1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 #include "kublk.h" 4 5 #ifndef IORING_NOP_INJECT_RESULT 6 #define IORING_NOP_INJECT_RESULT (1U << 0) 7 #endif 8 9 #ifndef IORING_NOP_FIXED_BUFFER 10 #define IORING_NOP_FIXED_BUFFER (1U << 3) 11 #endif 12 13 static int ublk_null_tgt_init(const struct dev_ctx *ctx, struct ublk_dev *dev) 14 { 15 const struct ublksrv_ctrl_dev_info *info = &dev->dev_info; 16 unsigned long dev_size = 250UL << 30; 17 18 dev->tgt.dev_size = dev_size; 19 dev->tgt.params = (struct ublk_params) { 20 .types = UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DMA_ALIGN | 21 UBLK_PARAM_TYPE_SEGMENT, 22 .basic = { 23 .logical_bs_shift = 9, 24 .physical_bs_shift = 12, 25 .io_opt_shift = 12, 26 .io_min_shift = 9, 27 .max_sectors = info->max_io_buf_bytes >> 9, 28 .dev_sectors = dev_size >> 9, 29 }, 30 .dma = { 31 .alignment = 4095, 32 }, 33 .seg = { 34 .seg_boundary_mask = 4095, 35 .max_segment_size = 32 << 10, 36 .max_segments = 32, 37 }, 38 }; 39 40 if (info->flags & UBLK_F_SUPPORT_ZERO_COPY) 41 dev->tgt.sq_depth = dev->tgt.cq_depth = 2 * info->queue_depth; 42 return 0; 43 } 44 45 static int null_queue_zc_io(struct ublk_queue *q, int tag) 46 { 47 const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag); 48 unsigned ublk_op = ublksrv_get_op(iod); 49 struct io_uring_sqe *sqe[3]; 50 51 ublk_queue_alloc_sqes(q, sqe, 3); 52 53 io_uring_prep_buf_register(sqe[0], 0, tag, q->q_id, tag); 54 sqe[0]->user_data = build_user_data(tag, 55 ublk_cmd_op_nr(sqe[0]->cmd_op), 0, 1); 56 sqe[0]->flags |= IOSQE_CQE_SKIP_SUCCESS | IOSQE_IO_HARDLINK; 57 58 io_uring_prep_nop(sqe[1]); 59 sqe[1]->buf_index = tag; 60 sqe[1]->flags |= IOSQE_FIXED_FILE | IOSQE_IO_HARDLINK; 61 sqe[1]->rw_flags = IORING_NOP_FIXED_BUFFER | IORING_NOP_INJECT_RESULT; 62 sqe[1]->len = iod->nr_sectors << 9; /* injected result */ 63 sqe[1]->user_data = build_user_data(tag, ublk_op, 0, 1); 64 65 io_uring_prep_buf_unregister(sqe[2], 0, tag, q->q_id, tag); 66 sqe[2]->user_data = build_user_data(tag, ublk_cmd_op_nr(sqe[2]->cmd_op), 0, 1); 67 68 // buf register is marked as IOSQE_CQE_SKIP_SUCCESS 69 return 2; 70 } 71 72 static void ublk_null_io_done(struct ublk_queue *q, int tag, 73 const struct io_uring_cqe *cqe) 74 { 75 unsigned op = user_data_to_op(cqe->user_data); 76 struct ublk_io *io = ublk_get_io(q, tag); 77 78 if (cqe->res < 0 || op != ublk_cmd_op_nr(UBLK_U_IO_UNREGISTER_IO_BUF)) { 79 if (!io->result) 80 io->result = cqe->res; 81 if (cqe->res < 0) 82 ublk_err("%s: io failed op %x user_data %lx\n", 83 __func__, op, cqe->user_data); 84 } 85 86 /* buffer register op is IOSQE_CQE_SKIP_SUCCESS */ 87 if (op == ublk_cmd_op_nr(UBLK_U_IO_REGISTER_IO_BUF)) 88 io->tgt_ios += 1; 89 90 if (ublk_completed_tgt_io(q, tag)) 91 ublk_complete_io(q, tag, io->result); 92 } 93 94 static int ublk_null_queue_io(struct ublk_queue *q, int tag) 95 { 96 const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag); 97 int zc = ublk_queue_use_zc(q); 98 int queued; 99 100 if (!zc) { 101 ublk_complete_io(q, tag, iod->nr_sectors << 9); 102 return 0; 103 } 104 105 queued = null_queue_zc_io(q, tag); 106 ublk_queued_tgt_io(q, tag, queued); 107 return 0; 108 } 109 110 const struct ublk_tgt_ops null_tgt_ops = { 111 .name = "null", 112 .init_tgt = ublk_null_tgt_init, 113 .queue_io = ublk_null_queue_io, 114 .tgt_io_done = ublk_null_io_done, 115 }; 116