Merge tag 'locking-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

a5b1a017 · Linus Torvalds <[email protected]> · 2024-03-11 18:33:03 -07:00

Pull locking updates from Ingo Molnar:

 - Micro-optimize local_xchg() and the rtmutex code on x86

 - Fix percpu-rwsem contention tracepoints

 - Simplify debugging Kconfig dependencies

 - Update/clarify the documentation of atomic primitives

 - Misc cleanups

* tag 'locking-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/rtmutex: Use try_cmpxchg_relaxed() in mark_rt_mutex_waiters()
  locking/x86: Implement local_xchg() using CMPXCHG without the LOCK prefix
  locking/percpu-rwsem: Trigger contention tracepoints only if contended
  locking/rwsem: Make DEBUG_RWSEMS and PREEMPT_RT mutually exclusive
  locking/rwsem: Clarify that RWSEM_READER_OWNED is just a hint
  locking/mutex: Simplify <linux/mutex.h>
  locking/qspinlock: Fix 'wait_early' set but not used warning
  locking/atomic: scripts: Clarify ordering of conditional atomics

Commit: a5b1a017cb76e4898dd62fcb97e8aee6a63b33b5
Parents: b0402403 · ce3576eb

Merge commit. Changes below are compared with the first parent: b0402403.

Changes

17 files changed · +154 −49

File	Status	Add	Del	Content
arch/x86/include/asm/local.h	modified	+14	−2	View file
include/linux/atomic/atomic-arch-fallback.h	modified	+37	−9	View file
include/linux/atomic/atomic-instrumented.h	modified	+55	−13	View file
include/linux/atomic/atomic-long.h	modified	+19	−5	View file
include/linux/mutex.h	modified	+2	−6	View file
kernel/locking/percpu-rwsem.c	modified	+8	−3	View file
kernel/locking/qspinlock_paravirt.h	modified	+1	−1	View file
kernel/locking/rtmutex.c	modified	+5	−4	View file
kernel/locking/rwsem.c	modified	+3	−3	View file
lib/Kconfig.debug	modified	+2	−2	View file
scripts/atomic/kerneldoc/add_unless	modified	+1	−0	View file
scripts/atomic/kerneldoc/cmpxchg	modified	+1	−0	View file
scripts/atomic/kerneldoc/dec_if_positive	modified	+1	−0	View file
scripts/atomic/kerneldoc/dec_unless_positive	modified	+1	−0	View file
scripts/atomic/kerneldoc/inc_not_zero	modified	+1	−0	View file
scripts/atomic/kerneldoc/inc_unless_negative	modified	+1	−0	View file
scripts/atomic/kerneldoc/try_cmpxchg	modified	+2	−1	View file

Only the first 600 diff lines are shown. Download the complete patch.

arch/x86/include/asm/local.h

View file

diff --git a/arch/x86/include/asm/local.h b/arch/x86/include/asm/local.h
index 73dba8b..59aa966 100644
--- a/arch/x86/include/asm/local.h
+++ b/arch/x86/include/asm/local.h
@@ -131,8 +131,20 @@ static inline bool local_try_cmpxchg(local_t *l, long *old, long new)
 				 (typeof(l->a.counter) *) old, new);
 }
 
-/* Always has a lock prefix */
-#define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))
+/*
+ * Implement local_xchg using CMPXCHG instruction without the LOCK prefix.
+ * XCHG is expensive due to the implied LOCK prefix.  The processor
+ * cannot prefetch cachelines if XCHG is used.
+ */
+static __always_inline long
+local_xchg(local_t *l, long n)
+{
+	long c = local_read(l);
+
+	do { } while (!local_try_cmpxchg(l, &c, n));
+
+	return c;
+}
 
