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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-05-05 12:56:55 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-05-05 12:56:55 -0700 |
commit | b115d85a9584c98f9a7dec209d835462aa1adc09 (patch) | |
tree | 332af6e2fafef47b9dc9891282b422eb5dcc5f3f /arch/x86/include | |
parent | d5ed10bb80bb376501cb56015a47457647efaabf (diff) | |
parent | ec570320b09f76d52819e60abdccf372658216b6 (diff) | |
download | linux-stable-b115d85a9584c98f9a7dec209d835462aa1adc09.tar.gz linux-stable-b115d85a9584c98f9a7dec209d835462aa1adc09.tar.bz2 linux-stable-b115d85a9584c98f9a7dec209d835462aa1adc09.zip |
Merge tag 'locking-core-2023-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
- Introduce local{,64}_try_cmpxchg() - a slightly more optimal
primitive, which will be used in perf events ring-buffer code
- Simplify/modify rwsems on PREEMPT_RT, to address writer starvation
- Misc cleanups/fixes
* tag 'locking-core-2023-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/atomic: Correct (cmp)xchg() instrumentation
locking/x86: Define arch_try_cmpxchg_local()
locking/arch: Wire up local_try_cmpxchg()
locking/generic: Wire up local{,64}_try_cmpxchg()
locking/atomic: Add generic try_cmpxchg{,64}_local() support
locking/rwbase: Mitigate indefinite writer starvation
locking/arch: Rename all internal __xchg() names to __arch_xchg()
Diffstat (limited to 'arch/x86/include')
-rw-r--r-- | arch/x86/include/asm/cmpxchg.h | 6 | ||||
-rw-r--r-- | arch/x86/include/asm/local.h | 13 |
2 files changed, 17 insertions, 2 deletions
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h index 94fbe6ae7431..540573f515b7 100644 --- a/arch/x86/include/asm/cmpxchg.h +++ b/arch/x86/include/asm/cmpxchg.h @@ -221,9 +221,15 @@ extern void __add_wrong_size(void) #define __try_cmpxchg(ptr, pold, new, size) \ __raw_try_cmpxchg((ptr), (pold), (new), (size), LOCK_PREFIX) +#define __try_cmpxchg_local(ptr, pold, new, size) \ + __raw_try_cmpxchg((ptr), (pold), (new), (size), "") + #define arch_try_cmpxchg(ptr, pold, new) \ __try_cmpxchg((ptr), (pold), (new), sizeof(*(ptr))) +#define arch_try_cmpxchg_local(ptr, pold, new) \ + __try_cmpxchg_local((ptr), (pold), (new), sizeof(*(ptr))) + /* * xadd() adds "inc" to "*ptr" and atomically returns the previous * value of "*ptr". diff --git a/arch/x86/include/asm/local.h b/arch/x86/include/asm/local.h index 349a47acaa4a..56d4ef604b91 100644 --- a/arch/x86/include/asm/local.h +++ b/arch/x86/include/asm/local.h @@ -120,8 +120,17 @@ static inline long local_sub_return(long i, local_t *l) #define local_inc_return(l) (local_add_return(1, l)) #define local_dec_return(l) (local_sub_return(1, l)) -#define local_cmpxchg(l, o, n) \ - (cmpxchg_local(&((l)->a.counter), (o), (n))) +static inline long local_cmpxchg(local_t *l, long old, long new) +{ + return cmpxchg_local(&l->a.counter, old, new); +} + +static inline bool local_try_cmpxchg(local_t *l, long *old, long new) +{ + typeof(l->a.counter) *__old = (typeof(l->a.counter) *) old; + return try_cmpxchg_local(&l->a.counter, __old, new); +} + /* Always has a lock prefix */ #define local_xchg(l, n) (xchg(&((l)->a.counter), (n))) |