diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index fdb81f2794cde1dd8ed376e362258c887fae1b51..e19fcab016ba2fc4a2588a6d033c93c21ead2258 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 934a9c7c3a7c6be54a64558114d0b7b888ca0319..be631352567e7ba37d99bb8d3228b83d8fa5b7bf 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 0000000000000000000000000000000000000000..922a84c86fc68eecd9c00ab1e326f7368d741fec
--- /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 <ming.lei@redhat.com>
+ *
+ * (part of code stolen from loop.c)
+ */
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/file.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/major.h>
+#include <linux/wait.h>
+#include <linux/blkdev.h>
+#include <linux/init.h>
+#include <linux/swap.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/mutex.h>
+#include <linux/writeback.h>
+#include <linux/completion.h>
+#include <linux/highmem.h>
+#include <linux/sysfs.h>
+#include <linux/miscdevice.h>
+#include <linux/falloc.h>
+#include <linux/uio.h>
+#include <linux/ioprio.h>
+#include <linux/sched/mm.h>
+#include <linux/uaccess.h>
+#include <linux/cdev.h>
+#include <linux/io_uring.h>
+#include <linux/blk-mq.h>
+#include <linux/delay.h>
+#include <linux/mm.h>
+#include <asm/page.h>
+#include <uapi/linux/ublk_cmd.h>
+
+#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 <ming.lei@redhat.com>");
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
new file mode 100644
index 0000000000000000000000000000000000000000..4f0c16ec875e4f5239286844512c98ed02d70817
--- /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 <linux/types.h>
+
+/* 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