Implement cleanup_target() callback for [f]vaddr, which calls put_pid()
for each target that will be destroyed.  Also remove redundant put_pid()
calls in core and sysfs, which was required to be done redundantly due
to the lack of such self cleanup in vaddr.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core.c  |  2 --
 mm/damon/sysfs.c | 10 ++--------
 mm/damon/vaddr.c |  6 ++++++
 3 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index ce1087b5436f..6d526c5263d3 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1099,8 +1099,6 @@ static int damon_commit_targets(
 		} else {
 			struct damos *s;
 
-			if (damon_target_has_pid(dst))
-				put_pid(dst_target->pid);
 			damon_destroy_target(dst_target, dst);
 			damon_for_each_scheme(s, dst) {
 				if (s->quota.charge_target_from == dst_target) {
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index f2f9f756f5a2..5eba6ac53939 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1298,13 +1298,9 @@ static int damon_sysfs_set_attrs(struct damon_ctx *ctx,
 static void damon_sysfs_destroy_targets(struct damon_ctx *ctx)
 {
 	struct damon_target *t, *next;
-	bool has_pid = damon_target_has_pid(ctx);
 
-	damon_for_each_target_safe(t, next, ctx) {
-		if (has_pid)
-			put_pid(t->pid);
+	damon_for_each_target_safe(t, next, ctx)
 		damon_destroy_target(t, ctx);
-	}
 }
 
 static int damon_sysfs_set_regions(struct damon_target *t,
@@ -1387,10 +1383,8 @@ static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
 	if (!damon_target_has_pid(ctx))
 		return;
 
-	damon_for_each_target_safe(t, next, ctx) {
-		put_pid(t->pid);
+	damon_for_each_target_safe(t, next, ctx)
 		damon_destroy_target(t, ctx);
-	}
 }
 
 /*
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 46554e49a478..5c992317ee4c 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -627,6 +627,11 @@ static bool damon_va_target_valid(struct damon_target *t)
 	return false;
 }
 
+static void damon_va_cleanup_target(struct damon_target *t)
+{
+	put_pid(t->pid);
+}
+
 #ifndef CONFIG_ADVISE_SYSCALLS
 static unsigned long damos_madvise(struct damon_target *target,
 		struct damon_region *r, int behavior)
@@ -711,6 +716,7 @@ static int __init damon_va_initcall(void)
 		.prepare_access_checks = damon_va_prepare_access_checks,
 		.check_accesses = damon_va_check_accesses,
 		.target_valid = damon_va_target_valid,
+		.cleanup_target = damon_va_cleanup_target,
 		.cleanup = NULL,
 		.apply_scheme = damon_va_apply_scheme,
 		.get_scheme_score = damon_va_scheme_score,
-- 
2.39.5

On Sun,  6 Jul 2025 13:00:14 -0700 SeongJae Park <sj@kernel.org> wrote:

> Implement cleanup_target() callback for [f]vaddr, which calls put_pid()
> for each target that will be destroyed.  Also remove redundant put_pid()
> calls in core and sysfs, which was required to be done redundantly due
> to the lack of such self cleanup in vaddr.
> 
> Signed-off-by: SeongJae Park <sj@kernel.org>
> ---
>  mm/damon/core.c  |  2 --
>  mm/damon/sysfs.c | 10 ++--------
>  mm/damon/vaddr.c |  6 ++++++
>  3 files changed, 8 insertions(+), 10 deletions(-)

This patch forgot removing put_pid() from DAMON sample modules.  I will add
below fixup on the next version.


Thanks,
SJ

[...]
---------------------- >8 --------------------------
diff --git a/samples/damon/prcl.c b/samples/damon/prcl.c
index d3215699a5f4..60a84fffed57 100644
--- a/samples/damon/prcl.c
+++ b/samples/damon/prcl.c
@@ -120,8 +120,6 @@ static void damon_sample_prcl_stop(void)
                damon_stop(&ctx, 1);
                damon_destroy_ctx(ctx);
        }
-       if (target_pidp)
-               put_pid(target_pidp);
 }

 static bool init_called;
diff --git a/samples/damon/wsse.c b/samples/damon/wsse.c
index fb24190d2fc0..82a014c53cec 100644
--- a/samples/damon/wsse.c
+++ b/samples/damon/wsse.c
@@ -100,8 +100,6 @@ static void damon_sample_wsse_stop(void)
                damon_stop(&ctx, 1);
                damon_destroy_ctx(ctx);
        }
-       if (target_pidp)
-               put_pid(target_pidp);
 }

 static bool init_called;