1 files changed, 148 insertions, 0 deletions
diff --git a/tools/testing/selftests/ublk/null.c b/tools/testing/selftests/ublk/null.c
new file mode 100644
index 000000000000..afe0b99d77ee
--- /dev/null
+++ b/tools/testing/selftests/ublk/null.c
@@ -0,0 +1,148 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include "kublk.h"
+
+#ifndef IORING_NOP_INJECT_RESULT
+#define IORING_NOP_INJECT_RESULT        (1U << 0)
+#endif
+
+#ifndef IORING_NOP_FIXED_BUFFER
+#define IORING_NOP_FIXED_BUFFER         (1U << 3)
+#endif
+
+static int ublk_null_tgt_init(const struct dev_ctx *ctx, struct ublk_dev *dev)
+{
+	const struct ublksrv_ctrl_dev_info *info = &dev->dev_info;
+	unsigned long dev_size = 250UL << 30;
+
+	dev->tgt.dev_size = dev_size;
+	dev->tgt.params = (struct ublk_params) {
+		.types = UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DMA_ALIGN |
+			UBLK_PARAM_TYPE_SEGMENT,
+		.basic = {
+			.logical_bs_shift	= 9,
+			.physical_bs_shift	= 12,
+			.io_opt_shift		= 12,
+			.io_min_shift		= 9,
+			.max_sectors		= info->max_io_buf_bytes >> 9,
+			.dev_sectors		= dev_size >> 9,
+		},
+		.dma = {
+			.alignment 		= 4095,
+		},
+		.seg = {
+			.seg_boundary_mask 	= 4095,
+			.max_segment_size 	= 32 << 10,
+			.max_segments 		= 32,
+		},
+	};
+
+	if (info->flags & UBLK_F_SUPPORT_ZERO_COPY)
+		dev->tgt.sq_depth = dev->tgt.cq_depth = 2 * info->queue_depth;
+	return 0;
+}
+
+static void __setup_nop_io(int tag, const struct ublksrv_io_desc *iod,
+		struct io_uring_sqe *sqe, int q_id)
+{
+	unsigned ublk_op = ublksrv_get_op(iod);
+
+	io_uring_prep_nop(sqe);
+	sqe->buf_index = tag;
+	sqe->flags |= IOSQE_FIXED_FILE;
+	sqe->rw_flags = IORING_NOP_FIXED_BUFFER | IORING_NOP_INJECT_RESULT;
+	sqe->len = iod->nr_sectors << 9; 	/* injected result */
+	sqe->user_data = build_user_data(tag, ublk_op, 0, q_id, 1);
+}
+
+static int null_queue_zc_io(struct ublk_queue *q, int tag)
+{
+	const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
+	struct io_uring_sqe *sqe[3];
+
+	ublk_io_alloc_sqes(ublk_get_io(q, tag), sqe, 3);
+
+	io_uring_prep_buf_register(sqe[0], 0, tag, q->q_id, ublk_get_io(q, tag)->buf_index);
+	sqe[0]->user_data = build_user_data(tag,
+			ublk_cmd_op_nr(sqe[0]->cmd_op), 0, q->q_id, 1);
+	sqe[0]->flags |= IOSQE_CQE_SKIP_SUCCESS | IOSQE_IO_HARDLINK;
+
+	__setup_nop_io(tag, iod, sqe[1], q->q_id);
+	sqe[1]->flags |= IOSQE_IO_HARDLINK;
+
+	io_uring_prep_buf_unregister(sqe[2], 0, tag, q->q_id, ublk_get_io(q, tag)->buf_index);
+	sqe[2]->user_data = build_user_data(tag, ublk_cmd_op_nr(sqe[2]->cmd_op), 0, q->q_id, 1);
+
+	// buf register is marked as IOSQE_CQE_SKIP_SUCCESS
+	return 2;
+}
+
+static int null_queue_auto_zc_io(struct ublk_queue *q, int tag)
+{
+	const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
+	struct io_uring_sqe *sqe[1];
+
+	ublk_io_alloc_sqes(ublk_get_io(q, tag), sqe, 1);
+	__setup_nop_io(tag, iod, sqe[0], q->q_id);
+	return 1;
+}
+
+static void ublk_null_io_done(struct ublk_queue *q, int tag,
+		const struct io_uring_cqe *cqe)
+{
+	unsigned op = user_data_to_op(cqe->user_data);
+	struct ublk_io *io = ublk_get_io(q, tag);
+
+	if (cqe->res < 0 || op != ublk_cmd_op_nr(UBLK_U_IO_UNREGISTER_IO_BUF)) {
+		if (!io->result)
+			io->result = cqe->res;
+		if (cqe->res < 0)
+			ublk_err("%s: io failed op %x user_data %lx\n",
+					__func__, op, cqe->user_data);
+	}
+
+	/* buffer register op is IOSQE_CQE_SKIP_SUCCESS */
+	if (op == ublk_cmd_op_nr(UBLK_U_IO_REGISTER_IO_BUF))
+		io->tgt_ios += 1;
+
+	if (ublk_completed_tgt_io(q, tag))
+		ublk_complete_io(q, tag, io->result);
+}
+
+static int ublk_null_queue_io(struct ublk_queue *q, int tag)
+{
+	const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
+	unsigned auto_zc = ublk_queue_use_auto_zc(q);
+	unsigned zc = ublk_queue_use_zc(q);
+	int queued;
+
+	if (auto_zc && !ublk_io_auto_zc_fallback(iod))
+		queued = null_queue_auto_zc_io(q, tag);
+	else if (zc)
+		queued = null_queue_zc_io(q, tag);
+	else {
+		ublk_complete_io(q, tag, iod->nr_sectors << 9);
+		return 0;
+	}
+	ublk_queued_tgt_io(q, tag, queued);
+	return 0;
+}
+
+/*
+ * return invalid buffer index for triggering auto buffer register failure,
+ * then UBLK_IO_RES_NEED_REG_BUF handling is covered
+ */
+static unsigned short ublk_null_buf_index(const struct ublk_queue *q, int tag)
+{
+	if (q->state & UBLKSRV_AUTO_BUF_REG_FALLBACK)
+		return (unsigned short)-1;
+	return q->ios[tag].buf_index;
+}
+
+const struct ublk_tgt_ops null_tgt_ops = {
+	.name = "null",
+	.init_tgt = ublk_null_tgt_init,
+	.queue_io = ublk_null_queue_io,
+	.tgt_io_done = ublk_null_io_done,
+	.buf_index = ublk_null_buf_index,
+};