Re: [PATCH] nvme: Add module reference counting for multipath nvme device

[Wen Xiong <wenxiong@linux.ibm.com>]

On 2026-08-11 15:49, Keith Busch wrote:

> Let's say one path is rdma and the other is tcp. At the time you open,
> the RDMA is the current optimal path, so you take a reference on the
> nvme-rdma module. But while using this multipath device, the RDMA
> connection is lost, so we failover to the TCP path. When you close the
> multipath device, you find the TCP path, and then drop a reference on
> the nvme-tcp module, leaking the RDMA reference, and underflowing TCP.

Thanks for explaining this!

> Just a note, unlike I initially thought, nvme_mpath_remove_disk() is 
> not
> the mirror teardown function to nvme_mpath_add_disk(), so the path's
> module reference put will have to be somewhere else, like
> nvme_mpath_remove_sysfs_link().

Thanks! I can regenerate the patch as v2 and test it soon.
Can I add module reference get in nvme_mpath_add_sysfs_link() instead of 
nvme_mpath_add_disk()?

Thanks,
Wendy