From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- include/asm-generic/local.h | 57 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 include/asm-generic/local.h (limited to 'include/asm-generic/local.h') diff --git a/include/asm-generic/local.h b/include/asm-generic/local.h new file mode 100644 index 000000000..7f97018df --- /dev/null +++ b/include/asm-generic/local.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_GENERIC_LOCAL_H +#define _ASM_GENERIC_LOCAL_H + +#include +#include +#include + +/* + * A signed long type for operations which are atomic for a single CPU. + * Usually used in combination with per-cpu variables. + * + * This is the default implementation, which uses atomic_long_t. Which is + * rather pointless. The whole point behind local_t is that some processors + * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs + * running on this CPU. local_t allows exploitation of such capabilities. + */ + +/* Implement in terms of atomics. */ + +/* Don't use typedef: don't want them to be mixed with atomic_t's. */ +typedef struct +{ + atomic_long_t a; +} local_t; + +#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) } + +#define local_read(l) atomic_long_read(&(l)->a) +#define local_set(l,i) atomic_long_set((&(l)->a),(i)) +#define local_inc(l) atomic_long_inc(&(l)->a) +#define local_dec(l) atomic_long_dec(&(l)->a) +#define local_add(i,l) atomic_long_add((i),(&(l)->a)) +#define local_sub(i,l) atomic_long_sub((i),(&(l)->a)) + +#define local_sub_and_test(i, l) atomic_long_sub_and_test((i), (&(l)->a)) +#define local_dec_and_test(l) atomic_long_dec_and_test(&(l)->a) +#define local_inc_and_test(l) atomic_long_inc_and_test(&(l)->a) +#define local_add_negative(i, l) atomic_long_add_negative((i), (&(l)->a)) +#define local_add_return(i, l) atomic_long_add_return((i), (&(l)->a)) +#define local_sub_return(i, l) atomic_long_sub_return((i), (&(l)->a)) +#define local_inc_return(l) atomic_long_inc_return(&(l)->a) + +#define local_cmpxchg(l, o, n) atomic_long_cmpxchg((&(l)->a), (o), (n)) +#define local_try_cmpxchg(l, po, n) atomic_long_try_cmpxchg((&(l)->a), (po), (n)) +#define local_xchg(l, n) atomic_long_xchg((&(l)->a), (n)) +#define local_add_unless(l, _a, u) atomic_long_add_unless((&(l)->a), (_a), (u)) +#define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a) + +/* Non-atomic variants, ie. preemption disabled and won't be touched + * in interrupt, etc. Some archs can optimize this case well. */ +#define __local_inc(l) local_set((l), local_read(l) + 1) +#define __local_dec(l) local_set((l), local_read(l) - 1) +#define __local_add(i,l) local_set((l), local_read(l) + (i)) +#define __local_sub(i,l) local_set((l), local_read(l) - (i)) + +#endif /* _ASM_GENERIC_LOCAL_H */ -- cgit v1.3.1