diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig index fdb81f2794cd..e19fcab016ba 100644 --- a/drivers/block/Kconfig +++ b/drivers/block/Kconfig @@ -408,6 +408,15 @@ config BLK_DEV_RBD If unsure, say N. +config BLK_DEV_UBLK + tristate "Userspace block driver (Experimental)" + select IO_URING + help + io_uring based userspace block driver. Together with ublk server, ublk + has been working well, but interface with userspace or command data + definition isn't finalized yet, and might change according to future + requirement, so mark is as experimental now. + source "drivers/block/rnbd/Kconfig" endif # BLK_DEV diff --git a/drivers/block/Makefile b/drivers/block/Makefile index 934a9c7c3a7c..be631352567e 100644 --- a/drivers/block/Makefile +++ b/drivers/block/Makefile @@ -39,4 +39,6 @@ obj-$(CONFIG_BLK_DEV_RNBD) += rnbd/ obj-$(CONFIG_BLK_DEV_NULL_BLK) += null_blk/ +obj-$(CONFIG_BLK_DEV_UBLK) += ublk_drv.o + swim_mod-y := swim.o swim_asm.o diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c new file mode 100644 index 000000000000..922a84c86fc6 --- /dev/null +++ b/drivers/block/ublk_drv.c @@ -0,0 +1,1530 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Userspace block device - block device which IO is handled from userspace + * + * Take full use of io_uring passthrough command for communicating with + * ublk userspace daemon(ublksrvd) for handling basic IO request. + * + * Copyright 2022 Ming Lei + * + * (part of code stolen from loop.c) + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define UBLK_MINORS (1U << MINORBITS) + +struct ublk_uring_cmd_pdu { + struct request *req; +}; + +/* + * io command is active: sqe cmd is received, and its cqe isn't done + * + * If the flag is set, the io command is owned by ublk driver, and waited + * for incoming blk-mq request from the ublk block device. + * + * If the flag is cleared, the io command will be completed, and owned by + * ublk server. + */ +#define UBLK_IO_FLAG_ACTIVE 0x01 + +/* + * IO command is completed via cqe, and it is being handled by ublksrv, and + * not committed yet + * + * Basically exclusively with UBLK_IO_FLAG_ACTIVE, so can be served for + * cross verification + */ +#define UBLK_IO_FLAG_OWNED_BY_SRV 0x02 + +/* + * IO command is aborted, so this flag is set in case of + * !UBLK_IO_FLAG_ACTIVE. + * + * After this flag is observed, any pending or new incoming request + * associated with this io command will be failed immediately + */ +#define UBLK_IO_FLAG_ABORTED 0x04 + +struct ublk_io { + /* userspace buffer address from io cmd */ + __u64 addr; + unsigned int flags; + int res; + + struct io_uring_cmd *cmd; +}; + +struct ublk_queue { + int q_id; + int q_depth; + + struct task_struct *ubq_daemon; + char *io_cmd_buf; + + unsigned long io_addr; /* mapped vm address */ + unsigned int max_io_sz; + bool abort_work_pending; + unsigned short nr_io_ready; /* how many ios setup */ + struct ublk_device *dev; + struct ublk_io ios[0]; +}; + +#define UBLK_DAEMON_MONITOR_PERIOD (5 * HZ) + +struct ublk_device { + struct gendisk *ub_disk; + struct request_queue *ub_queue; + + char *__queues; + + unsigned short queue_size; + unsigned short bs_shift; + struct ublksrv_ctrl_dev_info dev_info; + + struct blk_mq_tag_set tag_set; + + struct cdev cdev; + struct device cdev_dev; + + atomic_t ch_open_cnt; + int ub_number; + + struct mutex mutex; + + struct mm_struct *mm; + + struct completion completion; + unsigned int nr_queues_ready; + atomic_t nr_aborted_queues; + + /* + * Our ubq->daemon may be killed without any notification, so + * monitor each queue's daemon periodically + */ + struct delayed_work monitor_work; + struct work_struct stop_work; +}; + +static dev_t ublk_chr_devt; +static struct class *ublk_chr_class; + +static DEFINE_IDR(ublk_index_idr); +static DEFINE_SPINLOCK(ublk_idr_lock); +static wait_queue_head_t ublk_idr_wq; /* wait until one idr is freed */ + +static DEFINE_MUTEX(ublk_ctl_mutex); + +static struct miscdevice ublk_misc; + +static struct ublk_device *ublk_get_device(struct ublk_device *ub) +{ + if (kobject_get_unless_zero(&ub->cdev_dev.kobj)) + return ub; + return NULL; +} + +static void ublk_put_device(struct ublk_device *ub) +{ + put_device(&ub->cdev_dev); +} + +static inline struct ublk_queue *ublk_get_queue(struct ublk_device *dev, + int qid) +{ + return (struct ublk_queue *)&(dev->__queues[qid * dev->queue_size]); +} + +static inline bool ublk_rq_has_data(const struct request *rq) +{ + return rq->bio && bio_has_data(rq->bio); +} + +static inline struct ublksrv_io_desc *ublk_get_iod(struct ublk_queue *ubq, + int tag) +{ + return (struct ublksrv_io_desc *) + &(ubq->io_cmd_buf[tag * sizeof(struct ublksrv_io_desc)]); +} + +static inline char *ublk_queue_cmd_buf(struct ublk_device *ub, int q_id) +{ + return ublk_get_queue(ub, q_id)->io_cmd_buf; +} + +static inline int ublk_queue_cmd_buf_size(struct ublk_device *ub, int q_id) +{ + struct ublk_queue *ubq = ublk_get_queue(ub, q_id); + + return round_up(ubq->q_depth * sizeof(struct ublksrv_io_desc), + PAGE_SIZE); +} + +static int ublk_open(struct block_device *bdev, fmode_t mode) +{ + return 0; +} + +static void ublk_release(struct gendisk *disk, fmode_t mode) +{ +} + +static const struct block_device_operations ub_fops = { + .owner = THIS_MODULE, + .open = ublk_open, + .release = ublk_release, +}; + +#define UBLK_MAX_PIN_PAGES 32 + +struct ublk_map_data { + const struct ublk_queue *ubq; + const struct request *rq; + const struct ublk_io *io; + unsigned max_bytes; +}; + +struct ublk_io_iter { + struct page *pages[UBLK_MAX_PIN_PAGES]; + unsigned pg_off; /* offset in the 1st page in pages */ + int nr_pages; /* how many page pointers in pages */ + struct bio *bio; + struct bvec_iter iter; +}; + +static inline unsigned ublk_copy_io_pages(struct ublk_io_iter *data, + unsigned max_bytes, bool to_vm) +{ + const unsigned total = min_t(unsigned, max_bytes, + PAGE_SIZE - data->pg_off + + ((data->nr_pages - 1) << PAGE_SHIFT)); + unsigned done = 0; + unsigned pg_idx = 0; + + while (done < total) { + struct bio_vec bv = bio_iter_iovec(data->bio, data->iter); + const unsigned int bytes = min3(bv.bv_len, total - done, + (unsigned)(PAGE_SIZE - data->pg_off)); + void *bv_buf = bvec_kmap_local(&bv); + void *pg_buf = kmap_local_page(data->pages[pg_idx]); + + if (to_vm) + memcpy(pg_buf + data->pg_off, bv_buf, bytes); + else + memcpy(bv_buf, pg_buf + data->pg_off, bytes); + + kunmap_local(pg_buf); + kunmap_local(bv_buf); + + /* advance page array */ + data->pg_off += bytes; + if (data->pg_off == PAGE_SIZE) { + pg_idx += 1; + data->pg_off = 0; + } + + done += bytes; + + /* advance bio */ + bio_advance_iter_single(data->bio, &data->iter, bytes); + if (!data->iter.bi_size) { + data->bio = data->bio->bi_next; + if (data->bio == NULL) + break; + data->iter = data->bio->bi_iter; + } + } + + return done; +} + +static inline int ublk_copy_user_pages(struct ublk_map_data *data, + bool to_vm) +{ + const unsigned int gup_flags = to_vm ? FOLL_WRITE : 0; + const unsigned long start_vm = data->io->addr; + unsigned int done = 0; + struct ublk_io_iter iter = { + .pg_off = start_vm & (PAGE_SIZE - 1), + .bio = data->rq->bio, + .iter = data->rq->bio->bi_iter, + }; + const unsigned int nr_pages = round_up(data->max_bytes + + (start_vm & (PAGE_SIZE - 1)), PAGE_SIZE) >> PAGE_SHIFT; + + while (done < nr_pages) { + const unsigned to_pin = min_t(unsigned, UBLK_MAX_PIN_PAGES, + nr_pages - done); + unsigned i, len; + + iter.nr_pages = get_user_pages_fast(start_vm + + (done << PAGE_SHIFT), to_pin, gup_flags, + iter.pages); + if (iter.nr_pages <= 0) + return done == 0 ? iter.nr_pages : done; + len = ublk_copy_io_pages(&iter, data->max_bytes, to_vm); + for (i = 0; i < iter.nr_pages; i++) { + if (to_vm) + set_page_dirty(iter.pages[i]); + put_page(iter.pages[i]); + } + data->max_bytes -= len; + done += iter.nr_pages; + } + + return done; +} + +static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req, + struct ublk_io *io) +{ + const unsigned int rq_bytes = blk_rq_bytes(req); + /* + * no zero copy, we delay copy WRITE request data into ublksrv + * context and the big benefit is that pinning pages in current + * context is pretty fast, see ublk_pin_user_pages + */ + if (req_op(req) != REQ_OP_WRITE && req_op(req) != REQ_OP_FLUSH) + return rq_bytes; + + if (ublk_rq_has_data(req)) { + struct ublk_map_data data = { + .ubq = ubq, + .rq = req, + .io = io, + .max_bytes = rq_bytes, + }; + + ublk_copy_user_pages(&data, true); + + return rq_bytes - data.max_bytes; + } + return rq_bytes; +} + +static int ublk_unmap_io(const struct ublk_queue *ubq, + const struct request *req, + struct ublk_io *io) +{ + const unsigned int rq_bytes = blk_rq_bytes(req); + + if (req_op(req) == REQ_OP_READ && ublk_rq_has_data(req)) { + struct ublk_map_data data = { + .ubq = ubq, + .rq = req, + .io = io, + .max_bytes = io->res, + }; + + WARN_ON_ONCE(io->res > rq_bytes); + + ublk_copy_user_pages(&data, false); + + return io->res - data.max_bytes; + } + return rq_bytes; +} + +static inline unsigned int ublk_req_build_flags(struct request *req) +{ + unsigned flags = 0; + + if (req->cmd_flags & REQ_FAILFAST_DEV) + flags |= UBLK_IO_F_FAILFAST_DEV; + + if (req->cmd_flags & REQ_FAILFAST_TRANSPORT) + flags |= UBLK_IO_F_FAILFAST_TRANSPORT; + + if (req->cmd_flags & REQ_FAILFAST_DRIVER) + flags |= UBLK_IO_F_FAILFAST_DRIVER; + + if (req->cmd_flags & REQ_META) + flags |= UBLK_IO_F_META; + + if (req->cmd_flags & REQ_INTEGRITY) + flags |= UBLK_IO_F_INTEGRITY; + + if (req->cmd_flags & REQ_FUA) + flags |= UBLK_IO_F_FUA; + + if (req->cmd_flags & REQ_PREFLUSH) + flags |= UBLK_IO_F_PREFLUSH; + + if (req->cmd_flags & REQ_NOUNMAP) + flags |= UBLK_IO_F_NOUNMAP; + + if (req->cmd_flags & REQ_SWAP) + flags |= UBLK_IO_F_SWAP; + + return flags; +} + +static int ublk_setup_iod(struct ublk_queue *ubq, struct request *req) +{ + struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag); + struct ublk_io *io = &ubq->ios[req->tag]; + u32 ublk_op; + + switch (req_op(req)) { + case REQ_OP_READ: + ublk_op = UBLK_IO_OP_READ; + break; + case REQ_OP_WRITE: + ublk_op = UBLK_IO_OP_WRITE; + break; + case REQ_OP_FLUSH: + ublk_op = UBLK_IO_OP_FLUSH; + break; + case REQ_OP_DISCARD: + ublk_op = UBLK_IO_OP_DISCARD; + break; + case REQ_OP_WRITE_ZEROES: + ublk_op = UBLK_IO_OP_WRITE_ZEROES; + break; + default: + return BLK_STS_IOERR; + } + + /* need