[PATCH 3/4] nvme: fixes for NVME_IOCTL_IO_CMD on the char device

[Keith Busch]

On Thu, Dec 24, 2015 at 03:27:01PM +0100, Christoph Hellwig wrote:
> Make sure we synchronize access to the namespaces list and grab a reference
> to the namespace before doing I/O.  Make sure to reject the ioctl if multiple
> namespaces are present as it's entirely unsafe, and warn when using it even
> with a single namespace.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> Reviewed-by: Sagi Grimberg <sagig at mellanox.com>

Okay, I accept the argument for allowing these to "hidden" namespaces
is not sufficiently justified.

Acked-by: Keith Busch <keith.busch at intel.com>