1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #include "io_uring.h" 3 #include "wait.h" 4 #include "loop.h" 5 #include "tctx.h" 6 7 static inline int io_loop_nr_cqes(const struct io_ring_ctx *ctx, 8 const struct iou_loop_params *lp) 9 { 10 return lp->cq_wait_idx - READ_ONCE(ctx->rings->cq.tail); 11 } 12 13 static inline void io_loop_wait_finish(struct io_ring_ctx *ctx) 14 { 15 __set_current_state(TASK_RUNNING); 16 atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT); 17 } 18 19 static void io_loop_wait(struct io_ring_ctx *ctx, struct iou_loop_params *lp, 20 unsigned nr_wait) 21 { 22 io_cq_wait_arm(ctx, nr_wait); 23 24 if (unlikely(io_local_work_pending(ctx) || 25 io_loop_nr_cqes(ctx, lp) <= 0) || 26 READ_ONCE(ctx->check_cq)) { 27 io_loop_wait_finish(ctx); 28 return; 29 } 30 31 mutex_unlock(&ctx->uring_lock); 32 schedule(); 33 io_loop_wait_finish(ctx); 34 mutex_lock(&ctx->uring_lock); 35 } 36 37 static int __io_run_loop(struct io_ring_ctx *ctx) 38 { 39 struct iou_loop_params lp = {}; 40 41 while (true) { 42 int nr_wait, step_res; 43 44 if (unlikely(!ctx->loop_step)) 45 return -EFAULT; 46 47 step_res = ctx->loop_step(io_loop_mangle_ctx(ctx), &lp); 48 if (step_res == IOU_LOOP_STOP) 49 break; 50 if (step_res != IOU_LOOP_CONTINUE) 51 return -EINVAL; 52 53 nr_wait = io_loop_nr_cqes(ctx, &lp); 54 if (nr_wait > 0) 55 io_loop_wait(ctx, &lp, nr_wait); 56 else 57 nr_wait = 0; 58 59 if (task_work_pending(current)) { 60 mutex_unlock(&ctx->uring_lock); 61 io_run_task_work(); 62 mutex_lock(&ctx->uring_lock); 63 } 64 if (unlikely(task_sigpending(current))) 65 return -EINTR; 66 io_run_local_work_locked(ctx, nr_wait); 67 68 if (READ_ONCE(ctx->check_cq) & BIT(IO_CHECK_CQ_OVERFLOW_BIT)) 69 io_cqring_overflow_flush_locked(ctx); 70 } 71 72 return 0; 73 } 74 75 int io_run_loop(struct io_ring_ctx *ctx) 76 { 77 int ret; 78 79 ret = io_uring_add_tctx_node(ctx); 80 if (unlikely(ret)) 81 return ret; 82 83 if (!io_allowed_run_tw(ctx)) 84 return -EEXIST; 85 86 mutex_lock(&ctx->uring_lock); 87 ret = __io_run_loop(ctx); 88 mutex_unlock(&ctx->uring_lock); 89 return ret; 90 } 91