to translate since kernel may change */ + iod->op_flags = ublk_op | ublk_req_build_flags(req); + iod->nr_sectors = blk_rq_sectors(req); + iod->start_sector = blk_rq_pos(req); + iod->addr = io->addr; + + return BLK_STS_OK; +} + +static inline struct ublk_uring_cmd_pdu *ublk_get_uring_cmd_pdu( + struct io_uring_cmd *ioucmd) +{ + return (struct ublk_uring_cmd_pdu *)&ioucmd->pdu; +} + +static bool ubq_daemon_is_dying(struct ublk_queue *ubq) +{ + return ubq->ubq_daemon->flags & PF_EXITING; +} + +/* todo: handle partial completion */ +static void ublk_complete_rq(struct request *req) +{ + struct ublk_queue *ubq = req->mq_hctx->driver_data; + struct ublk_io *io = &ubq->ios[req->tag]; + unsigned int unmapped_bytes; + + /* failed read IO if nothing is read */ + if (!io->res && req_op(req) == REQ_OP_READ) + io->res = -EIO; + + if (io->res < 0) { + blk_mq_end_request(req, errno_to_blk_status(io->res)); + return; + } + + /* + * FLUSH or DISCARD usually won't return bytes returned, so end them + * directly. + * + * Both the two needn't unmap. + */ + if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE) { + blk_mq_end_request(req, BLK_STS_OK); + return; + } + + /* for READ request, writing data in iod->addr to rq buffers */ + unmapped_bytes = ublk_unmap_io(ubq, req, io); + + /* + * Extremely impossible since we got data filled in just before + * + * Re-read simply for this unlikely case. + */ + if (unlikely(unmapped_bytes < io->res)) + io->res = unmapped_bytes; + + if (blk_update_request(req, BLK_STS_OK, io->res)) + blk_mq_requeue_request(req, true); + else + __blk_mq_end_request(req, BLK_STS_OK); +} + +/* + * __ublk_fail_req() may be called from abort context or ->ubq_daemon + * context during exiting, so lock is required. + * + * Also aborting may not be started yet, keep in mind that one failed + * request may be issued by block layer again. + */ +static void __ublk_fail_req(struct ublk_io *io, struct request *req) +{ + WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_ACTIVE); + + if (!(io->flags & UBLK_IO_FLAG_ABORTED)) { + io->flags |= UBLK_IO_FLAG_ABORTED; + blk_mq_end_request(req, BLK_STS_IOERR); + } +} + +#define UBLK_REQUEUE_DELAY_MS 3 + +static void ublk_rq_task_work_cb(struct io_uring_cmd *cmd) +{ + struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd); + struct ublk_device *ub = cmd->file->private_data; + struct request *req = pdu->req; + struct ublk_queue *ubq = req->mq_hctx->driver_data; + int tag = req->tag; + struct ublk_io *io = &ubq->ios[tag]; + bool task_exiting = current != ubq->ubq_daemon || + (current->flags & PF_EXITING); + unsigned int mapped_bytes; + + pr_devel("%s: complete: op %d, qid %d tag %d io_flags %x addr %llx\n", + __func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags, + ublk_get_iod(ubq, req->tag)->addr); + + if (unlikely(task_exiting)) { + blk_mq_end_request(req, BLK_STS_IOERR); + mod_delayed_work(system_wq, &ub->monitor_work, 0); + return; + } + + mapped_bytes = ublk_map_io(ubq, req, io); + + /* partially mapped, update io descriptor */ + if (unlikely(mapped_bytes != blk_rq_bytes(req))) { + /* + * Nothing mapped, retry until we succeed. + * + * We may never succeed in mapping any bytes here because + * of OOM. TODO: reserve one buffer with single page pinned + * for providing forward progress guarantee. + */ + if (unlikely(!mapped_bytes)) { + blk_mq_requeue_request(req, false); + blk_mq_delay_kick_requeue_list(req->q, + UBLK_REQUEUE_DELAY_MS); + return; + } + + ublk_get_iod(ubq, req->tag)->nr_sectors = + mapped_bytes >> 9; + } + + /* mark this cmd owned by ublksrv */ + io->flags |= UBLK_IO_FLAG_OWNED_BY_SRV; + + /* + * clear ACTIVE since we are done with this sqe/cmd slot + * We can only accept io cmd in case of being not active. + */ + io->flags &= ~UBLK_IO_FLAG_ACTIVE; + + /* tell ublksrv one io request is coming */ + io_uring_cmd_done(io->cmd, UBLK_IO_RES_OK, 0); +} + +static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct ublk_queue *ubq = hctx->driver_data; + struct request *rq = bd->rq; + struct io_uring_cmd *cmd = ubq->ios[rq->tag].cmd; + struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd); + blk_status_t res; + + /* fill iod to slot in io cmd buffer */ + res = ublk_setup_iod(ubq, rq); + if (unlikely(res != BLK_STS_OK)) + return BLK_STS_IOERR; + + blk_mq_start_request(bd->rq); + + if (unlikely(ubq_daemon_is_dying(ubq))) { + mod_delayed_work(system_wq, &ubq->dev->monitor_work, 0); + return BLK_STS_IOERR; + } + + pdu->req = rq; + io_uring_cmd_complete_in_task(cmd, ublk_rq_task_work_cb); + + return BLK_STS_OK; +} + + +static int ublk_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data, + unsigned int hctx_idx) +{ + struct ublk_device *ub = hctx->queue->queuedata; + struct ublk_queue *ubq = ublk_get_queue(ub, hctx->queue_num); + + hctx->driver_data = ubq; + return 0; +} + +static const struct blk_mq_ops ublk_mq_ops = { + .queue_rq = ublk_queue_rq, + .init_hctx = ublk_init_hctx, +}; + +static int ublk_ch_open(struct inode *inode, struct file *filp) +{ + struct ublk_device *ub = container_of(inode->i_cdev, + struct ublk_device, cdev); + + if (atomic_cmpxchg(&ub->ch_open_cnt, 0, 1) == 