| 1 |
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| 2 | #include "io_uring.h"
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| 3 | #include "wait.h"
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| 4 | #include "loop.h"
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| 5 | #include "tctx.h"
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| 6 |
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| 7 | static inline int io_loop_nr_cqes(const struct io_ring_ctx *ctx,
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| 8 | const struct iou_loop_params *lp)
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| 9 | {
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| 10 | return lp->cq_wait_idx - READ_ONCE(ctx->rings->cq.tail);
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| 11 | }
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| 12 |
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| 13 | static inline void io_loop_wait_start(struct io_ring_ctx *ctx, unsigned nr_wait)
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| 14 | {
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| 15 | atomic_set(&ctx->cq_wait_nr, nr_wait);
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| 16 | set_current_state(TASK_INTERRUPTIBLE);
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| 17 | }
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| 18 |
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| 19 | static inline void io_loop_wait_finish(struct io_ring_ctx *ctx)
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| 20 | {
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| 21 | __set_current_state(TASK_RUNNING);
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| 22 | atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);
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| 23 | }
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| 24 |
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| 25 | static void io_loop_wait(struct io_ring_ctx *ctx, struct iou_loop_params *lp,
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| 26 | unsigned nr_wait)
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| 27 | {
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| 28 | io_loop_wait_start(ctx, nr_wait);
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| 29 |
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| 30 | if (unlikely(io_local_work_pending(ctx) ||
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| 31 | io_loop_nr_cqes(ctx, lp) <= 0) ||
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| 32 | READ_ONCE(ctx->check_cq)) {
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| 33 | io_loop_wait_finish(ctx);
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| 34 | return;
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| 35 | }
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| 36 |
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| 37 | mutex_unlock(&ctx->uring_lock);
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| 38 | schedule();
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| 39 | io_loop_wait_finish(ctx);
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| 40 | mutex_lock(&ctx->uring_lock);
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| 41 | }
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| 42 |
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| 43 | static int __io_run_loop(struct io_ring_ctx *ctx)
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| 44 | {
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| 45 | struct iou_loop_params lp = {};
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| 46 |
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| 47 | while (true) {
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| 48 | int nr_wait, step_res;
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| 49 |
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| 50 | if (unlikely(!ctx->loop_step))
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| 51 | return -EFAULT;
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| 52 |
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| 53 | step_res = ctx->loop_step(io_loop_mangle_ctx(ctx), &lp);
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| 54 | if (step_res == IOU_LOOP_STOP)
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| 55 | break;
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| 56 | if (step_res != IOU_LOOP_CONTINUE)
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| 57 | return -EINVAL;
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| 58 |
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| 59 | nr_wait = io_loop_nr_cqes(ctx, &lp);
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| 60 | if (nr_wait > 0)
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| 61 | io_loop_wait(ctx, &lp, nr_wait);
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| 62 | else
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| 63 | nr_wait = 0;
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| 64 |
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| 65 | if (task_work_pending(current)) {
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| 66 | mutex_unlock(&ctx->uring_lock);
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| 67 | io_run_task_work();
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| 68 | mutex_lock(&ctx->uring_lock);
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| 69 | }
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| 70 | if (unlikely(task_sigpending(current)))
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| 71 | return -EINTR;
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| 72 | io_run_local_work_locked(ctx, nr_wait);
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| 73 |
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| 74 | if (READ_ONCE(ctx->check_cq) & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
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| 75 | io_cqring_overflow_flush_locked(ctx);
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| 76 | }
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| 77 |
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| 78 | return 0;
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| 79 | }
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| 80 |
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| 81 | int io_run_loop(struct io_ring_ctx *ctx)
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| 82 | {
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| 83 | int ret;
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| 84 |
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| 85 | ret = io_uring_add_tctx_node(ctx);
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| 86 | if (unlikely(ret))
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| 87 | return ret;
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| 88 |
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| 89 | if (!io_allowed_run_tw(ctx))
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| 90 | return -EEXIST;
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| 91 |
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| 92 | mutex_lock(&ctx->uring_lock);
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| 93 | ret = __io_run_loop(ctx);
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| 94 | mutex_unlock(&ctx->uring_lock);
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| 95 | return ret;
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| 96 | }
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