Re: [PATCH 05/17] nvme: wire-up support for async-passthru on char-device.

Sagi Grimberg
2022-03-13T21:53:53Z

> +int nvme_ns_head_chr_async_cmd(struct io_uring_cmd *ioucmd)
> +{
> + struct cdev *cdev = file_inode(ioucmd->file)->i_cdev;
> + struct nvme_ns_head *head = container_of(cdev, struct nvme_ns_head, cdev);
> + int srcu_idx = srcu_read_lock(&head->srcu);
> + struct nvme_ns *ns = nvme_find_path(head);
> + int ret = -EWOULDBLOCK;
> +
> + if (ns)
> + ret = nvme_ns_async_ioctl(ns, ioucmd);
> + srcu_read_unlock(&head->srcu, srcu_idx);
> + return ret;
> +}

No one cares that this has no multipathing capabilities what-so-ever?
despite being issued on the mpath device node?

I know we are not doing multipathing for userspace today, but this
feels like an alternative I/O interface for nvme, seems a bit cripled
with zero multipathing capabilities...