Re: [PATCH] net/9p/trans_virtio.c: decrease the refcount of 9p virtio device when removing it

Dominique Martinet
2018-08-09T01:18:47Z

piaojun wrote on Thu, Aug 09, 2018:
> > What exact kernel commit are you running?
>
> My kernel commit id 6edf1d4cb0acde, and I replace the 9p code with
> 9p-next. And I wonder if this will work well?

That is somewhere on top of 4.18-rc1 and got merged in 4.18-rc4, which
are close enough so while I can question the practice I don't see why
not.

I've just tried the following:
$ git checkout 6edf1d4cb0acde
$ git checkout martinetd/9p-next net/9p fs/9p include/net/9p
(martinetd/9p-next is 9f961802a7 as of this mail)
<make, install, reboot>
$ uname -r
4.18.0-rc1+
$ lsmod | grep -E '^9pnet_virtio' || echo "not loaded"
9pnet_virtio 32768 0
$ sudo modprobe -r 9pnet_virtio
$ lsmod | grep -E '^9pnet_virtio' || echo "not loaded"
not loaded
$ sudo modprobe 9pnet_virtio
$ sudo mount -t 9p -o debug=1,trans=virtio shm /mnt
$ ls /mnt
<stuff>
$ cat /sys/module/9pnet_virtio/drivers/virtio\:9pnet_virtio/*/mount_tag
tmpshm (these could use a new line...)
$ sudo umount /mnt
$ sudo modprobe -r 9pnet_virtio
$ lsmod | grep -E '^9pnet_virtio' || echo "not loaded"
not loaded

The /sys/devices/pci*/*/virtio*/mount_tag files are also removed
properly; I don't see any problem.

Not being able to reproduce is fine in general, but I also get problems
when applying the patch and unloading the module multiple times so I
can't help but question this patch and think your problem lies somewhere
else.

--
Dominique