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