linux-kernel - [PATCH v8 1/3] mm/rmap: remove duplicated exit code in pagewalk loop

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Date: Fri, 14 Jun 2024 09:51:36 +0800
From: Lance Yang <ioworker0@...il.com>
To: akpm@...ux-foundation.org
Cc: willy@...radead.org,
	sj@...nel.org,
	baolin.wang@...ux.alibaba.com,
	maskray@...gle.com,
	ziy@...dia.com,
	ryan.roberts@....com,
	david@...hat.com,
	21cnbao@...il.com,
	mhocko@...e.com,
	fengwei.yin@...el.com,
	zokeefe@...gle.com,
	shy828301@...il.com,
	xiehuan09@...il.com,
	libang.li@...group.com,
	wangkefeng.wang@...wei.com,
	songmuchun@...edance.com,
	peterx@...hat.com,
	minchan@...nel.org,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Lance Yang <ioworker0@...il.com>,
	Barry Song <baohua@...nel.org>
Subject: [PATCH v8 1/3] mm/rmap: remove duplicated exit code in pagewalk loop

Introduce the labels walk_done and walk_abort as exit points to eliminate
duplicated exit code in the pagewalk loop.

Reviewed-by: Zi Yan <ziy@...dia.com>
Reviewed-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
Reviewed-by: David Hildenbrand <david@...hat.com>
Reviewed-by: Barry Song <baohua@...nel.org>
Signed-off-by: Lance Yang <ioworker0@...il.com>
---
 mm/rmap.c | 40 +++++++++++++++-------------------------
 1 file changed, 15 insertions(+), 25 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index ae250b2b4d55..2d778725e4f5 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1681,9 +1681,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 			/* Restore the mlock which got missed */
 			if (!folio_test_large(folio))
 				mlock_vma_folio(folio, vma);
-			page_vma_mapped_walk_done(&pvmw);
-			ret = false;
-			break;
+			goto walk_abort;
 		}
 
 		pfn = pte_pfn(ptep_get(pvmw.pte));
@@ -1721,11 +1719,8 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 			 */
 			if (!anon) {
 				VM_BUG_ON(!(flags & TTU_RMAP_LOCKED));
-				if (!hugetlb_vma_trylock_write(vma)) {
-					page_vma_mapped_walk_done(&pvmw);
-					ret = false;
-					break;
-				}
+				if (!hugetlb_vma_trylock_write(vma))
+					goto walk_abort;
 				if (huge_pmd_unshare(mm, vma, address, pvmw.pte)) {
 					hugetlb_vma_unlock_write(vma);
 					flush_tlb_range(vma,
@@ -1740,8 +1735,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 					 * actual page and drop map count
 					 * to zero.
 					 */
-					page_vma_mapped_walk_done(&pvmw);
-					break;
+					goto walk_done;
 				}
 				hugetlb_vma_unlock_write(vma);
 			}
@@ -1813,9 +1807,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 			if (unlikely(folio_test_swapbacked(folio) !=
 					folio_test_swapcache(folio))) {
 				WARN_ON_ONCE(1);
-				ret = false;
-				page_vma_mapped_walk_done(&pvmw);
-				break;
+				goto walk_abort;
 			}
 
 			/* MADV_FREE page check */
@@ -1854,23 +1846,17 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 				 */
 				set_pte_at(mm, address, pvmw.pte, pteval);
 				folio_set_swapbacked(folio);
-				ret = false;
-				page_vma_mapped_walk_done(&pvmw);
-				break;
+				goto walk_abort;
 			}
 
 			if (swap_duplicate(entry) < 0) {
 				set_pte_at(mm, address, pvmw.pte, pteval);
-				ret = false;
-				page_vma_mapped_walk_done(&pvmw);
-				break;
+				goto walk_abort;
 			}
 			if (arch_unmap_one(mm, vma, address, pteval) < 0) {
 				swap_free(entry);
 				set_pte_at(mm, address, pvmw.pte, pteval);
-				ret = false;
-				page_vma_mapped_walk_done(&pvmw);
-				break;
+				goto walk_abort;
 			}
 
 			/* See folio_try_share_anon_rmap(): clear PTE first. */
@@ -1878,9 +1864,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 			    folio_try_share_anon_rmap_pte(folio, subpage)) {
 				swap_free(entry);
 				set_pte_at(mm, address, pvmw.pte, pteval);
-				ret = false;
-				page_vma_mapped_walk_done(&pvmw);
-				break;
+				goto walk_abort;
 			}
 			if (list_empty(&mm->mmlist)) {
 				spin_lock(&mmlist_lock);
@@ -1920,6 +1904,12 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 		if (vma->vm_flags & VM_LOCKED)
 			mlock_drain_local();
 		folio_put(folio);
+		continue;
+walk_abort:
+		ret = false;
+walk_done:
+		page_vma_mapped_walk_done(&pvmw);
+		break;
 	}
 
 	mmu_notifier_invalidate_range_end(&range);
-- 
2.33.1