1 files changed, 143 insertions, 73 deletions

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index c73cc57ec547..c7331f519750 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -53,7 +53,8 @@
 		| UBLK_F_NEED_GET_DATA \
 		| UBLK_F_USER_RECOVERY \
 		| UBLK_F_USER_RECOVERY_REISSUE \
-		| UBLK_F_UNPRIVILEGED_DEV)
+		| UBLK_F_UNPRIVILEGED_DEV \
+		| UBLK_F_CMD_IOCTL_ENCODE)
 
 /* All UBLK_PARAM_TYPE_* should be included here */
 #define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
@@ -128,6 +129,7 @@ struct ublk_queue {
 	unsigned long io_addr;	/* mapped vm address */
 	unsigned int max_io_sz;
 	bool force_abort;
+	bool timeout;
 	unsigned short nr_io_ready;	/* how many ios setup */
 	struct ublk_device *dev;
 	struct ublk_io ios[];
@@ -246,7 +248,7 @@ static int ublk_validate_params(const struct ublk_device *ub)
 	if (ub->params.types & UBLK_PARAM_TYPE_BASIC) {
 		const struct ublk_param_basic *p = &ub->params.basic;
 
-		if (p->logical_bs_shift > PAGE_SHIFT)
+		if (p->logical_bs_shift > PAGE_SHIFT || p->logical_bs_shift < 9)
 			return -EINVAL;
 
 		if (p->logical_bs_shift > p->physical_bs_shift)
@@ -298,9 +300,7 @@ static inline bool ublk_can_use_task_work(const struct ublk_queue *ubq)
 
 static inline bool ublk_need_get_data(const struct ublk_queue *ubq)
 {
-	if (ubq->flags & UBLK_F_NEED_GET_DATA)
-		return true;
-	return false;
+	return ubq->flags & UBLK_F_NEED_GET_DATA;
 }
 
 static struct ublk_device *ublk_get_device(struct ublk_device *ub)
@@ -349,25 +349,19 @@ static inline int ublk_queue_cmd_buf_size(struct ublk_device *ub, int q_id)
 static inline bool ublk_queue_can_use_recovery_reissue(
 		struct ublk_queue *ubq)
 {
-	if ((ubq->flags & UBLK_F_USER_RECOVERY) &&
-			(ubq->flags & UBLK_F_USER_RECOVERY_REISSUE))
-		return true;
-	return false;
+	return (ubq->flags & UBLK_F_USER_RECOVERY) &&
+			(ubq->flags & UBLK_F_USER_RECOVERY_REISSUE);
 }
 
 static inline bool ublk_queue_can_use_recovery(
 		struct ublk_queue *ubq)
 {
-	if (ubq->flags & UBLK_F_USER_RECOVERY)
-		return true;
-	return false;
+	return ubq->flags & UBLK_F_USER_RECOVERY;
 }
 
 static inline bool ublk_can_use_recovery(struct ublk_device *ub)
 {
-	if (ub->dev_info.flags & UBLK_F_USER_RECOVERY)
-		return true;
-	return false;
+	return ub->dev_info.flags & UBLK_F_USER_RECOVERY;
 }
 
 static void ublk_free_disk(struct gendisk *disk)
@@ -428,10 +422,9 @@ static const struct block_device_operations ub_fops = {
 #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;
+	unsigned long	ubuf;
+	unsigned int	len;
 };
 
 struct ublk_io_iter {
@@ -488,18 +481,17 @@ static inline unsigned ublk_copy_io_pages(struct ublk_io_iter *data,
 	return done;
 }
 
-static inline int ublk_copy_user_pages(struct ublk_map_data *data,
-		bool to_vm)
+static 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;
+	const unsigned long start_vm = data->ubuf;
 	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 +
+	const unsigned int nr_pages = round_up(data->len +
 			(start_vm & (PAGE_SIZE - 1)), PAGE_SIZE) >> PAGE_SHIFT;
 
 	while (done < nr_pages) {
@@ -512,42 +504,49 @@ static inline int ublk_copy_user_pages(struct ublk_map_data *data,
 				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);
+		len = ublk_copy_io_pages(&iter, data->len, 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;
+		data->len -= len;
 		done += iter.nr_pages;
 	}
 
 	return done;
 }
 
+static inline bool ublk_need_map_req(const struct request *req)
+{
+	return ublk_rq_has_data(req) && req_op(req) == REQ_OP_WRITE;
+}
+
+static inline bool ublk_need_unmap_req(const struct request *req)
+{
+	return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
+}
+
 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)) {
+	if (ublk_need_map_req(req)) {
 		struct ublk_map_data data = {
-			.ubq	=	ubq,
 			.rq	=	req,
-			.io	=	io,
-			.max_bytes =	rq_bytes,
+			.ubuf	=	io->addr,
+			.len	=	rq_bytes,
 		};
 
 		ublk_copy_user_pages(&data, true);
 
