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

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Message-ID: <20251219181147.3404071-4-ben.horgan@arm.com>
Date: Fri, 19 Dec 2025 18:11:05 +0000
From: Ben Horgan <ben.horgan@....com>
To: ben.horgan@....com
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Subject: [PATCH v2 03/45] arm_mpam: Use non-atomic bitops when modifying feature bitmap

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@....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