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// SPDX-License-Identifier: GPL-2.0
#include "kublk.h"
static enum io_uring_op ublk_to_uring_op(const struct ublksrv_io_desc *iod, int zc)
{
unsigned ublk_op = ublksrv_get_op(iod);
if (ublk_op == UBLK_IO_OP_READ)
return zc ? IORING_OP_READ_FIXED : IORING_OP_READ;
else if (ublk_op == UBLK_IO_OP_WRITE)
return zc ? IORING_OP_WRITE_FIXED : IORING_OP_WRITE;
assert(0);
}
static int loop_queue_flush_io(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
{
unsigned ublk_op = ublksrv_get_op(iod);
struct io_uring_sqe *sqe[1];
ublk_queue_alloc_sqes(q, sqe, 1);
io_uring_prep_fsync(sqe[0], 1 /*fds[1]*/, IORING_FSYNC_DATASYNC);
io_uring_sqe_set_flags(sqe[0], IOSQE_FIXED_FILE);
/* bit63 marks us as tgt io */
sqe[0]->user_data = build_user_data(tag, ublk_op, 0, 1);
return 1;
}
static int loop_queue_tgt_rw_io(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
{
unsigned ublk_op = ublksrv_get_op(iod);
int zc = ublk_queue_use_zc(q);
enum io_uring_op op = ublk_to_uring_op(iod, zc);
struct io_uring_sqe *sqe[3];
if (!zc) {
ublk_queue_alloc_sqes(q, sqe, 1);
if (!sqe[0])
return -ENOMEM;
io_uring_prep_rw(op, sqe[0], 1 /*fds[1]*/,
(void *)iod->addr,
iod->nr_sectors << 9,
iod->start_sector << 9);
io_uring_sqe_set_flags(sqe[0], IOSQE_FIXED_FILE);
/* bit63 marks us as tgt io */
sqe[0]->user_data = build_user_data(tag, ublk_op, 0, 1);
return 1;
}
ublk_queue_alloc_sqes(q, sqe, 3);
io_uring_prep_buf_register(sqe[0], 0, tag, q->q_id, tag);
sqe[0]->flags |= IOSQE_CQE_SKIP_SUCCESS | IOSQE_IO_HARDLINK;
sqe[0]->user_data = build_user_data(tag,
ublk_cmd_op_nr(sqe[0]->cmd_op), 0, 1);
io_uring_prep_rw(op, sqe[1], 1 /*fds[1]*/, 0,
iod->nr_sectors << 9,
iod->start_sector << 9);
sqe[1]->buf_index = tag;
sqe[1]->flags |= IOSQE_FIXED_FILE | IOSQE_IO_HARDLINK;
sqe[1]->user_data = build_user_data(tag, ublk_op, 0, 1);
io_uring_prep_buf_unregister(sqe[2], 0, tag, q->q_id, tag);
sqe[2]->user_data = build_user_data(tag, ublk_cmd_op_nr(sqe[2]->cmd_op), 0, 1);
return 2;
}
static int loop_queue_tgt_io(struct ublk_queue *q, int tag)
{
const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
unsigned ublk_op = ublksrv_get_op(iod);
int ret;
switch (ublk_op) {
case UBLK_IO_OP_FLUSH:
ret = loop_queue_flush_io(q, iod, tag);
break;
case UBLK_IO_OP_WRITE_ZEROES:
case UBLK_IO_OP_DISCARD:
ret = -ENOTSUP;
break;
case UBLK_IO_OP_READ:
case UBLK_IO_OP_WRITE:
ret = loop_queue_tgt_rw_io(q, iod, tag);
break;
default:
ret = -EINVAL;
break;
}
ublk_dbg(UBLK_DBG_IO, "%s: tag %d ublk io %x %llx %u\n", __func__, tag,
iod->op_flags, iod->start_sector, iod->nr_sectors << 9);
return ret;
}
static int ublk_loop_queue_io(struct ublk_queue *q, int tag)
{
int queued = loop_queue_tgt_io(q, tag);
ublk_queued_tgt_io(q, tag, queued);
return 0;
}
static void ublk_loop_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_loop_tgt_init(const struct dev_ctx *ctx, struct ublk_dev *dev)
{
unsigned long long bytes;
int ret;
struct ublk_params p = {
.types = UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DMA_ALIGN,
.basic = {
.attrs = UBLK_ATTR_VOLATILE_CACHE,
.logical_bs_shift = 9,
.physical_bs_shift = 12,
.io_opt_shift = 12,
.io_min_shift = 9,
.max_sectors = dev->dev_info.max_io_buf_bytes >> 9,
},
.dma = {
.alignment = 511,
},
};
ret = backing_file_tgt_init(dev);
if (ret)
return ret;
if (dev->tgt.nr_backing_files != 1)
return -EINVAL;
bytes = dev->tgt.backing_file_size[0];
dev->tgt.dev_size = bytes;
p.basic.dev_sectors = bytes >> 9;
dev->tgt.params = p;
return 0;
}
const struct ublk_tgt_ops loop_tgt_ops = {
.name = "loop",
.init_tgt = ublk_loop_tgt_init,
.deinit_tgt = backing_file_tgt_deinit,
.queue_io = ublk_loop_queue_io,
.tgt_io_done = ublk_loop_io_done,
};
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