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authorLinus Torvalds <torvalds@linux-foundation.org>2023-10-31 01:38:48 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2023-10-31 01:38:48 +0300
commit3cf3fabccb9dc821ffaec3ad6bf0cd6b278bd012 (patch)
tree76bf15f5939812608b8ea514c3c50fd1ac8acebb /lib
parent9cda4eb04a68aee4d795438917a4e958b2b2aa07 (diff)
parentc73801ae4f22b390228ebf471d55668e824198b6 (diff)
downloadlinux-3cf3fabccb9dc821ffaec3ad6bf0cd6b278bd012.tar.xz
Merge tag 'locking-core-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Info Molnar: "Futex improvements: - Add the 'futex2' syscall ABI, which is an attempt to get away from the multiplex syscall and adds a little room for extentions, while lifting some limitations. - Fix futex PI recursive rt_mutex waiter state bug - Fix inter-process shared futexes on no-MMU systems - Use folios instead of pages Micro-optimizations of locking primitives: - Improve arch_spin_value_unlocked() on asm-generic ticket spinlock architectures, to improve lockref code generation - Improve the x86-32 lockref_get_not_zero() main loop by adding build-time CMPXCHG8B support detection for the relevant lockref code, and by better interfacing the CMPXCHG8B assembly code with the compiler - Introduce arch_sync_try_cmpxchg() on x86 to improve sync_try_cmpxchg() code generation. Convert some sync_cmpxchg() users to sync_try_cmpxchg(). - Micro-optimize rcuref_put_slowpath() Locking debuggability improvements: - Improve CONFIG_DEBUG_RT_MUTEXES=y to have a fast-path as well - Enforce atomicity of sched_submit_work(), which is de-facto atomic but was un-enforced previously. - Extend <linux/cleanup.h>'s no_free_ptr() with __must_check semantics - Fix ww_mutex self-tests - Clean up const-propagation in <linux/seqlock.h> and simplify the API-instantiation macros a bit RT locking improvements: - Provide the rt_mutex_*_schedule() primitives/helpers and use them in the rtmutex code to avoid recursion vs. rtlock on the PI state. - Add nested blocking lockdep asserts to rt_mutex_lock(), rtlock_lock() and rwbase_read_lock() .. plus misc fixes & cleanups" * tag 'locking-core-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits) futex: Don't include process MM in futex key on no-MMU locking/seqlock: Fix grammar in comment alpha: Fix up new futex syscall numbers locking/seqlock: Propagate 'const' pointers within read-only methods, remove forced type casts locking/lockdep: Fix string sizing bug that triggers a format-truncation compiler-warning locking/seqlock: Change __seqprop() to return the function pointer locking/seqlock: Simplify SEQCOUNT_LOCKNAME() locking/atomics: Use atomic_try_cmpxchg_release() to micro-optimize rcuref_put_slowpath() locking/atomic, xen: Use sync_try_cmpxchg() instead of sync_cmpxchg() locking/atomic/x86: Introduce arch_sync_try_cmpxchg() locking/atomic: Add generic support for sync_try_cmpxchg() and its fallback locking/seqlock: Fix typo in comment futex/requeue: Remove unnecessary ‘NULL’ initialization from futex_proxy_trylock_atomic() locking/local, arch: Rewrite local_add_unless() as a static inline function locking/debug: Fix debugfs API return value checks to use IS_ERR() locking/ww_mutex/test: Make sure we bail out instead of livelock locking/ww_mutex/test: Fix potential workqueue corruption locking/ww_mutex/test: Use prng instead of rng to avoid hangs at bootup futex: Add sys_futex_requeue() futex: Add flags2 argument to futex_requeue() ...
Diffstat (limited to 'lib')
-rw-r--r--lib/rcuref.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/rcuref.c b/lib/rcuref.c
index 5ec00a4a64d1..97f300eca927 100644
--- a/lib/rcuref.c
+++ b/lib/rcuref.c
@@ -248,7 +248,7 @@ bool rcuref_put_slowpath(rcuref_t *ref)
* require a retry. If this fails the caller is not
* allowed to deconstruct the object.
*/
- if (atomic_cmpxchg_release(&ref->refcnt, RCUREF_NOREF, RCUREF_DEAD) != RCUREF_NOREF)
+ if (!atomic_try_cmpxchg_release(&ref->refcnt, &cnt, RCUREF_DEAD))
return false;
/*