[PATCH 6.12.y 2/4] mm/damon/core: add damos_filter->allow field

[Sasha Levin <sashal@kernel.org>]

From: SeongJae Park <sj@kernel.org>

[ Upstream commit fe6d7fdd62491524d11433b9ff8d3db5dde32700 ]

DAMOS filters work as only exclusive (reject) filters.  This makes it easy
to be confused, and restrictive at combining multiple filters for covering
various types of memory.

Add a field named 'allow' to damos_filter.  The field will be used to
indicate whether the filter should work for inclusion or exclusion.  To
keep the old behavior, set it as 'false' (work as exclusive filter) by
default, from damos_new_filter().

Following two commits will make the core and operations set layers, which
handles damos_filter objects, respect the field, respectively.

Link: https://lkml.kernel.org/r/20250109175126.57878-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 28ab2265e942 ("mm/damon/tests/core-kunit: handle alloc failres in damon_test_new_filter()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/damon.h | 4 +++-
 mm/damon/core.c       | 1 +
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 0078912823d2..0da1397cd719 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -328,7 +328,8 @@ enum damos_filter_type {
 /**
  * struct damos_filter - DAMOS action target memory filter.
  * @type:	Type of the target memory.
- * @matching:	If the @type-matching memory should be filtered out.
+ * @matching:	Whether this is for @type-matching memory.
+ * @allow:	Whether to include or exclude the @matching memory.
  * @memcg_id:	Memcg id of the question if @type is DAMOS_FILTER_MEMCG.
  * @addr_range:	Address range if @type is DAMOS_FILTER_TYPE_ADDR.
  * @target_idx:	Index of the &struct damon_target of
@@ -345,6 +346,7 @@ enum damos_filter_type {
 struct damos_filter {
 	enum damos_filter_type type;
 	bool matching;
+	bool allow;
 	union {
 		unsigned short memcg_id;
 		struct damon_addr_range addr_range;
diff --git a/mm/damon/core.c b/mm/damon/core.c
index ed2b75023181..17a9fe18c069 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -275,6 +275,7 @@ struct damos_filter *damos_new_filter(enum damos_filter_type type,
 		return NULL;
 	filter->type = type;
 	filter->matching = matching;
+	filter->allow = false;
 	INIT_LIST_HEAD(&filter->list);
 	return filter;
 }
-- 
2.51.0