-		return rq_bytes - data.max_bytes;
+		return rq_bytes - data.len;
 	}
 	return rq_bytes;
 }
@@ -558,19 +557,18 @@ static int ublk_unmap_io(const struct ublk_queue *ubq,
 {
 	const unsigned int rq_bytes = blk_rq_bytes(req);
 
-	if (req_op(req) == REQ_OP_READ && ublk_rq_has_data(req)) {
+	if (ublk_need_unmap_req(req)) {
 		struct ublk_map_data data = {
-			.ubq	=	ubq,
 			.rq	=	req,
-			.io	=	io,
-			.max_bytes =	io->res,
+			.ubuf	=	io->addr,
+			.len	=	io->res,
 		};
 
 		WARN_ON_ONCE(io->res > rq_bytes);
 
 		ublk_copy_user_pages(&data, false);
 
-		return io->res - data.max_bytes;
+		return io->res - data.len;
 	}
 	return rq_bytes;
 }
@@ -655,14 +653,15 @@ 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;
+	blk_status_t res = BLK_STS_OK;
 
 	/* 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;
+		res = errno_to_blk_status(io->res);
+		goto exit;
 	}
 
 	/*
@@ -671,10 +670,8 @@ static void ublk_complete_rq(struct request *req)
 	 *
 	 * 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;
-	}
+	if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
+		goto exit;
 
 	/* for READ request, writing data in iod->addr to rq buffers */
 	unmapped_bytes = ublk_unmap_io(ubq, req, io);
@@ -691,6 +688,10 @@ static void ublk_complete_rq(struct request *req)
 		blk_mq_requeue_request(req, true);
 	else
 		__blk_mq_end_request(req, BLK_STS_OK);
+
+	return;
+exit:
+	blk_mq_end_request(req, res);
 }
 
 /*
@@ -771,9 +772,7 @@ static inline void __ublk_rq_task_work(struct request *req,
 		return;
 	}
 
-	if (ublk_need_get_data(ubq) &&
-			(req_op(req) == REQ_OP_WRITE ||
-			req_op(req) == REQ_OP_FLUSH)) {
+	if (ublk_need_get_data(ubq) && ublk_need_map_req(req)) {
 		/*
 		 * We have not handled UBLK_IO_NEED_GET_DATA command yet,
 		 * so immepdately pass UBLK_IO_RES_NEED_GET_DATA to ublksrv
@@ -900,6 +899,22 @@ static void ublk_queue_cmd(struct ublk_queue *ubq, struct request *rq)
 	}
 }
 
+static enum blk_eh_timer_return ublk_timeout(struct request *rq)
+{
+	struct ublk_queue *ubq = rq->mq_hctx->driver_data;
+
+	if (ubq->flags & UBLK_F_UNPRIVILEGED_DEV) {
+		if (!ubq->timeout) {
+			send_sig(SIGKILL, ubq->ubq_daemon, 0);
+			ubq->timeout = true;
+		}
+
+		return BLK_EH_DONE;
+	}
+
+	return BLK_EH_RESET_TIMER;
+}
+
 static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
 		const struct blk_mq_queue_data *bd)
 {
@@ -959,6 +974,7 @@ static const struct blk_mq_ops ublk_mq_ops = {
 	.queue_rq       = ublk_queue_rq,
 	.init_hctx	= ublk_init_hctx,
 	.init_request   = ublk_init_rq,
+	.timeout	= ublk_timeout,
 };
 
 static int ublk_ch_open(struct inode *inode, struct file *filp)
@@ -1019,7 +1035,7 @@ static int ublk_ch_mmap(struct file *filp, struct vm_area_struct *vma)
 }
 
 static void ublk_commit_completion(struct ublk_device *ub,
-		struct ublksrv_io_cmd *ub_cmd)
+		const 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);
@@ -1261,9 +1277,23 @@ static void ublk_handle_need_get_data(struct ublk_device *ub, int q_id,
 	ublk_queue_cmd(ubq, req);
 }
 
-static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
+static inline int ublk_check_cmd_op(u32 cmd_op)
+{
+	u32 ioc_type = _IOC_TYPE(cmd_op);
+
+	if (IS_ENABLED(CONFIG_BLKDEV_UBLK_LEGACY_OPCODES) && ioc_type != 'u')
+		return -EOPNOTSUPP;
+
+	if (ioc_type != 'u' && ioc_type != 0)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
+			       unsigned int issue_flags,
+			       const struct ublksrv_io_cmd *ub_cmd)
 {
-	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;
@@ -1302,10 +1332,15 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
 	 * iff the driver have set the UBLK_IO_FLAG_NEED_GET_DATA.
 	 */
 	if ((!!(io->flags & UBLK_IO_FLAG_NEED_GET_DATA))
-			^ (cmd_op == UBLK_IO_NEED_GET_DATA))
+			^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
+		goto out;
+
+	ret = ublk_check_cmd_op(cmd_op);
+	if (ret)
 		goto out;
 
