1 // SPDX-License-Identifier: GPL-2.0 2 #ifndef IOU_TW_H 3 #define IOU_TW_H 4 5 #include <linux/sched.h> 6 #include <linux/percpu-refcount.h> 7 #include <linux/io_uring_types.h> 8 9 #include "mpscq.h" 10 11 #define IO_LOCAL_TW_DEFAULT_MAX 20 12 13 /* 14 * Terminate the request if either of these conditions are true: 15 * 16 * 1) It's being executed by the original task, but that task is marked 17 * with PF_EXITING as it's exiting. 18 * 2) PF_KTHREAD is set, in which case the invoker of the task_work is 19 * our fallback task_work. 20 * 3) The ring has been closed and is going away. 21 */ 22 static inline bool io_should_terminate_tw(struct io_ring_ctx *ctx) 23 { 24 return (current->flags & (PF_EXITING | PF_KTHREAD)) || percpu_ref_is_dying(&ctx->refs); 25 } 26 27 void io_req_task_work_add_remote(struct io_kiocb *req, unsigned flags); 28 void tctx_task_work(struct callback_head *cb); 29 void io_tctx_fallback_work(struct work_struct *work); 30 int io_run_local_work(struct io_ring_ctx *ctx, int min_events, int max_events); 31 int io_run_task_work_sig(struct io_ring_ctx *ctx); 32 33 __cold void io_cancel_local_task_work(struct io_ring_ctx *ctx); 34 int io_run_local_work_locked(struct io_ring_ctx *ctx, int min_events); 35 36 void io_req_local_work_add(struct io_kiocb *req, unsigned flags); 37 void io_req_normal_work_add(struct io_kiocb *req); 38 void tctx_task_work_run(struct io_uring_task *tctx, unsigned int max_entries, unsigned int *count); 39 40 static inline void __io_req_task_work_add(struct io_kiocb *req, unsigned flags) 41 { 42 if (req->ctx->flags & IORING_SETUP_DEFER_TASKRUN) 43 io_req_local_work_add(req, flags); 44 else 45 io_req_normal_work_add(req); 46 } 47 48 static inline void io_req_task_work_add(struct io_kiocb *req) 49 { 50 __io_req_task_work_add(req, 0); 51 } 52 53 static inline int io_run_task_work(void) 54 { 55 bool ret = false; 56 57 /* 58 * Always check-and-clear the task_work notification signal. With how 59 * signaling works for task_work, we can find it set with nothing to 60 * run. We need to clear it for that case, like get_signal() does. 61 */ 62 if (test_thread_flag(TIF_NOTIFY_SIGNAL)) 63 clear_notify_signal(); 64 /* 65 * PF_IO_WORKER never returns to userspace, so check here if we have 66 * notify work that needs processing. 67 */ 68 if (current->flags & PF_IO_WORKER) { 69 if (test_thread_flag(TIF_NOTIFY_RESUME)) { 70 __set_current_state(TASK_RUNNING); 71 resume_user_mode_work(NULL); 72 } 73 if (current->io_uring) { 74 unsigned int count = 0; 75 76 __set_current_state(TASK_RUNNING); 77 tctx_task_work_run(current->io_uring, UINT_MAX, &count); 78 if (count) 79 ret = true; 80 } 81 } 82 if (task_work_pending(current)) { 83 __set_current_state(TASK_RUNNING); 84 task_work_run(); 85 ret = true; 86 } 87 88 return ret; 89 } 90 91 static inline bool io_local_work_pending(struct io_ring_ctx *ctx) 92 { 93 return !mpscq_empty(&ctx->work_list); 94 } 95 96 static inline bool io_task_work_pending(struct io_ring_ctx *ctx) 97 { 98 return task_work_pending(current) || io_local_work_pending(ctx); 99 } 100 101 static inline void io_tw_lock(struct io_ring_ctx *ctx, io_tw_token_t tw) 102 { 103 lockdep_assert_held(&ctx->uring_lock); 104 } 105 106 static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx) 107 { 108 return likely(ctx->submitter_task == current); 109 } 110 111 static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx) 112 { 113 return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) || 114 ctx->submitter_task == current); 115 } 116 117 #endif 118