 /**
  * local_add_unless - add unless the number is already a given value

include/linux/atomic/atomic-arch-fallback.h

View file

diff --git a/include/linux/atomic/atomic-arch-fallback.h b/include/linux/atomic/atomic-arch-fallback.h
index 5e95faa..956bcba 100644
--- a/include/linux/atomic/atomic-arch-fallback.h
+++ b/include/linux/atomic/atomic-arch-fallback.h
@@ -2005,6 +2005,7 @@ raw_atomic_xchg_relaxed(atomic_t *v, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_cmpxchg() elsewhere.
  *
@@ -2033,6 +2034,7 @@ raw_atomic_cmpxchg(atomic_t *v, int old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_cmpxchg_acquire() elsewhere.
  *
@@ -2061,6 +2063,7 @@ raw_atomic_cmpxchg_acquire(atomic_t *v, int old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_cmpxchg_release() elsewhere.
  *
@@ -2088,6 +2091,7 @@ raw_atomic_cmpxchg_release(atomic_t *v, int old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_cmpxchg_relaxed() elsewhere.
  *
@@ -2112,7 +2116,8 @@ raw_atomic_cmpxchg_relaxed(atomic_t *v, int old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_try_cmpxchg() elsewhere.
  *
@@ -2145,7 +2150,8 @@ raw_atomic_try_cmpxchg(atomic_t *v, int *old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_try_cmpxchg_acquire() elsewhere.
  *
@@ -2178,7 +2184,8 @@ raw_atomic_try_cmpxchg_acquire(atomic_t *v, int *old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_try_cmpxchg_release() elsewhere.
  *
@@ -2210,7 +2217,8 @@ raw_atomic_try_cmpxchg_release(atomic_t *v, int *old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_try_cmpxchg_relaxed() elsewhere.
  *
@@ -2403,6 +2411,7 @@ raw_atomic_add_negative_relaxed(int i, atomic_t *v)
  * @u: int value to compare with
  *
  * If (@v != @u), atomically updates @v to (@v + @a) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_fetch_add_unless() elsewhere.
  *
@@ -2432,6 +2441,7 @@ raw_atomic_fetch_add_unless(atomic_t *v, int a, int u)
  * @u: int value to compare with
  *
  * If (@v != @u), atomically updates @v to (@v + @a) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_add_unless() elsewhere.
  *
@@ -2452,6 +2462,7 @@ raw_atomic_add_unless(atomic_t *v, int a, int u)
  * @v: pointer to atomic_t
  *
  * If (@v != 0), atomically updates @v to (@v + 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_inc_not_zero() elsewhere.
  *
@@ -2472,6 +2483,7 @@ raw_atomic_inc_not_zero(atomic_t *v)
  * @v: pointer to atomic_t
  *
  * If (@v >= 0), atomically updates @v to (@v + 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_inc_unless_negative() elsewhere.
  *
@@ -2499,6 +2511,7 @@ raw_atomic_inc_unless_negative(atomic_t *v)
  * @v: pointer to atomic_t
  *
  * If (@v <= 0), atomically updates @v to (@v - 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_dec_unless_positive() elsewhere.
  *
@@ -2526,6 +2539,7 @@ raw_atomic_dec_unless_positive(atomic_t *v)
  * @v: pointer to atomic_t
  *
  * If (@v > 0), atomically updates @v to (@v - 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic_dec_if_positive() elsewhere.
  *
@@ -4117,6 +4131,7 @@ raw_atomic64_xchg_relaxed(atomic64_t *v, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_cmpxchg() elsewhere.
  *
@@ -4145,6 +4160,7 @@ raw_atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_cmpxchg_acquire() elsewhere.
  *
@@ -4173,6 +4189,7 @@ raw_atomic64_cmpxchg_acquire(atomic64_t *v, s64 old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_cmpxchg_release() elsewhere.
  *
@@ -4200,6 +4217,7 @@ raw_atomic64_cmpxchg_release(atomic64_t *v, s64 old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_cmpxchg_relaxed() elsewhere.
  *
@@ -4224,7 +4242,8 @@ raw_atomic64_cmpxchg_relaxed(atomic64_t *v, s64 old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_try_cmpxchg() elsewhere.
  *
@@ -4257,7 +4276,8 @@ raw_atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_try_cmpxchg_acquire() elsewhere.
  *
@@ -4290,7 +4310,8 @@ raw_atomic64_try_cmpxchg_acquire(atomic64_t *v, s64 *old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_try_cmpxchg_release() elsewhere.
  *
@@ -4322,7 +4343,8 @@ raw_atomic64_try_cmpxchg_release(atomic64_t *v, s64 *old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_try_cmpxchg_relaxed() elsewhere.
  *
@@ -4515,6 +4537,7 @@ raw_atomic64_add_negative_relaxed(s64 i, atomic64_t *v)
  * @u: s64 value to compare with
  *
  * If (@v != @u), atomically updates @v to (@v + @a) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_fetch_add_unless() elsewhere.
  *
@@ -4544,6 +4567,7 @@ raw_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
  * @u: s64 value to compare with
  *
  * If (@v != @u), atomically updates @v to (@v + @a) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_add_unless() elsewhere.
  *
@@ -4564,6 +4588,7 @@ raw_atomic64_add_unless(atomic64_t *v, s64 a, s64 u)
  * @v: pointer to atomic64_t
  *
  * If (@v != 0), atomically updates @v to (@v + 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_inc_not_zero() elsewhere.
  *
@@ -4584,6 +4609,7 @@ raw_atomic64_inc_not_zero(atomic64_t *v)
  * @v: pointer to atomic64_t
  *
  * If (@v >= 0), atomically updates @v to (@v + 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_inc_unless_negative() elsewhere.
  *
@@ -4611,6 +4637,7 @@ raw_atomic64_inc_unless_negative(atomic64_t *v)
  * @v: pointer to atomic64_t
  *
  * If (@v <= 0), atomically updates @v to (@v - 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_dec_unless_positive() elsewhere.
  *
@@ -4638,6 +4665,7 @@ raw_atomic64_dec_unless_positive(atomic64_t *v)
  * @v: pointer to atomic64_t
  *
  * If (@v > 0), atomically updates @v to (@v - 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Safe to use in noinstr code; prefer atomic64_dec_if_positive() elsewhere.
  *
@@ -4662,4 +4690,4 @@ raw_atomic64_dec_if_positive(atomic64_t *v)
 }
 
