[PATCH v2 03/45] arm_mpam: Use non-atomic bitops when modifying feature bitmap

Ben Horgan
2025-12-19T18:12:16Z

In the test__props_mismatch() kunit test we rely on the struct mpam_props
being packed to ensure memcmp doesn't consider packing. Making it packed
reduces the alignment of the features bitmap and so breaks a requirement
for the use of atomics. As we don't rely on the set/clear of these bits
being atomic, just make them non-atomic.

Signed-off-by: Ben Horgan <ben.horgan@arm.com>
---
drivers/resctrl/mpam_internal.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
index 17cdc3080d58..aaaf31ca9210 100644
--- a/drivers/resctrl/mpam_internal.h
+++ b/drivers/resctrl/mpam_internal.h
@@ -200,8 +200,8 @@ struct mpam_props {
} PACKED_FOR_KUNIT;

#define mpam_has_feature(_feat, x) test_bit(_feat, (x)->features)
-#define mpam_set_feature(_feat, x) set_bit(_feat, (x)->features)
-#define mpam_clear_feature(_feat, x) clear_bit(_feat, (x)->features)
+#define mpam_set_feature(_feat, x) __set_bit(_feat, (x)->features)
+#define mpam_clear_feature(_feat, x) __clear_bit(_feat, (x)->features)

/* The values for MSMON_CFG_MBWU_FLT.RWBW */
enum mon_filter_options {
--
2.43.0