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. --- io_uring/tw.h | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 io_uring/tw.h (limited to 'io_uring/tw.h') diff --git a/io_uring/tw.h b/io_uring/tw.h new file mode 100644 index 000000000..3ade5ad57 --- /dev/null +++ b/io_uring/tw.h @@ -0,0 +1,117 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef IOU_TW_H +#define IOU_TW_H + +#include +#include +#include + +#include "mpscq.h" + +#define IO_LOCAL_TW_DEFAULT_MAX 20 + +/* + * Terminate the request if either of these conditions are true: + * + * 1) It's being executed by the original task, but that task is marked + * with PF_EXITING as it's exiting. + * 2) PF_KTHREAD is set, in which case the invoker of the task_work is + * our fallback task_work. + * 3) The ring has been closed and is going away. + */ +static inline bool io_should_terminate_tw(struct io_ring_ctx *ctx) +{ + return (current->flags & (PF_EXITING | PF_KTHREAD)) || percpu_ref_is_dying(&ctx->refs); +} + +void io_req_task_work_add_remote(struct io_kiocb *req, unsigned flags); +void tctx_task_work(struct callback_head *cb); +void io_tctx_fallback_work(struct work_struct *work); +int io_run_local_work(struct io_ring_ctx *ctx, int min_events, int max_events); +int io_run_task_work_sig(struct io_ring_ctx *ctx); + +__cold void io_cancel_local_task_work(struct io_ring_ctx *ctx); +int io_run_local_work_locked(struct io_ring_ctx *ctx, int min_events); + +void io_req_local_work_add(struct io_kiocb *req, unsigned flags); +void io_req_normal_work_add(struct io_kiocb *req); +void tctx_task_work_run(struct io_uring_task *tctx, unsigned int max_entries, unsigned int *count); + +static inline void __io_req_task_work_add(struct io_kiocb *req, unsigned flags) +{ + if (req->ctx->flags & IORING_SETUP_DEFER_TASKRUN) + io_req_local_work_add(req, flags); + else + io_req_normal_work_add(req); +} + +static inline void io_req_task_work_add(struct io_kiocb *req) +{ + __io_req_task_work_add(req, 0); +} + +static inline int io_run_task_work(void) +{ + bool ret = false; + + /* + * Always check-and-clear the task_work notification signal. With how + * signaling works for task_work, we can find it set with nothing to + * run. We need to clear it for that case, like get_signal() does. + */ + if (test_thread_flag(TIF_NOTIFY_SIGNAL)) + clear_notify_signal(); + /* + * PF_IO_WORKER never returns to userspace, so check here if we have + * notify work that needs processing. + */ + if (current->flags & PF_IO_WORKER) { + if (test_thread_flag(TIF_NOTIFY_RESUME)) { + __set_current_state(TASK_RUNNING); + resume_user_mode_work(NULL); + } + if (current->io_uring) { + unsigned int count = 0; + + __set_current_state(TASK_RUNNING); + tctx_task_work_run(current->io_uring, UINT_MAX, &count); + if (count) + ret = true; + } + } + if (task_work_pending(current)) { + __set_current_state(TASK_RUNNING); + task_work_run(); + ret = true; + } + + return ret; +} + +static inline bool io_local_work_pending(struct io_ring_ctx *ctx) +{ + return !mpscq_empty(&ctx->work_list); +} + +static inline bool io_task_work_pending(struct io_ring_ctx *ctx) +{ + return task_work_pending(current) || io_local_work_pending(ctx); +} + +static inline void io_tw_lock(struct io_ring_ctx *ctx, io_tw_token_t tw) +{ + lockdep_assert_held(&ctx->uring_lock); +} + +static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx) +{ + return likely(ctx->submitter_task == current); +} + +static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx) +{ + return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) || + ctx->submitter_task == current); +} + +#endif -- cgit v1.3.1