Re: [PATCH 1/1] NVMe: Do not take nsid while a passthrough IO command is being issued via a block device file descriptor

Christoph Hellwig
2015-01-25T14:59:02Z

On Fri, Jan 23, 2015 at 03:57:06PM -0800, Yan Liu wrote:
> When a passthrough IO command is issued with a specific block device file descriptor. It should be applied at
> the namespace which is associated with that block device file descriptor. This patch makes such passthrough
> command ignore nsid in nvme_passthru_cmd structure. Instead it takes the namespace ID asscoiated with the
> block device descriptor.

This looks good to me. If Keith can point to a use case for magic or
hidden nsids we'll have to find a bypass for them, but this certainly
is the right short term fix:

Reviewed-by: Christoph Hellwig <hch@lst.de>

> {
> struct nvme_dev *dev = f->private_data;
> struct nvme_ns *ns;
> + int ret;
>
> switch (cmd) {
> case NVME_IOCTL_ADMIN_CMD:
> return nvme_user_cmd(dev, NULL, (void __user *)arg);
> case NVME_IOCTL_IO_CMD:
> - if (list_empty(&dev->namespaces))
> - return -ENOTTY;
> - ns = list_first_entry(&dev->namespaces, struct nvme_ns, list);
> + ret = nvme_namespace_sel(dev, &ns, (void __user *)arg);
> + if (ret)
> + return ret;
> return nvme_user_cmd(dev, ns, (void __user *)arg);
> default:

This function would benefit from a local variable ala:

void __user *argp = (void __user *)arg;

but that might be done in a follow up patch, or postponed for now.