0) { + filp->private_data = ub; + return 0; + } + return -EBUSY; +} + +static int ublk_ch_release(struct inode *inode, struct file *filp) +{ + struct ublk_device *ub = filp->private_data; + + while (atomic_cmpxchg(&ub->ch_open_cnt, 1, 0) != 1) + cpu_relax(); + + filp->private_data = NULL; + return 0; +} + +/* map pre-allocated per-queue cmd buffer to ublksrv daemon */ +static int ublk_ch_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct ublk_device *ub = filp->private_data; + size_t sz = vma->vm_end - vma->vm_start; + unsigned max_sz = UBLK_MAX_QUEUE_DEPTH * sizeof(struct ublksrv_io_desc); + unsigned long pfn, end, phys_off = vma->vm_pgoff << PAGE_SHIFT; + int q_id, ret = 0; + + mutex_lock(&ub->mutex); + if (!ub->mm) + ub->mm = current->mm; + if (current->mm != ub->mm) + ret = -EINVAL; + mutex_unlock(&ub->mutex); + + if (ret) + return ret; + + if (vma->vm_flags & VM_WRITE) + return -EPERM; + + end = UBLKSRV_CMD_BUF_OFFSET + ub->dev_info.nr_hw_queues * max_sz; + if (phys_off < UBLKSRV_CMD_BUF_OFFSET || phys_off >= end) + return -EINVAL; + + q_id = (phys_off - UBLKSRV_CMD_BUF_OFFSET) / max_sz; + pr_devel("%s: qid %d, pid %d, addr %lx pg_off %lx sz %lu\n", + __func__, q_id, current->pid, vma->vm_start, + phys_off, (unsigned long)sz); + + if (sz != ublk_queue_cmd_buf_size(ub, q_id)) + return -EINVAL; + + pfn = virt_to_phys(ublk_queue_cmd_buf(ub, q_id)) >> PAGE_SHIFT; + return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); +} + +static void ublk_commit_completion(struct ublk_device *ub, + struct ublksrv_io_cmd *ub_cmd) +{ + u32 qid = ub_cmd->q_id, tag = ub_cmd->tag; + struct ublk_queue *ubq = ublk_get_queue(ub, qid); + struct ublk_io *io = &ubq->ios[tag]; + struct request *req; + + /* now this cmd slot is owned by nbd driver */ + io->flags &= ~UBLK_IO_FLAG_OWNED_BY_SRV; + io->res = ub_cmd->result; + + /* find the io request and complete */ + req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag); + + if (req && likely(!blk_should_fake_timeout(req->q))) + ublk_complete_rq(req); +} + +/* + * When ->ubq_daemon is exiting, either new request is ended immediately, + * or any queued io command is drained, so it is safe to abort queue + * lockless + */ +static void ublk_abort_queue(struct ublk_device *ub, struct ublk_queue *ubq) +{ + int i; + + if (!ublk_get_device(ub)) + return; + + for (i = 0; i < ubq->q_depth; i++) { + struct ublk_io *io = &ubq->ios[i]; + + if (!(io->flags & UBLK_IO_FLAG_ACTIVE)) { + struct request *rq; + + /* + * Either we fail the request or ublk_rq_task_work_fn + * will do it + */ + rq = blk_mq_tag_to_rq(ub->tag_set.tags[ubq->q_id], i); + if (rq) + __ublk_fail_req(io, rq); + } + } + ublk_put_device(ub); +} + +static void ublk_daemon_monitor_work(struct work_struct *work) +{ + struct ublk_device *ub = + container_of(work, struct ublk_device, monitor_work.work); + int i; + + for (i = 0; i < ub->dev_info.nr_hw_queues; i++) { + struct ublk_queue *ubq = ublk_get_queue(ub, i); + + if (ubq_daemon_is_dying(ubq)) { + schedule_work(&ub->stop_work); + + /* abort queue is for making forward progress */ + ublk_abort_queue(ub, ubq); + } + } + + /* + * We can't schedule monitor work after ublk_remove() is started. + * + * No need ub->mutex, monitor work are canceled after state is marked + * as DEAD, so DEAD state is observed reliably. + */ + if (ub->dev_info.state != UBLK_S_DEV_DEAD) + schedule_delayed_work(&ub->monitor_work, + UBLK_DAEMON_MONITOR_PERIOD); +} + +static void ublk_cancel_queue(struct ublk_queue *ubq) +{ + int i; + + for (i = 0; i < ubq->q_depth; i++) { + struct ublk_io *io = &ubq->ios[i]; + + if (io->flags & UBLK_IO_FLAG_ACTIVE) + io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0); + } +} + +/* Cancel all pending commands, must be called after del_gendisk() returns */ +static void ublk_cancel_dev(struct ublk_device *ub) +{ + int i; + + for (i = 0; i < ub->dev_info.nr_hw_queues; i++) + ublk_cancel_queue(ublk_get_queue(ub, i)); +} + +static void ublk_stop_dev(struct ublk_device *ub) +{ + mutex_lock(&ub->mutex); + if (!disk_live(ub->ub_disk)) + goto unlock; + + del_gendisk(ub->ub_disk); + ub->dev_info.state = UBLK_S_DEV_DEAD; + ub->dev_info.ublksrv_pid = -1; + ublk_cancel_dev(ub); + unlock: + mutex_unlock(&ub->mutex); + cancel_delayed_work_sync(&ub->monitor_work); +} + +static int ublk_ctrl_stop_dev(struct ublk_device *ub) +{ + ublk_stop_dev(ub); + cancel_work_sync(&ub->stop_work); + return 0; +} + +static inline bool ublk_queue_ready(struct ublk_queue *ubq) +{ + return ubq->nr_io_ready == ubq->q_depth; +} + +/* device can only be started after all IOs are ready */ +static void ublk_mark_io_ready(struct ublk_device *ub, struct ublk_queue *ubq) +{ + mutex_lock(&ub->mutex); + ubq->nr_io_ready++; + if (ublk_queue_ready(ubq)) { + ubq->ubq_daemon = current; + get_task_struct(ubq->ubq_daemon); + ub->nr_queues_ready++; + } + if (ub->nr_queues_ready == ub->dev_info.nr_hw_queues) + complete_all(&ub->completion); + mutex_unlock(&ub->mutex); +} + +static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) +{ + struct ublksrv_io_cmd *ub_cmd = (struct ublksrv_io_cmd *)cmd->cmd; + struct ublk_device *ub = cmd->file->private_data; + struct ublk_queue *ubq; + struct ublk_io *io; + u32 cmd_op = cmd->cmd_op; + unsigned tag = ub_cmd->tag; + int ret = -EINVAL; + + pr_devel("%s: received: cmd op %d queue %d tag %d result %d\n", + __func__, cmd->cmd_op, ub_cmd->q_id, tag, + ub_cmd->result); + + if (!