merge branch lineage-20 into t13.0t13.0

https: //github.com/LineageOS/android_kernel_google_redbull
Change-Id: I4a450eb794cc99abf711ad3b5b82946092be84ba

1 files changed, 6 insertions, 25 deletions

diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index c431ca81dad5..5779c1bc6f44 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -37,7 +37,6 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	int ret = 0;
-	int err;
 	int locked;
 
 	if (nr_frames == 0)
@@ -74,32 +73,14 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
 		vec->is_pfns = false;
 		ret = get_user_pages_locked(start, nr_frames,
 			gup_flags, (struct page **)(vec->ptrs), &locked);
-		goto out;
+		if (likely(ret > 0))
+			goto out;
 	}
 
-	vec->got_ref = false;
-	vec->is_pfns = true;
-	do {
-		unsigned long *nums = frame_vector_pfns(vec);
-
-		while (ret < nr_frames && start + PAGE_SIZE <= vma->vm_end) {
-			err = follow_pfn(vma, start, &nums[ret]);
-			if (err) {
-				if (ret == 0)
-					ret = err;
-				goto out;
-			}
-			start += PAGE_SIZE;
-			ret++;
-		}
-		/*
-		 * We stop if we have enough pages or if VMA doesn't completely
-		 * cover the tail page.
-		 */
-		if (ret >= nr_frames || start < vma->vm_end)
-			break;
-		vma = find_vma_intersection(mm, start, start + 1);
-	} while (vma && vma->vm_flags & (VM_IO | VM_PFNMAP));
+	/* This used to (racily) return non-refcounted pfns. Let people know */
+	WARN_ONCE(1, "get_vaddr_frames() cannot follow VM_IO mapping");
+	vec->nr_frames = 0;
+
 out:
 	if (locked)
 		up_read(&mm->mmap_sem);