 #endif /* _LINUX_ATOMIC_FALLBACK_H */
-// eec048affea735b8464f58e6d96992101f8f85f1
+// 14850c0b0db20c62fdc78ccd1d42b98b88d76331

include/linux/atomic/atomic-instrumented.h

View file

diff --git a/include/linux/atomic/atomic-instrumented.h b/include/linux/atomic/atomic-instrumented.h
index 54d7bbe..debd487 100644
--- a/include/linux/atomic/atomic-instrumented.h
+++ b/include/linux/atomic/atomic-instrumented.h
@@ -1182,6 +1182,7 @@ atomic_xchg_relaxed(atomic_t *v, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_cmpxchg() there.
  *
@@ -1202,6 +1203,7 @@ atomic_cmpxchg(atomic_t *v, int old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_cmpxchg_acquire() there.
  *
@@ -1221,6 +1223,7 @@ atomic_cmpxchg_acquire(atomic_t *v, int old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_cmpxchg_release() there.
  *
@@ -1241,6 +1244,7 @@ atomic_cmpxchg_release(atomic_t *v, int old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_cmpxchg_relaxed() there.
  *
@@ -1260,7 +1264,8 @@ atomic_cmpxchg_relaxed(atomic_t *v, int old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_try_cmpxchg() there.
  *
@@ -1282,7 +1287,8 @@ atomic_try_cmpxchg(atomic_t *v, int *old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_try_cmpxchg_acquire() there.
  *
@@ -1303,7 +1309,8 @@ atomic_try_cmpxchg_acquire(atomic_t *v, int *old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_try_cmpxchg_release() there.
  *
@@ -1325,7 +1332,8 @@ atomic_try_cmpxchg_release(atomic_t *v, int *old, int new)
  * @new: int value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_try_cmpxchg_relaxed() there.
  *
@@ -1475,6 +1483,7 @@ atomic_add_negative_relaxed(int i, atomic_t *v)
  * @u: int value to compare with
  *
  * If (@v != @u), atomically updates @v to (@v + @a) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_fetch_add_unless() there.
  *
@@ -1495,6 +1504,7 @@ atomic_fetch_add_unless(atomic_t *v, int a, int u)
  * @u: int value to compare with
  *
  * If (@v != @u), atomically updates @v to (@v + @a) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_add_unless() there.
  *
@@ -1513,6 +1523,7 @@ atomic_add_unless(atomic_t *v, int a, int u)
  * @v: pointer to atomic_t
  *
  * If (@v != 0), atomically updates @v to (@v + 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_inc_not_zero() there.
  *
@@ -1531,6 +1542,7 @@ atomic_inc_not_zero(atomic_t *v)
  * @v: pointer to atomic_t
  *
  * If (@v >= 0), atomically updates @v to (@v + 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_inc_unless_negative() there.
  *
@@ -1549,6 +1561,7 @@ atomic_inc_unless_negative(atomic_t *v)
  * @v: pointer to atomic_t
  *
  * If (@v <= 0), atomically updates @v to (@v - 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_dec_unless_positive() there.
  *
@@ -1567,6 +1580,7 @@ atomic_dec_unless_positive(atomic_t *v)
  * @v: pointer to atomic_t
  *
  * If (@v > 0), atomically updates @v to (@v - 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_dec_if_positive() there.
  *
@@ -2746,6 +2760,7 @@ atomic64_xchg_relaxed(atomic64_t *v, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_cmpxchg() there.
  *
@@ -2766,6 +2781,7 @@ atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_cmpxchg_acquire() there.
  *
@@ -2785,6 +2801,7 @@ atomic64_cmpxchg_acquire(atomic64_t *v, s64 old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_cmpxchg_release() there.
  *
@@ -2805,6 +2822,7 @@ atomic64_cmpxchg_release(atomic64_t *v, s64 old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_cmpxchg_relaxed() there.
  *
@@ -2824,7 +2842,8 @@ atomic64_cmpxchg_relaxed(atomic64_t *v, s64 old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_try_cmpxchg() there.
  *
@@ -2846,7 +2865,8 @@ atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_try_cmpxchg_acquire() there.
  *
@@ -2867,7 +2887,8 @@ atomic64_try_cmpxchg_acquire(atomic64_t *v, s64 *old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_try_cmpxchg_release() there.
  *
