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-rw-r--r--mm/pagewalk.c21
1 files changed, 13 insertions, 8 deletions
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 4c9a653..75c1f28 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -35,7 +35,7 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
do {
again:
next = pmd_addr_end(addr, end);
- if (pmd_none(*pmd)) {
+ if (pmd_none(*pmd) || !walk->vma) {
if (walk->pte_hole)
err = walk->pte_hole(addr, next, walk);
if (err)
@@ -165,9 +165,6 @@ static int walk_hugetlb_range(unsigned long addr, unsigned long end,
* or skip it via the returned value. Return 0 if we do walk over the
* current vma, and return 1 if we skip the vma. Negative values means
* error, where we abort the current walk.
- *
- * Default check (only VM_PFNMAP check for now) is used when the caller
- * doesn't define test_walk() callback.
*/
static int walk_page_test(unsigned long start, unsigned long end,
struct mm_walk *walk)
@@ -178,11 +175,19 @@ static int walk_page_test(unsigned long start, unsigned long end,
return walk->test_walk(start, end, walk);
/*
- * Do not walk over vma(VM_PFNMAP), because we have no valid struct
- * page backing a VM_PFNMAP range. See also commit a9ff785e4437.
+ * vma(VM_PFNMAP) doesn't have any valid struct pages behind VM_PFNMAP
+ * range, so we don't walk over it as we do for normal vmas. However,
+ * Some callers are interested in handling hole range and they don't
+ * want to just ignore any single address range. Such users certainly
+ * define their ->pte_hole() callbacks, so let's delegate them to handle
+ * vma(VM_PFNMAP).
*/
- if (vma->vm_flags & VM_PFNMAP)
- return 1;
+ if (vma->vm_flags & VM_PFNMAP) {
+ int err = 1;
+ if (walk->pte_hole)
+ err = walk->pte_hole(start, end, walk);
+ return err ? err : 1;
+ }
return 0;
}
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