[PATCH v1 10/16] mm/memory: use __zap_vma_range() in zap_vma_for_reaping()

[David Hildenbrand (Arm)]

Let's call __zap_vma_range() instead of unmap_page_range() to prepare
for further cleanups.

To keep the existing behavior, whereby we do not call uprobe_munmap()
which could block, add a new "reaping" member to zap_details and use it.

Likely we should handle the possible blocking in uprobe_munmap()
differently, but for now keep it unchanged.

Signed-off-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
---
 include/linux/mm.h |  1 +
 mm/memory.c        | 13 +++++++++----
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 21b67c203e62..4710f7c7495a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2800,6 +2800,7 @@ struct zap_details {
 	struct folio *single_folio;	/* Locked folio to be unmapped */
 	bool skip_cows;			/* Do not zap COWed private pages */
 	bool reclaim_pt;		/* Need reclaim page tables? */
+	bool reaping;			/* Reaping, do not block. */
 	zap_flags_t zap_flags;		/* Extra flags for zapping */
 };
 
diff --git a/mm/memory.c b/mm/memory.c
index 7d7c24c6917c..394b2e931974 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2079,14 +2079,18 @@ static void __zap_vma_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		unsigned long start, unsigned long end,
 		struct zap_details *details)
 {
+	const bool reaping = details && details->reaping;
+
 	VM_WARN_ON_ONCE(start >= end || !range_in_vma(vma, start, end));
 
-	if (vma->vm_file)
+	/* uprobe_munmap() might sleep, so skip it when reaping. */
+	if (vma->vm_file && !reaping)
 		uprobe_munmap(vma, start, end);
 
 	if (unlikely(is_vm_hugetlb_page(vma))) {
 		zap_flags_t zap_flags = details ? details->zap_flags : 0;
 
+		VM_WARN_ON_ONCE(reaping);
 		/*
 		 * vm_file will be NULL when we fail early while instantiating
 		 * a new mapping. In this case, no pages were mapped yet and
@@ -2111,11 +2115,12 @@ static void __zap_vma_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
  */
 int zap_vma_for_reaping(struct vm_area_struct *vma)
 {
+	struct zap_details details = {
+		.reaping = true,
+	};
 	struct mmu_notifier_range range;
 	struct mmu_gather tlb;
 
-	VM_WARN_ON_ONCE(is_vm_hugetlb_page(vma));
-
 	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm,
 				vma->vm_start, vma->vm_end);
 	tlb_gather_mmu(&tlb, vma->vm_mm);
@@ -2123,7 +2128,7 @@ int zap_vma_for_reaping(struct vm_area_struct *vma)
 		tlb_finish_mmu(&tlb);
 		return -EBUSY;
 	}
-	unmap_page_range(&tlb, vma, range.start, range.end, NULL);
+	__zap_vma_range(&tlb, vma, range.start, range.end, &details);
 	mmu_notifier_invalidate_range_end(&range);
 	tlb_finish_mmu(&tlb);
 	return 0;
-- 
2.43.0