@@ -2889,7 +2910,8 @@ atomic64_try_cmpxchg_release(atomic64_t *v, s64 *old, s64 new)
  * @new: s64 value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_try_cmpxchg_relaxed() there.
  *
@@ -3039,6 +3061,7 @@ atomic64_add_negative_relaxed(s64 i, atomic64_t *v)
  * @u: s64 value to compare with
  *
  * If (@v != @u), atomically updates @v to (@v + @a) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_fetch_add_unless() there.
  *
@@ -3059,6 +3082,7 @@ atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
  * @u: s64 value to compare with
  *
  * If (@v != @u), atomically updates @v to (@v + @a) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_add_unless() there.
  *
@@ -3077,6 +3101,7 @@ atomic64_add_unless(atomic64_t *v, s64 a, s64 u)
  * @v: pointer to atomic64_t
  *
  * If (@v != 0), atomically updates @v to (@v + 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_inc_not_zero() there.
  *
@@ -3095,6 +3120,7 @@ atomic64_inc_not_zero(atomic64_t *v)
  * @v: pointer to atomic64_t
  *
  * If (@v >= 0), atomically updates @v to (@v + 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_inc_unless_negative() there.
  *
@@ -3113,6 +3139,7 @@ atomic64_inc_unless_negative(atomic64_t *v)
  * @v: pointer to atomic64_t
  *
  * If (@v <= 0), atomically updates @v to (@v - 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_dec_unless_positive() there.
  *
@@ -3131,6 +3158,7 @@ atomic64_dec_unless_positive(atomic64_t *v)
  * @v: pointer to atomic64_t
  *
  * If (@v > 0), atomically updates @v to (@v - 1) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic64_dec_if_positive() there.
  *
@@ -4310,6 +4338,7 @@ atomic_long_xchg_relaxed(atomic_long_t *v, long new)
  * @new: long value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_long_cmpxchg() there.
  *
@@ -4330,6 +4359,7 @@ atomic_long_cmpxchg(atomic_long_t *v, long old, long new)
  * @new: long value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_long_cmpxchg_acquire() there.
  *
@@ -4349,6 +4379,7 @@ atomic_long_cmpxchg_acquire(atomic_long_t *v, long old, long new)
  * @new: long value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_long_cmpxchg_release() there.
  *
@@ -4369,6 +4400,7 @@ atomic_long_cmpxchg_release(atomic_long_t *v, long old, long new)
  * @new: long value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_long_cmpxchg_relaxed() there.
  *
@@ -4388,7 +4420,8 @@ atomic_long_cmpxchg_relaxed(atomic_long_t *v, long old, long new)
  * @new: long value to assign
  *
  * If (@v == @old), atomically updates @v to @new with full ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_long_try_cmpxchg() there.
  *
@@ -4410,7 +4443,8 @@ atomic_long_try_cmpxchg(atomic_long_t *v, long *old, long new)
  * @new: long value to assign
  *
  * If (@v == @old), atomically updates @v to @new with acquire ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_long_try_cmpxchg_acquire() there.
  *
@@ -4431,7 +4465,8 @@ atomic_long_try_cmpxchg_acquire(atomic_long_t *v, long *old, long new)
  * @new: long value to assign
  *
  * If (@v == @old), atomically updates @v to @new with release ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_long_try_cmpxchg_release() there.
  *
@@ -4453,7 +4488,8 @@ atomic_long_try_cmpxchg_release(atomic_long_t *v, long *old, long new)
  * @new: long value to assign
  *
  * If (@v == @old), atomically updates @v to @new with relaxed ordering.
- * Otherwise, updates @old to the current value of @v.
+ * Otherwise, @v is not modified, @old is updated to the current value of @v,
+ * and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_long_try_cmpxchg_relaxed() there.
  *
@@ -4603,6 +4639,7 @@ atomic_long_add_negative_relaxed(long i, atomic_long_t *v)
  * @u: long value to compare with
  *
  * If (@v != @u), atomically updates @v to (@v + @a) with full ordering.
+ * Otherwise, @v is not modified and relaxed ordering is provided.
  *
  * Unsafe to use in noinstr code; use raw_atomic_long_fetch_add_unless() there.