nvme: enable uring-passthrough for admin commands

Add two new opcodes that userspace can use for admin commands:
NVME_URING_CMD_ADMIN : non-vectroed
NVME_URING_CMD_ADMIN_VEC : vectored variant

Wire up support when these are issued on controller node(/dev/nvmeX).
Signed-off-by: NKanchan Joshi <joshi.k@samsung.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220520090630.70394-3-joshi.k@samsung.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

drivers/nvme/host/core.c

@@ -3146,6 +3146,7 @@ static const struct file_operations nvme_dev_fops = {
 	.release	= nvme_dev_release,
 	.unlocked_ioctl	= nvme_dev_ioctl,
 	.compat_ioctl	= compat_ptr_ioctl,
+	.uring_cmd	= nvme_dev_uring_cmd,
 };
 
 static ssize_t nvme_sysfs_reset(struct device *dev,

drivers/nvme/host/ioctl.c

@@ -686,6 +686,29 @@ int nvme_ns_head_chr_uring_cmd(struct io_uring_cmd *ioucmd,
 }
 #endif /* CONFIG_NVME_MULTIPATH */
 
+int nvme_dev_uring_cmd(struct io_uring_cmd *ioucmd, unsigned int issue_flags)
+{
+	struct nvme_ctrl *ctrl = ioucmd->file->private_data;
+	int ret;
+
+	ret = nvme_uring_cmd_checks(issue_flags);
+	if (ret)
+		return ret;
+
+	switch (ioucmd->cmd_op) {
+	case NVME_URING_CMD_ADMIN:
+		ret = nvme_uring_cmd_io(ctrl, NULL, ioucmd, issue_flags, false);
+		break;
+	case NVME_URING_CMD_ADMIN_VEC:
+		ret = nvme_uring_cmd_io(ctrl, NULL, ioucmd, issue_flags, true);
+		break;
+	default:
+		ret = -ENOTTY;
+	}
+
+	return ret;
+}
+
 static int nvme_dev_user_cmd(struct nvme_ctrl *ctrl, void __user *argp)
 {
 	struct nvme_ns *ns;

drivers/nvme/host/nvme.h

@@ -787,6 +787,7 @@ int nvme_ns_chr_uring_cmd(struct io_uring_cmd *ioucmd,
 int nvme_ns_head_chr_uring_cmd(struct io_uring_cmd *ioucmd,
 		unsigned int issue_flags);
 int nvme_getgeo(struct block_device *bdev, struct hd_geometry *geo);
+int nvme_dev_uring_cmd(struct io_uring_cmd *ioucmd, unsigned int issue_flags);
 
 extern const struct attribute_group *nvme_ns_id_attr_groups[];
 extern const struct pr_ops nvme_pr_ops;

include/uapi/linux/nvme_ioctl.h

@@ -108,5 +108,7 @@ struct nvme_uring_cmd {
 /* io_uring async commands: */
 #define NVME_URING_CMD_IO	_IOWR('N', 0x80, struct nvme_uring_cmd)
 #define NVME_URING_CMD_IO_VEC	_IOWR('N', 0x81, struct nvme_uring_cmd)
+#define NVME_URING_CMD_ADMIN	_IOWR('N', 0x82, struct nvme_uring_cmd)
+#define NVME_URING_CMD_ADMIN_VEC _IOWR('N', 0x83, struct nvme_uring_cmd)
 
 #endif /* _UAPI_LINUX_NVME_IOCTL_H */