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authorJani Nikula <jani.nikula@intel.com>2024-08-01 13:06:09 +0300
committerJani Nikula <jani.nikula@intel.com>2024-08-01 13:06:09 +0300
commit3663e2c4bc45fcdc71931fcbfcbfbf9b71f55c83 (patch)
tree3927fa90c7faa89131fcf2e789ca9de97a65dc5f /include/linux/compiler.h
parent688c43dd6ca9e0cd0568868aefca5b041695c3f4 (diff)
parent8400291e289ee6b2bf9779ff1c83a291501f017b (diff)
Merge drm/drm-next into drm-intel-next
Sync with v6.11-rc1 in general, and specifically get the new BACKLIGHT_POWER_ constants for power states. Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Diffstat (limited to 'include/linux/compiler.h')
-rw-r--r--include/linux/compiler.h16
1 files changed, 11 insertions, 5 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 8c252e073bd8..2594553bb30b 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -194,16 +194,22 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
* This data_race() macro is useful for situations in which data races
* should be forgiven. One example is diagnostic code that accesses
* shared variables but is not a part of the core synchronization design.
+ * For example, if accesses to a given variable are protected by a lock,
+ * except for diagnostic code, then the accesses under the lock should
+ * be plain C-language accesses and those in the diagnostic code should
+ * use data_race(). This way, KCSAN will complain if buggy lockless
+ * accesses to that variable are introduced, even if the buggy accesses
+ * are protected by READ_ONCE() or WRITE_ONCE().
*
* This macro *does not* affect normal code generation, but is a hint
- * to tooling that data races here are to be ignored.
+ * to tooling that data races here are to be ignored. If the access must
+ * be atomic *and* KCSAN should ignore the access, use both data_race()
+ * and READ_ONCE(), for example, data_race(READ_ONCE(x)).
*/
#define data_race(expr) \
({ \
- __unqual_scalar_typeof(({ expr; })) __v = ({ \
- __kcsan_disable_current(); \
- expr; \
- }); \
+ __kcsan_disable_current(); \
+ __auto_type __v = (expr); \
__kcsan_enable_current(); \
__v; \
})