(issue_flags & IO_URING_F_SQE128)) + goto out; + + if (ub_cmd->q_id >= ub->dev_info.nr_hw_queues) + goto out; + + ubq = ublk_get_queue(ub, ub_cmd->q_id); + if (!ubq || ub_cmd->q_id != ubq->q_id) + goto out; + + if (ubq->ubq_daemon && ubq->ubq_daemon != current) + goto out; + + if (tag >= ubq->q_depth) + goto out; + + io = &ubq->ios[tag]; + + /* there is pending io cmd, something must be wrong */ + if (io->flags & UBLK_IO_FLAG_ACTIVE) { + ret = -EBUSY; + goto out; + } + + switch (cmd_op) { + case UBLK_IO_FETCH_REQ: + /* UBLK_IO_FETCH_REQ is only allowed before queue is setup */ + if (ublk_queue_ready(ubq)) { + ret = -EBUSY; + goto out; + } + /* + * The io is being handled by server, so COMMIT_RQ is expected + * instead of FETCH_REQ + */ + if (io->flags & UBLK_IO_FLAG_OWNED_BY_SRV) + goto out; + /* FETCH_RQ has to provide IO buffer */ + if (!ub_cmd->addr) + goto out; + io->cmd = cmd; + io->flags |= UBLK_IO_FLAG_ACTIVE; + io->addr = ub_cmd->addr; + + ublk_mark_io_ready(ub, ubq); + break; + case UBLK_IO_COMMIT_AND_FETCH_REQ: + /* FETCH_RQ has to provide IO buffer */ + if (!ub_cmd->addr) + goto out; + if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV)) + goto out; + io->addr = ub_cmd->addr; + io->flags |= UBLK_IO_FLAG_ACTIVE; + io->cmd = cmd; + ublk_commit_completion(ub, ub_cmd); + break; + default: + goto out; + } + return -EIOCBQUEUED; + + out: + io->flags &= ~UBLK_IO_FLAG_ACTIVE; + io_uring_cmd_done(cmd, ret, 0); + pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n", + __func__, cmd_op, tag, ret, io->flags); + return -EIOCBQUEUED; +} + +static const struct file_operations ublk_ch_fops = { + .owner = THIS_MODULE, + .open = ublk_ch_open, + .release = ublk_ch_release, + .llseek = no_llseek, + .uring_cmd = ublk_ch_uring_cmd, + .mmap = ublk_ch_mmap, +}; + +static void ublk_deinit_queue(struct ublk_device *ub, int q_id) +{ + int size = ublk_queue_cmd_buf_size(ub, q_id); + struct ublk_queue *ubq = ublk_get_queue(ub, q_id); + + if (ubq->ubq_daemon) + put_task_struct(ubq->ubq_daemon); + if (ubq->io_cmd_buf) + free_pages((unsigned long)ubq->io_cmd_buf, get_order(size)); +} + +static int ublk_init_queue(struct ublk_device *ub, int q_id) +{ + struct ublk_queue *ubq = ublk_get_queue(ub, q_id); + gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO; + void *ptr; + int size; + + ubq->q_id = q_id; + ubq->q_depth = ub->dev_info.queue_depth; + size = ublk_queue_cmd_buf_size(ub, q_id); + + ptr = (void *) __get_free_pages(gfp_flags, get_order(size)); + if (!ptr) + return -ENOMEM; + + ubq->io_cmd_buf = ptr; + ubq->dev = ub; + return 0; +} + +static void ublk_deinit_queues(struct ublk_device *ub) +{ + int nr_queues = ub->dev_info.nr_hw_queues; + int i; + + if (!ub->__queues) + return; + + for (i = 0; i < nr_queues; i++) + ublk_deinit_queue(ub, i); + kfree(ub->__queues); +} + +static int ublk_init_queues(struct ublk_device *ub) +{ + int nr_queues = ub->dev_info.nr_hw_queues; + int depth = ub->dev_info.queue_depth; + int ubq_size = sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io); + int i, ret = -ENOMEM; + + ub->queue_size = ubq_size; + ub->__queues = kcalloc(nr_queues, ubq_size, GFP_KERNEL); + if (!ub->__queues) + return ret; + + for (i = 0; i < nr_queues; i++) { + if (ublk_init_queue(ub, i)) + goto fail; + } + + init_completion(&ub->completion); + return 0; + + fail: + ublk_deinit_queues(ub); + return ret; +} + +static int __ublk_alloc_dev_number(struct ublk_device *ub, int idx) +{ + int i = idx; + int err; + + spin_lock(&ublk_idr_lock); + /* allocate id, if @id >= 0, we're requesting that specific id */ + if (i >= 0) { + err = idr_alloc(&ublk_index_idr, ub, i, i + 1, GFP_NOWAIT); + if (err == -ENOSPC) + err = -EEXIST; + } else { + err = idr_alloc(&ublk_index_idr, ub, 0, 0, GFP_NOWAIT); + } + spin_unlock(&ublk_idr_lock); + + if (err >= 0) + ub->ub_number = err; + + return err; +} + +static struct ublk_device *__ublk_create_dev(int idx) +{ + struct ublk_device *ub = NULL; + int ret; + + ub = kzalloc(sizeof(*ub), GFP_KERNEL); + if (!ub) + return ERR_PTR(-ENOMEM); + + ret = __ublk_alloc_dev_number(ub, idx); + if (ret < 0) { + kfree(ub); + return ERR_PTR(ret); + } + return ub; +} + +static void __ublk_destroy_dev(struct ublk_device *ub) +{ + spin_lock(&ublk_idr_lock); + idr_remove(&ublk_index_idr, ub->ub_number); + wake_up_all(&ublk_idr_wq); + spin_unlock(&ublk_idr_lock); + + mutex_destroy(&ub->mutex); + + kfree(ub); +} + +static void ublk_cdev_rel(struct device *dev) +{ + struct ublk_device *ub = container_of(dev, struct ublk_device, cdev_dev); + + put_disk(ub->ub_disk); + + blk_mq_free_tag_set(&ub->tag_set); + + ublk_deinit_queues(ub); + + __ublk_destroy_dev(ub); +} + +static int ublk_add_chdev(struct ublk_device *ub) +{ + struct device *dev = &ub->cdev_dev; + int minor = ub->ub_number; + int ret; + + dev->parent = ublk_misc.this_device; + dev->devt = MKDEV(MAJOR(ublk_chr_devt), minor); + dev->class = ublk_chr_class; + dev->release = ublk_cdev_rel; + device_initialize(dev); + + ret = dev_set_name(dev, "ublkc%d", minor); + if (ret) + goto fail; + + cdev_init(&ub->cdev, &ublk_ch_fops); + ret = cdev_device_add(&ub->cdev, dev); + if (ret) + goto fail; + return 0; + fail: + put_device(dev); + return ret; +} + +static void ublk_stop_work_fn(struct work_struct *work) +{ + struct ublk_device *ub = + container_of(work, struct ublk_device, stop_work); + + ublk_stop_dev(ub); +} + +static void ublk_update_capacity(struct ublk_device *ub) +{ + unsigned int max_rq_bytes; + + /* make max request buffer size aligned with PAGE_SIZE */ + max_rq_bytes = round_down(ub->dev_info.rq_max_blocks << + ub->bs_shift, PAGE_SIZE); + ub->dev_info.rq_max_blocks = max_rq_bytes >> ub->bs_shift; + + set_capacity(ub->ub_disk, ub->dev_info.dev_blocks << (ub->bs_shift - 9)); +} + +/* add disk & cdev, cleanup everything in case of failure */ +static int ublk_add_dev(struct ublk_device *ub) +{ + struct gendisk *disk; + int err = -ENOMEM; + int bsize; + + /* We are not ready to support zero copy */ + ub->dev_info.flags[0] &= ~UBLK_F_SUPPORT_ZERO_COPY; + + bsize = ub->dev_info.block_size; + ub->bs_shift = ilog2(bsize); + + ub->dev_info.nr_hw_queues = min_t(unsigned int, + ub->dev_info.nr_hw_queues, nr_cpu_ids); + + INIT_WORK(&ub->stop_work, ublk_stop_work_fn); + INIT_DELAYED_WORK(&ub->monitor_work, ublk_daemon_monitor_work); + + if (ublk_init_queues(ub)) + goto out_destroy_dev; + + ub->tag_set.ops = &ublk_mq_ops; + ub->tag_set.nr_hw_queues = ub->dev_info.nr_hw_queues; + ub->tag_set.queue_depth = ub->dev_info.queue_depth; + ub->tag_set.numa_node = NUMA_NO_NODE; + ub->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; + ub->tag_set.driver_data = ub; + + err = blk_mq_alloc_tag_set(&ub->tag_set); + if (err) + goto out_deinit_queues; + + disk = ub->ub_disk = blk_mq_alloc_disk(&ub->tag_set, ub); + if (IS_ERR(disk)) { + err = PTR_ERR(disk); + goto out_cleanup_tags; + } + ub->ub_queue = ub->ub_disk->queue; + + ub->ub_queue->queuedata = ub; + + blk_queue_logical_block_size(ub->ub_queue, bsize); + blk_queue_physical_block_size(ub->ub_queue, bsize); + blk_queue_io_min(ub->ub_queue, bsize); + + blk_queue_max_hw_sectors(ub->ub_queue, ub->dev_info.rq_max_blocks << + (ub->bs_shift - 9)); + + ub->ub_queue->limits.discard_granularity = PAGE_SIZE; + + blk_queue_max_discard_sectors(ub->ub_queue, UINT_MAX >> 9); + blk_queue_max_write_zeroes_sectors(ub->ub_queue, UINT_MAX >> 9); + + ublk_update_capacity(ub); + + disk->fops = &ub_fops; + disk->private_data = ub; + disk->queue = ub->ub_queue; + sprintf(disk->disk_name, "ublkb%d", ub->ub_number); + + mutex_init(&ub->mutex); + + /* add char dev so that ublksrv daemon can be setup */ + err = ublk_add_chdev(ub); + if (err) + return err; + + /* don't expose disk now until we got start command from cdev */ + + return 0; + +out_cleanup_tags: + blk_mq_free_tag_set(&ub->tag_set); +out_deinit_queues: + ublk_deinit_queues(ub); +out_destroy_dev: + __ublk_destroy_dev(ub); + return err; +} + +static void ublk_remove(struct ublk_device *ub) +{ + ublk_ctrl_stop_dev(ub); + + cdev_device_del(&ub->cdev, &ub->cdev_dev); + put_device(&ub->cdev_dev); +} + +static struct ublk_device *ublk_get_device_from_id(int idx) +{ + struct ublk_device *ub = NULL; + + if (idx < 0) + return NULL; + + spin_lock(&ublk_idr_lock); + ub = idr_find(&ublk_index_idr, idx); + if (ub) + ub = ublk_get_device(ub); + spin_unlock(&ublk_idr_lock); + + return ub; +} + +static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd) +{ + struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; + int ret = -EINVAL; + int ublksrv_pid = (int)header->data[0]; + unsigned long dev_blocks = header->data[1]; + + if (ublksrv_pid <= 0) + return ret; + + wait_for_completion_interruptible(&ub->completion); + + schedule_delayed_work(&ub->monitor_work, UBLK_DAEMON_MONITOR_PERIOD); + + mutex_lock(&ub->mutex); + if (!disk_live(ub->ub_disk)) { + /* We may get disk size updated */ + if (dev_blocks) { + ub->dev_info.dev_blocks = dev_blocks; + ublk_update_capacity(ub); + } + ub->dev_info.ublksrv_pid = ublksrv_pid; + ret = add_disk(ub->ub_disk); + if (!ret) + ub->dev_info.state = UBLK_S_DEV_LIVE; + } else { + ret = -EEXIST; + } + mutex_unlock(&ub->mutex); + + return ret; +} + +static struct blk_mq_hw_ctx *ublk_get_hw_queue(struct ublk_device *ub, + unsigned int index) +{ + struct blk_mq_hw_ctx *hctx; + unsigned long i; + + queue_for_each_hw_ctx(ub->ub_queue, hctx, i) + if (hctx->queue_num == index) + return hctx; + return NULL; +} + +static int ublk_ctrl_get_queue_affinity(struct io_uring_cmd *cmd) +{ + struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; + void __user *argp = (void __user *)(unsigned long)header->addr; + struct blk_mq_hw_ctx *hctx; + struct ublk_device *ub; + unsigned long queue; + unsigned int retlen; + int ret; + + ub = ublk_get_device_from_id(header->dev_id); + if (!ub) + goto out; + + ret = -EINVAL; + queue = header->data[0]; + if (queue >= ub->dev_info.nr_hw_queues) + goto out; + hctx = ublk_get_hw_queue(ub, queue); + if (!hctx) + goto out; + + retlen = min_t(unsigned short, header->len, cpumask_size()); + if (copy_to_user(argp, hctx->cpumask, retlen)) { + ret = -EFAULT; + goto out; + } + if (retlen != header->len) { + if (clear_user(argp + retlen, header->len - retlen)) { + ret = -EFAULT; + goto out; + } + } + ret = 0; + out: + if (ub) + ublk_put_device(ub); + return ret; +} + +static int ublk_ctrl_add_dev(const struct ublksrv_ctrl_dev_info *info, + void __user *argp, int idx) +{ + struct ublk_device *ub; + int ret; + + ret = mutex_lock_killable(&ublk_ctl_mutex); + if (ret) + return ret; + + ub = __ublk_create_dev(idx); + if (!IS_ERR_OR_NULL(ub)) { + memcpy(&ub->dev_info, info, sizeof(*info)); + + /* update device id */ + ub->dev_info.dev_id = ub->ub_number; + + ret = ublk_add_dev(ub); + if (!ret) { + if (copy_to_user(argp, &ub->dev_info, sizeof(*info))) { + ublk_remove(ub); + ret = -EFAULT; + } + } + } else { + if (IS_ERR(ub)) + ret = PTR_ERR(ub); + else + ret = -ENOMEM; + } + mutex_unlock(&ublk_ctl_mutex); + + return ret; +} + +static inline bool ublk_idr_freed(int id) +{ + void *ptr; + + spin_lock(&ublk_idr_lock); + ptr = idr_find(&ublk_index_idr, id); + spin_unlock(&ublk_idr_lock); + + return ptr == NULL; +} + +static int ublk_ctrl_del_dev(int idx) +{ + struct ublk_device *ub; + int ret; + + ret = mutex_lock_killable(&ublk_ctl_mutex); + if (ret) + return ret; + + ub = ublk_get_device_from_id(idx); + if (ub) { + ublk_remove(ub); + ublk_put_device(ub); + ret = 0; + } else { + ret = -ENODEV; + } + + /* + * Wait until the idr is removed, then it can be reused after + * DEL_DEV command is returned. + */ + if (!ret) + wait_event(ublk_idr_wq, ublk_idr_freed(idx)); + mutex_unlock(&ublk_ctl_mutex); + + return ret; +} + + +static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info *info) +{ + pr_devel("%s: dev id %d flags %llx\n", __func__, + info->dev_id, info->flags[0]); + pr_devel("\t nr_hw_queues %d queue_depth %d block size %d dev_capacity %lld\n", + info->nr_hw_queues, info->queue_depth, + info->block_size, info->dev_blocks); +} + +static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd *cmd) +{ + struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; + + pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n", + __func__, cmd->cmd_op, header->dev_id, header->queue_id, + header->data[0], header->addr, header->len); +} + +static int ublk_ctrl_cmd_validate(struct io_uring_cmd *cmd, + struct ublksrv_ctrl_dev_info *info) +{ + struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; + u32 cmd_op = cmd->cmd_op; + void __user *argp = (void __user *)(unsigned long)header->addr; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + switch (cmd_op) { + case UBLK_CMD_GET_DEV_INFO: + if (header->len < sizeof(*info) || !header->addr) + return -EINVAL; + break; + case UBLK_CMD_ADD_DEV: + if (header->len < sizeof(*info) || !header->addr) + return -EINVAL; + if (copy_from_user(info, argp, sizeof(*info)) != 0) + return -EFAULT; + ublk_dump_dev_info(info); + if (header->dev_id != info->dev_id) { + printk(KERN_WARNING "%s: cmd %x, dev id not match %u %u\n", + __func__, cmd_op, header->dev_id, + info->dev_id); + return -EINVAL; + } + if (header->queue_id != (u16)-1) { + printk(KERN_WARNING "%s: cmd %x queue_id is wrong %x\n", + __func__, cmd_op, header->queue_id); + return -EINVAL; + } + break; + case UBLK_CMD_GET_QUEUE_AFFINITY: + if ((header->len * BITS_PER_BYTE) < nr_cpu_ids) + return -EINVAL; + if (header->len & (sizeof(unsigned long)-1)) + return -EINVAL; + if (!header->addr) + return -EINVAL; + }; + + return 0; +} + +static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, + unsigned int issue_flags) +{ + struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; + void __user *argp = (void __user *)(unsigned long)header->addr; + struct ublksrv_ctrl_dev_info info; + u32 cmd_op = cmd->cmd_op; + struct ublk_device *ub; + int ret = -EINVAL; + + ublk_ctrl_cmd_dump(cmd); + + if (!(issue_flags & IO_URING_F_SQE128)) + goto out; + + ret = ublk_ctrl_cmd_validate(cmd, &info); + if (ret) + goto out; + + ret = -ENODEV; + switch (cmd_op) { + case UBLK_CMD_START_DEV: + ub = ublk_get_device_from_id(header->dev_id); + if (ub) { + ret = ublk_ctrl_start_dev(ub, cmd); + ublk_put_device(ub); + } + break; + case UBLK_CMD_STOP_DEV: + ub = ublk_get_device_from_id(header->dev_id); + if (ub) { + ret = ublk_ctrl_stop_dev(ub); + ublk_put_device(ub); + } + break; + case UBLK_CMD_GET_DEV_INFO: + ub = ublk_get_device_from_id(header->dev_id); + if (ub) { + if (copy_to_user(argp, &ub->dev_info, sizeof(info))) + ret = -EFAULT; + else + ret = 0; + ublk_put_device(ub); + } + break; + case UBLK_CMD_ADD_DEV: + ret = ublk_ctrl_add_dev(&info, argp, header->dev_id); + break; + case UBLK_CMD_DEL_DEV: + ret = ublk_ctrl_del_dev(header->dev_id); + break; + case UBLK_CMD_GET_QUEUE_AFFINITY: + ret = ublk_ctrl_get_queue_affinity(cmd); + break; + default: + break; + }; + out: + io_uring_cmd_done(cmd, ret, 0); + pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n", + __func__, ret, cmd->cmd_op, header->dev_id, header->queue_id); + return -EIOCBQUEUED; +} + +static const struct file_operations ublk_ctl_fops = { + .open = nonseekable_open, + .uring_cmd = ublk_ctrl_uring_cmd, + .owner = THIS_MODULE, + .llseek = noop_llseek, +}; + +static struct