-	switch (cmd_op) {
+	ret = -EINVAL;
+	switch (_IOC_NR(cmd_op)) {
 	case UBLK_IO_FETCH_REQ:
 		/* UBLK_IO_FETCH_REQ is only allowed before queue is setup */
 		if (ublk_queue_ready(ubq)) {
@@ -1362,6 +1397,23 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
 	return -EIOCBQUEUED;
 }
 
+static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
+{
+	/*
+	 * Not necessary for async retry, but let's keep it simple and always
+	 * copy the values to avoid any potential reuse.
+	 */
+	const struct ublksrv_io_cmd *ub_src = io_uring_sqe_cmd(cmd->sqe);
+	const struct ublksrv_io_cmd ub_cmd = {
+		.q_id = READ_ONCE(ub_src->q_id),
+		.tag = READ_ONCE(ub_src->tag),
+		.result = READ_ONCE(ub_src->result),
+		.addr = READ_ONCE(ub_src->addr)
+	};
+
+	return __ublk_ch_uring_cmd(cmd, issue_flags, &ub_cmd);
+}
+
 static const struct file_operations ublk_ch_fops = {
 	.owner = THIS_MODULE,
 	.open = ublk_ch_open,
@@ -1567,7 +1619,7 @@ static struct ublk_device *ublk_get_device_from_id(int idx)
 
 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;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 	int ublksrv_pid = (int)header->data[0];
 	struct gendisk *disk;
 	int ret = -EINVAL;
@@ -1630,7 +1682,7 @@ out_unlock:
 static int ublk_ctrl_get_queue_affinity(struct ublk_device *ub,
 		struct io_uring_cmd *cmd)
 {
-	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 	void __user *argp = (void __user *)(unsigned long)header->addr;
 	cpumask_var_t cpumask;
 	unsigned long queue;
@@ -1681,7 +1733,7 @@ static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info *info)
 
 static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
 {
-	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 	void __user *argp = (void __user *)(unsigned long)header->addr;
 	struct ublksrv_ctrl_dev_info info;
 	struct ublk_device *ub;
@@ -1703,6 +1755,18 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
 	else if (!(info.flags & UBLK_F_UNPRIVILEGED_DEV))
 		return -EPERM;
 
+	/*
+	 * unprivileged device can't be trusted, but RECOVERY and
+	 * RECOVERY_REISSUE still may hang error handling, so can't
+	 * support recovery features for unprivileged ublk now
+	 *
+	 * TODO: provide forward progress for RECOVERY handler, so that
+	 * unprivileged device can benefit from it
+	 */
+	if (info.flags & UBLK_F_UNPRIVILEGED_DEV)
+		info.flags &= ~(UBLK_F_USER_RECOVERY_REISSUE |
+				UBLK_F_USER_RECOVERY);
+
 	/* the created device is always owned by current user */
 	ublk_store_owner_uid_gid(&info.owner_uid, &info.owner_gid);
 
@@ -1752,6 +1816,8 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
 	if (!IS_BUILTIN(CONFIG_BLK_DEV_UBLK))
 		ub->dev_info.flags |= UBLK_F_URING_CMD_COMP_IN_TASK;
 
+	ub->dev_info.flags |= UBLK_F_CMD_IOCTL_ENCODE;
+
 	/* We are not ready to support zero copy */
 	ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
 
@@ -1844,7 +1910,7 @@ static int ublk_ctrl_del_dev(struct ublk_device **p_ub)
 
 static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd *cmd)
 {
-	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 
 	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,
@@ -1863,7 +1929,7 @@ static int ublk_ctrl_stop_dev(struct ublk_device *ub)
 static int ublk_ctrl_get_dev_info(struct ublk_device *ub,
 		struct io_uring_cmd *cmd)
 {
-	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 	void __user *argp = (void __user *)(unsigned long)header->addr;
 
