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 void __setup_nop_io(int tag, const struct ublksrv_io_desc *iod, 46 struct io_uring_sqe *sqe, int q_id) 47 { 48 unsigned ublk_op = ublksrv_get_op(iod); 49 50 io_uring_prep_nop(sqe); 51 sqe->buf_index = tag; 52 sqe->flags |= IOSQE_FIXED_FILE; 53 sqe->rw_flags = IORING_NOP_FIXED_BUFFER | IORING_NOP_INJECT_RESULT; 54 sqe->len = iod->nr_sectors << 9; /* injected result */ 55 sqe->user_data = build_user_data(tag, ublk_op, 0, q_id, 1); 56 } 57 58 static int null_queue_zc_io(struct ublk_thread *t, struct ublk_queue *q, 59 int tag) 60 { 61 const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag); 62 struct io_uring_sqe *sqe[3]; 63 64 ublk_io_alloc_sqes(t, sqe, 3); 65 66 io_uring_prep_buf_register(sqe[0], 0, tag, q->q_id, ublk_get_io(q, tag)->buf_index); 67 sqe[0]->user_data = build_user_data(tag, 68 ublk_cmd_op_nr(sqe[0]->cmd_op), 0, q->q_id, 1); 69 sqe[0]->flags |= IOSQE_CQE_SKIP_SUCCESS | IOSQE_IO_HARDLINK; 70 71 __setup_nop_io(tag, iod, sqe[1], q->q_id); 72 sqe[1]->flags |= IOSQE_IO_HARDLINK; 73 74 io_uring_prep_buf_unregister(sqe[2], 0, tag, q->q_id, ublk_get_io(q, tag)->buf_index); 75 sqe[2]->user_data = build_user_data(tag, ublk_cmd_op_nr(sqe[2]->cmd_op), 0, q->q_id, 1); 76 77 // buf register is marked as IOSQE_CQE_SKIP_SUCCESS 78 return 2; 79 } 80 81 static int null_queue_auto_zc_io(struct ublk_thread *t, struct ublk_queue *q, 82 int tag) 83 { 84 const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag); 85 struct io_uring_sqe *sqe[1]; 86 87 ublk_io_alloc_sqes(t, sqe, 1); 88 __setup_nop_io(tag, iod, sqe[0], q->q_id); 89 return 1; 90 } 91 92 static void ublk_null_io_done(struct ublk_thread *t, struct ublk_queue *q, 93 const struct io_uring_cqe *cqe) 94 { 95 unsigned tag = user_data_to_tag(cqe->user_data); 96 unsigned op = user_data_to_op(cqe->user_data); 97 struct ublk_io *io = ublk_get_io(q, tag); 98 99 if (cqe->res < 0 || op != ublk_cmd_op_nr(UBLK_U_IO_UNREGISTER_IO_BUF)) { 100 if (!io->result) 101 io->result = cqe->res; 102 if (cqe->res < 0) 103 ublk_err("%s: io failed op %x user_data %lx\n", 104 __func__, op, cqe->user_data); 105 } 106 107 /* buffer register op is IOSQE_CQE_SKIP_SUCCESS */ 108 if (op == ublk_cmd_op_nr(UBLK_U_IO_REGISTER_IO_BUF)) 109 io->tgt_ios += 1; 110 111 if (ublk_completed_tgt_io(t, q, tag)) 112 ublk_complete_io(t, q, tag, io->result); 113 } 114 115 static int ublk_null_queue_io(struct ublk_thread *t, struct ublk_queue *q, 116 int tag) 117 { 118 const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag); 119 unsigned auto_zc = ublk_queue_use_auto_zc(q); 120 unsigned zc = ublk_queue_use_zc(q); 121 int queued; 122 123 if (auto_zc && !ublk_io_auto_zc_fallback(iod)) 124 queued = null_queue_auto_zc_io(t, q, tag); 125 else if (zc) 126 queued = null_queue_zc_io(t, q, tag); 127 else { 128 ublk_complete_io(t, q, tag, iod->nr_sectors << 9); 129 return 0; 130 } 131 ublk_queued_tgt_io(t, q, tag, queued); 132 return 0; 133 } 134 135 /* 136 * return invalid buffer index for triggering auto buffer register failure, 137 * then UBLK_IO_RES_NEED_REG_BUF handling is covered 138 */ 139 static unsigned short ublk_null_buf_index(const struct ublk_queue *q, int tag) 140 { 141 if (ublk_queue_auto_zc_fallback(q)) 142 return (unsigned short)-1; 143 return q->ios[tag].buf_index; 144 } 145 146 const struct ublk_tgt_ops null_tgt_ops = { 147 .name = "null", 148 .init_tgt = ublk_null_tgt_init, 149 .queue_io = ublk_null_queue_io, 150 .tgt_io_done = ublk_null_io_done, 151 .buf_index = ublk_null_buf_index, 152 }; 153