[PATCH v15 5/9] nvme-core: Introduce nvme_ctrl_get_by_path()

[Christoph Hellwig]

On Thu, Jul 16, 2020 at 02:33:15PM -0600, Logan Gunthorpe wrote:
> nvme_ctrl_get_by_path() is analagous to blkdev_get_by_path() except it
> gets a struct nvme_ctrl from the path to its char dev (/dev/nvme0).
> It makes use of filp_open() to open the file and uses the private
> data to obtain a pointer to the struct nvme_ctrl. If the fops of the
> file do not match, -EINVAL is returned.
> 
> The purpose of this function is to support NVMe-OF target passthru.

This looks generally good.  However since the early days of this
patchset we've grown symbol namespaces, and the EXPORT_SYMBOL_NS_GPL
macro, which are what we really should use here and for the other
exports.