i915: use the VMA iterator

Replace the linked list in probe_range() with the VMA iterator.

Link: https://lkml.kernel.org/r/20220906194824.2110408-65-Liam.Howlett@oracle.comSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/gpu/drm/i915/gem/i915_gem_userptr.c

@@ -426,12 +426,11 @@ 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;
@@ -439,16 +438,13 @@ 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;
 }
 
 /*