 	if (header->len < sizeof(struct ublksrv_ctrl_dev_info) || !header->addr)
@@ -1894,7 +1960,7 @@ static void ublk_ctrl_fill_params_devt(struct ublk_device *ub)
 static int ublk_ctrl_get_params(struct ublk_device *ub,
 		struct io_uring_cmd *cmd)
 {
-	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 	void __user *argp = (void __user *)(unsigned long)header->addr;
 	struct ublk_params_header ph;
 	int ret;
@@ -1925,7 +1991,7 @@ static int ublk_ctrl_get_params(struct ublk_device *ub,
 static int ublk_ctrl_set_params(struct ublk_device *ub,
 		struct io_uring_cmd *cmd)
 {
-	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 	void __user *argp = (void __user *)(unsigned long)header->addr;
 	struct ublk_params_header ph;
 	int ret = -EFAULT;
@@ -1952,6 +2018,8 @@ static int ublk_ctrl_set_params(struct ublk_device *ub,
 		/* clear all we don't support yet */
 		ub->params.types &= UBLK_PARAM_TYPE_ALL;
 		ret = ublk_validate_params(ub);
+		if (ret)
+			ub->params.types = 0;
 	}
 	mutex_unlock(&ub->mutex);
 
@@ -1969,6 +2037,7 @@ static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq)
 	put_task_struct(ubq->ubq_daemon);
 	/* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */
 	ubq->ubq_daemon = NULL;
+	ubq->timeout = false;
 
 	for (i = 0; i < ubq->q_depth; i++) {
 		struct ublk_io *io = &ubq->ios[i];
@@ -1983,7 +2052,7 @@ static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq)
 static int ublk_ctrl_start_recovery(struct ublk_device *ub,
 		struct io_uring_cmd *cmd)
 {
-	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 	int ret = -EINVAL;
 	int i;
 
@@ -2025,7 +2094,7 @@ static int ublk_ctrl_start_recovery(struct ublk_device *ub,
 static int ublk_ctrl_end_recovery(struct ublk_device *ub,
 		struct io_uring_cmd *cmd)
 {
-	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 	int ublksrv_pid = (int)header->data[0];
 	int ret = -EINVAL;
 
@@ -2092,7 +2161,7 @@ exit:
 static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub,
 		struct io_uring_cmd *cmd)
 {
-	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)io_uring_sqe_cmd(cmd->sqe);
 	bool unprivileged = ub->dev_info.flags & UBLK_F_UNPRIVILEGED_DEV;
 	void __user *argp = (void __user *)(unsigned long)header->addr;
 	char *dev_path = NULL;
@@ -2108,7 +2177,7 @@ static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub,
 		 * know if the specified device is created as unprivileged
 		 * mode.
 		 */
-		if (cmd->cmd_op != UBLK_CMD_GET_DEV_INFO2)
+		if (_IOC_NR(cmd->cmd_op) != UBLK_CMD_GET_DEV_INFO2)
 			return 0;
 	}
 
@@ -2134,7 +2203,7 @@ static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub,
 	dev_path[header->dev_path_len] = 0;
 
 	ret = -EINVAL;
-	switch (cmd->cmd_op) {
+	switch (_IOC_NR(cmd->cmd_op)) {
 	case UBLK_CMD_GET_DEV_INFO:
 	case UBLK_CMD_GET_DEV_INFO2:
 	case UBLK_CMD_GET_QUEUE_AFFINITY:
@@ -2171,8 +2240,9 @@ exit:
 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;
+	const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
 	struct ublk_device *ub = NULL;
+	u32 cmd_op = cmd->cmd_op;
 	int ret = -EINVAL;
 
 	if (issue_flags & IO_URING_F_NONBLOCK)
@@ -2183,22 +2253,22 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
 	if (!(issue_flags & IO_URING_F_SQE128))
 		goto out;
 
-	if (cmd->cmd_op != UBLK_CMD_ADD_DEV) {
+	ret = ublk_check_cmd_op(cmd_op);
+	if (ret)
+		goto out;
+
+	if (_IOC_NR(cmd_op) != UBLK_CMD_ADD_DEV) {
 		ret = -ENODEV;
 		ub = ublk_get_device_from_id(header->dev_id);
 		if (!ub)
 			goto out;
 
 		ret = ublk_ctrl_uring_cmd_permission(ub, cmd);
-	} else {
-		/* ADD_DEV permission check is done in command handler */
-		ret = 0;
+		if (ret)
+			goto put_dev;
 	}
 
-	if (ret)
-		goto put_dev;
-
-	switch (cmd->cmd_op) {
+	switch (_IOC_NR(cmd_op)) {
 	case UBLK_CMD_START_DEV:
 		ret = ublk_ctrl_start_dev(ub, cmd);
 		break;
@@ -2272,7 +2342,7 @@ static int __init ublk_init(void)
 	if (ret)
 		goto unregister_mis;
 
-	ublk_chr_class = class_create(THIS_MODULE, "ublk-char");
+	ublk_chr_class = class_create("ublk-char");
 	if (IS_ERR(ublk_chr_class)) {
 		ret = PTR_ERR(ublk_chr_class);
 		goto free_chrdev_region;