miscdevice ublk_misc = { + .minor = MISC_DYNAMIC_MINOR, + .name = "ublk-control", + .fops = &ublk_ctl_fops, +}; + +static int __init ublk_init(void) +{ + int ret; + + init_waitqueue_head(&ublk_idr_wq); + + ret = misc_register(&ublk_misc); + if (ret) + return ret; + + ret = alloc_chrdev_region(&ublk_chr_devt, 0, UBLK_MINORS, "ublk-char"); + if (ret) + goto unregister_mis; + + ublk_chr_class = class_create(THIS_MODULE, "ublk-char"); + if (IS_ERR(ublk_chr_class)) { + ret = PTR_ERR(ublk_chr_class); + goto free_chrdev_region; + } + return 0; + +free_chrdev_region: + unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS); +unregister_mis: + misc_deregister(&ublk_misc); + return ret; +} + +static void __exit ublk_exit(void) +{ + struct ublk_device *ub; + int id; + + class_destroy(ublk_chr_class); + + misc_deregister(&ublk_misc); + + idr_for_each_entry(&ublk_index_idr, ub, id) + ublk_remove(ub); + + idr_destroy(&ublk_index_idr); + unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS); +} + +module_init(ublk_init); +module_exit(ublk_exit); + +MODULE_AUTHOR("Ming Lei "); +MODULE_LICENSE("GPL"); diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h new file mode 100644 index 000000000000..4f0c16ec875e --- /dev/null +++ b/include/uapi/linux/ublk_cmd.h @@ -0,0 +1,156 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef USER_BLK_DRV_CMD_INC_H +#define USER_BLK_DRV_CMD_INC_H + +#include + +/* ublk server command definition */ + +/* + * Admin commands, issued by ublk server, and handled by ublk driver. + */ +#define UBLK_CMD_GET_QUEUE_AFFINITY 0x01 +#define UBLK_CMD_GET_DEV_INFO 0x02 +#define UBLK_CMD_ADD_DEV 0x04 +#define UBLK_CMD_DEL_DEV 0x05 +#define UBLK_CMD_START_DEV 0x06 +#define UBLK_CMD_STOP_DEV 0x07 + +/* + * IO commands, issued by ublk server, and handled by ublk driver. + * + * FETCH_REQ: issued via sqe(URING_CMD) beforehand for fetching IO request + * from ublk driver, should be issued only when starting device. After + * the associated cqe is returned, request's tag can be retrieved via + * cqe->userdata. + * + * COMMIT_AND_FETCH_REQ: issued via sqe(URING_CMD) after ublkserver handled + * this IO request, request's handling result is committed to ublk + * driver, meantime FETCH_REQ is piggyback, and FETCH_REQ has to be + * handled before completing io request. + */ +#define UBLK_IO_FETCH_REQ 0x20 +#define UBLK_IO_COMMIT_AND_FETCH_REQ 0x21 + +/* only ABORT means that no re-fetch */ +#define UBLK_IO_RES_OK 0 +#define UBLK_IO_RES_ABORT (-ENODEV) + +#define UBLKSRV_CMD_BUF_OFFSET 0 +#define UBLKSRV_IO_BUF_OFFSET 0x80000000 + +/* tag bit is 12bit, so at most 4096 IOs for each queue */ +#define UBLK_MAX_QUEUE_DEPTH 4096 + +/* + * zero copy requires 4k block size, and can remap ublk driver's io + * request into ublksrv's vm space + */ +#define UBLK_F_SUPPORT_ZERO_COPY (1UL << 0) + +/* device state */ +#define UBLK_S_DEV_DEAD 0 +#define UBLK_S_DEV_LIVE 1 + +/* shipped via sqe->cmd of io_uring command */ +struct ublksrv_ctrl_cmd { + /* sent to which device, must be valid */ + __u32 dev_id; + + /* sent to which queue, must be -1 if the cmd isn't for queue */ + __u16 queue_id; + /* + * cmd specific buffer, can be IN or OUT. + */ + __u16 len; + __u64 addr; + + /* inline data */ + __u64 data[2]; +}; + +struct ublksrv_ctrl_dev_info { + __u16 nr_hw_queues; + __u16 queue_depth; + __u16 block_size; + __u16 state; + + __u32 rq_max_blocks; + __u32 dev_id; + + __u64 dev_blocks; + + __s32 ublksrv_pid; + __s32 reserved0; + __u64 flags[2]; + + /* For ublksrv internal use, invisible to ublk driver */ + __u64 ublksrv_flags; + __u64 reserved1[9]; +}; + +#define UBLK_IO_OP_READ 0 +#define UBLK_IO_OP_WRITE 1 +#define UBLK_IO_OP_FLUSH 2 +#define UBLK_IO_OP_DISCARD 3 +#define UBLK_IO_OP_WRITE_SAME 4 +#define UBLK_IO_OP_WRITE_ZEROES 5 + +#define UBLK_IO_F_FAILFAST_DEV (1U << 8) +#define UBLK_IO_F_FAILFAST_TRANSPORT (1U << 9) +#define UBLK_IO_F_FAILFAST_DRIVER (1U << 10) +#define UBLK_IO_F_META (1U << 11) +#define UBLK_IO_F_INTEGRITY (1U << 12) +#define UBLK_IO_F_FUA (1U << 13) +#define UBLK_IO_F_PREFLUSH (1U << 14) +#define UBLK_IO_F_NOUNMAP (1U << 15) +#define UBLK_IO_F_SWAP (1U << 16) + +/* + * io cmd is described by this structure, and stored in share memory, indexed + * by request tag. + * + * The data is stored by ublk driver, and read by ublksrv after one fetch command + * returns. + */ +struct ublksrv_io_desc { + /* op: bit 0-7, flags: bit 8-31 */ + __u32 op_flags; + + __u32 nr_sectors; + + /* start sector for this io */ + __u64 start_sector; + + /* buffer address in ublksrv daemon vm space, from ublk driver */ + __u64 addr; +}; + +static inline __u8 ublksrv_get_op(const struct ublksrv_io_desc *iod) +{ + return iod->op_flags & 0xff; +} + +static inline __u32 ublksrv_get_flags(const struct ublksrv_io_desc *iod) +{ + return iod->op_flags >> 8; +} + +/* issued to ublk driver via /dev/ublkcN */ +struct ublksrv_io_cmd { + __u16 q_id; + + /* for fetch/commit which result */ + __u16 tag; + + /* io result, it is valid for COMMIT* command only */ + __s32 result; + + /* + * userspace buffer address in ublksrv daemon process, valid for + * FETCH* command only + */ + __u64 addr; +}; + +#endif