[PATCH v4 03/15] mm/ksm: convert process iterator to for_each_process_rculock

[Ye Liu <ye.liu@linux.dev>]

From: Ye Liu <liuye@kylinos.cn>

Replace the manual rcu_read_lock()/rcu_read_unlock() pair combined
with for_each_process() loop in mm/ksm.c with for_each_process_rculock(),
which scopes the RCU read lock to the loop body via scoped_guard(rcu).

No functional change.

Signed-off-by: Ye Liu <liuye@kylinos.cn>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: SJ Park <sj@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
---
 mm/ksm.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 49d48d1e0998..69d30e80a090 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -3280,8 +3280,7 @@ void collect_procs_ksm(const struct folio *folio, const struct page *page,
 		struct anon_vma *av = rmap_item->anon_vma;
 
 		anon_vma_lock_read(av);
-		rcu_read_lock();
-		for_each_process(tsk) {
+		for_each_process_rculock(tsk) {
 			struct anon_vma_chain *vmac;
 			const unsigned long addr = rmap_item->address & PAGE_MASK;
 			const unsigned long index = rmap_item->linear_page_index;
@@ -3298,7 +3297,6 @@ void collect_procs_ksm(const struct folio *folio, const struct page *page,
 				}
 			}
 		}
-		rcu_read_unlock();
 		anon_vma_unlock_read(av);
 	}
 }
-- 
2.25.1