not exist in address [0x%llx]\n", addr);
> > return -EFAULT;
> > }
> > @@ -2871,8 +2871,8 @@ svm_range_restore_pages(struct amdgpu_device
> *adev, unsigned int pasid,
> > /* __do_munmap removed VMA, return success as we are handling stale
> > * retry fault.
> > */
> > - vma = find_vma(mm, addr << PAGE_SHIFT);
> > - if (!vma || (addr << PAGE_SHIFT) < vma->vm_start) {
> > + vma = vma_lookup(mm, addr << PAGE_SHIFT);
> > + if (!vma) {
> > pr_debug("address 0x%llx VMA is removed\n", addr);
> > r = 0;
> > goto out_unlock_range;

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