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

[tomorrow Wang (王德明)]

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 at amd.com>
> time: 2022年10月18日 3:35
> to: tomorrow Wang (王德明) <wangdeming at inspur.com>;
> airlied at gmail.com; daniel at ffwll.ch; alexander.deucher at amd.com;
> christian.koenig at amd.com; Xinhui.Pan at amd.com
> linux-kernel at vger.kernel.org
> 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 at inspur.com>
> > ---
> >   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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