[RFC PATCH v2 2/4] mm/damon/paddr: implement damon_folio_mkold()

[SeongJae Park]

damon_pa_mkold() receives a physical address, finds the folio covering
the address, and makes the folio as old.  Split the internal logic for
checking access to the given folio, for future reuse of the logic.
Also, change the name of the rmap walker from __damon_pa_mkold() to
damon_folio_mkold_one() for more consistent naming.

Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
 mm/damon/paddr.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index 25c3ba2a9eaf..310b803c6277 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -16,8 +16,8 @@
 #include "../internal.h"
 #include "ops-common.h"
 
-static bool __damon_pa_mkold(struct folio *folio, struct vm_area_struct *vma,
-		unsigned long addr, void *arg)
+static bool damon_folio_mkold_one(struct folio *folio,
+		struct vm_area_struct *vma, unsigned long addr, void *arg)
 {
 	DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0);
 
@@ -31,33 +31,38 @@ static bool __damon_pa_mkold(struct folio *folio, struct vm_area_struct *vma,
 	return true;
 }
 
-static void damon_pa_mkold(unsigned long paddr)
+static void damon_folio_mkold(struct folio *folio)
 {
-	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
 	struct rmap_walk_control rwc = {
-		.rmap_one = __damon_pa_mkold,
+		.rmap_one = damon_folio_mkold_one,
 		.anon_lock = folio_lock_anon_vma_read,
 	};
 	bool need_lock;
 
-	if (!folio)
-		return;
-
 	if (!folio_mapped(folio) || !folio_raw_mapping(folio)) {
 		folio_set_idle(folio);
-		goto out;
+		return;
 	}
 
 	need_lock = !folio_test_anon(folio) || folio_test_ksm(folio);
 	if (need_lock && !folio_trylock(folio))
-		goto out;
+		return;
 
 	rmap_walk(folio, &rwc);
 
 	if (need_lock)
 		folio_unlock(folio);
 
-out:
+}
+
+static void damon_pa_mkold(unsigned long paddr)
+{
+	struct folio *folio = damon_get_folio(PHYS_PFN(paddr));
+
+	if (!folio)
+		return;
+
+	damon_folio_mkold(folio);
 	folio_put(folio);
 }
 
-- 
2.39.2