Let's inline it into the single caller to reduce the number of confusing
unmap/zap helpers.

Get rid of the unnecessary BUG_ON().

Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
---
 mm/memory.c | 32 ++++++++++++--------------------
 1 file changed, 12 insertions(+), 20 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 394b2e931974..1c0bcdfc73b7 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2056,25 +2056,6 @@ static inline unsigned long zap_p4d_range(struct mmu_gather *tlb,
 	return addr;
 }
 
-static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
-		unsigned long addr, unsigned long end,
-		struct zap_details *details)
-{
-	pgd_t *pgd;
-	unsigned long next;
-
-	BUG_ON(addr >= end);
-	tlb_start_vma(tlb, vma);
-	pgd = pgd_offset(vma->vm_mm, addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		if (pgd_none_or_clear_bad(pgd))
-			continue;
-		next = zap_p4d_range(tlb, vma, pgd, addr, next, details);
-	} while (pgd++, addr = next, addr != end);
-	tlb_end_vma(tlb, vma);
-}
-
 static void __zap_vma_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		unsigned long start, unsigned long end,
 		struct zap_details *details)
@@ -2100,7 +2081,18 @@ static void __zap_vma_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			return;
 		__unmap_hugepage_range(tlb, vma, start, end, NULL, zap_flags);
 	} else {
-		unmap_page_range(tlb, vma, start, end, details);
+		unsigned long next, cur = start;
+		pgd_t *pgd;
+
+		tlb_start_vma(tlb, vma);
+		pgd = pgd_offset(vma->vm_mm, cur);
+		do {
+			next = pgd_addr_end(cur, end);
+			if (pgd_none_or_clear_bad(pgd))
+				continue;
+			next = zap_p4d_range(tlb, vma, pgd, cur, next, details);
+		} while (pgd++, cur = next, cur != end);
+		tlb_end_vma(tlb, vma);
 	}
 }
 
-- 
2.43.0