io_uring/loop.c

Source file repositories/reference/linux-study-clean/io_uring/loop.c

File Facts

System
Linux kernel
Corpus path
io_uring/loop.c
Extension
.c
Size
2016 bytes
Lines
92
Domain
Kernel Services
Bucket
io_uring
Inferred role
Kernel Services: implementation source
Status
source implementation candidate

Why This File Exists

Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.

Dependency Surface

Detected Declarations

Annotated Snippet

READ_ONCE(ctx->check_cq)) {
		io_loop_wait_finish(ctx);
		return;
	}

	mutex_unlock(&ctx->uring_lock);
	schedule();
	io_loop_wait_finish(ctx);
	mutex_lock(&ctx->uring_lock);
}

static int __io_run_loop(struct io_ring_ctx *ctx)
{
	struct iou_loop_params lp = {};

	while (true) {
		int nr_wait, step_res;

		if (unlikely(!ctx->loop_step))
			return -EFAULT;

		step_res = ctx->loop_step(io_loop_mangle_ctx(ctx), &lp);
		if (step_res == IOU_LOOP_STOP)
			break;
		if (step_res != IOU_LOOP_CONTINUE)
			return -EINVAL;

		nr_wait = io_loop_nr_cqes(ctx, &lp);
		if (nr_wait > 0)
			io_loop_wait(ctx, &lp, nr_wait);
		else
			nr_wait = 0;

		if (task_work_pending(current)) {
			mutex_unlock(&ctx->uring_lock);
			io_run_task_work();
			mutex_lock(&ctx->uring_lock);
		}
		if (unlikely(task_sigpending(current)))
			return -EINTR;
		io_run_local_work_locked(ctx, nr_wait);

		if (READ_ONCE(ctx->check_cq) & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
			io_cqring_overflow_flush_locked(ctx);
	}

	return 0;
}

int io_run_loop(struct io_ring_ctx *ctx)
{
	int ret;

	if (!io_allowed_run_tw(ctx))
		return -EEXIST;

	mutex_lock(&ctx->uring_lock);
	ret = __io_run_loop(ctx);
	mutex_unlock(&ctx->uring_lock);
	return ret;
}

Annotation

Implementation Notes