Function __io_uring_queue_init_params

src/setup.c:327–402

}

int __io_uring_queue_init_params(unsigned entries, struct io_uring *ring,
				 struct io_uring_params *p, void *buf,
				 size_t buf_size)
{
	int fd, ret = 0;
	unsigned *sq_array;
	unsigned sq_entries, index;

	memset(ring, 0, sizeof(*ring));

	/*
	 * The kernel does this check already, but checking it here allows us
	 * to avoid handling it below.
	 */
	if (p->flags & IORING_SETUP_REGISTERED_FD_ONLY
	    && !(p->flags & IORING_SETUP_NO_MMAP))
		return -EINVAL;

	if (p->flags & IORING_SETUP_NO_MMAP) {
		ret = io_uring_alloc_huge(entries, p, &ring->sq, &ring->cq,
						buf, buf_size);
		if (ret < 0)
			return ret;
		if (buf)
			ring->int_flags |= INT_FLAG_APP_MEM;
	}

	fd = __sys_io_uring_setup(entries, p);
	if (fd < 0) {
		if ((p->flags & IORING_SETUP_NO_MMAP) &&
		    !(ring->int_flags & INT_FLAG_APP_MEM)) {
			__sys_munmap(ring->sq.sqes, ring->sq.sqes_sz);
			io_uring_unmap_rings(&ring->sq, &ring->cq);
		}
		return fd;
	}

	if (!(p->flags & IORING_SETUP_NO_MMAP)) {
		ret = io_uring_queue_mmap(fd, p, ring);
		if (ret) {
			__sys_close(fd);
			return ret;
		}
	} else {
		io_uring_setup_ring_pointers(p, &ring->sq, &ring->cq);
	}

	/*
	 * Directly map SQ slots to SQEs
	 */
	sq_entries = ring->sq.ring_entries;

	if (!(p->flags & IORING_SETUP_NO_SQARRAY)) {
		sq_array = ring->sq.array;
		for (index = 0; index < sq_entries; index++)
			sq_array[index] = index;
	}
	ring->features = p->features;