mm/huge_memory: rename mmun_start to haddr in remove_migration_pmd

mmun_start indicates mmu_notifier start address but there's no mmu_notifier
stuff in remove_migration_pmd. This will make it hard to get the meaning of
mmun_start. Rename it to haddr to avoid confusing readers and also imporve
readability.

Link: https://lkml.kernel.org/r/20220704132201.14611-7-linmiaohe@huawei.comSigned-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/huge_memory.c

@@ -3180,7 +3180,7 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
 	struct vm_area_struct *vma = pvmw->vma;
 	struct mm_struct *mm = vma->vm_mm;
 	unsigned long address = pvmw->address;
-	unsigned long mmun_start = address & HPAGE_PMD_MASK;
+	unsigned long haddr = address & HPAGE_PMD_MASK;
 	pmd_t pmde;
 	swp_entry_t entry;
 
@@ -3203,12 +3203,12 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
 		if (!is_readable_migration_entry(entry))
 			rmap_flags |= RMAP_EXCLUSIVE;
 
-		page_add_anon_rmap(new, vma, mmun_start, rmap_flags);
+		page_add_anon_rmap(new, vma, haddr, rmap_flags);
 	} else {
 		page_add_file_rmap(new, vma, true);
 	}
 	VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new));
-	set_pmd_at(mm, mmun_start, pvmw->pmd, pmde);
+	set_pmd_at(mm, haddr, pvmw->pmd, pmde);
 
 	/* No need to invalidate - it was non-present before */
 	update_mmu_cache_pmd(vma, address, pvmw->pmd);