On 12/1/21 15:30, Liam Howlett wrote:
> From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
>
> Replace the O(n.log(n)) loop with an O(n) loop.
Not true?
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 14 +++++---------
> 1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> index 3173c9f9a040..39960973c130 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> @@ -425,12 +425,11 @@ static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
> static int
> probe_range(struct mm_struct *mm, unsigned long addr, unsigned long len)
> {
> - const unsigned long end = addr + len;
> + VMA_ITERATOR(vmi, mm, addr);
> struct vm_area_struct *vma;
> - int ret = -EFAULT;
>
> mmap_read_lock(mm);
> - for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
> + for_each_vma_range(vmi, vma, addr + len) {
> /* Check for holes, note that we also update the addr below */
> if (vma->vm_start > addr)
> break;
> @@ -438,16 +437,13 @@ probe_range(struct mm_struct *mm, unsigned long addr, unsigned long len)
> if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
> break;
>
> - if (vma->vm_end >= end) {
> - ret = 0;
> - break;
> - }
> -
> addr = vma->vm_end;
> }
> mmap_read_unlock(mm);
>
> - return ret;
> + if (vma)
> + return -EFAULT;
> + return 0;
> }
>
> /*
