Re:[PATCH] vdpa: regist vhost-vdpa dev class

[wang.yi59]

Hi Stefano,

Thanks for your quick reply and review, :)

> On Thu, Dec 23, 2021 at 03:31:45PM +0800, Yi Wang wrote:
> >From: Zhang Min <zhang.min9@xxxxxxxxxx>
> >
> >Some applications like kata-containers need to acquire MAJOR/MINOR/DEVNAME
> >for devInfo [1], so regist vhost-vdpa dev class to expose uevent.
> >
> >1. https://github.com/kata-containers/kata-containers/blob/main/src/runtime/virtcontainers/device/config/config.go
> >
> >Signed-off-by: Zhang Min <zhang.min9@xxxxxxxxxx>
> >Signed-off-by: Yi Wang <wang.yi59@xxxxxxxxxx>
> >---
> > drivers/vhost/vdpa.c | 12 ++++++++++++
> > 1 file changed, 12 insertions(+)
> >
> >diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> >index fb41db3da611..90fbad93e7a2 100644
> >--- a/drivers/vhost/vdpa.c
> >+++ b/drivers/vhost/vdpa.c

..

> >+    vhost_vdpa_class = class_create(THIS_MODULE, "vhost-vdpa");
> >+    if (IS_ERR(vhost_vdpa_class)) {
> >+        r = PTR_ERR(vhost_vdpa_class);
> >+        pr_warn("vhost vdpa class create error %d,  maybe mod reinserted\n", r);
>                                                            ^
> double space.
> 
> I'm not a native speaker, but I would rephrase the second part to "maybe 
> the module is already loaded"
> 
> >+        vhost_vdpa_class = NULL;
> >+        return r;
> >+    }
> >+
> >     r = alloc_chrdev_region(&vhost_vdpa_major, 0, VHOST_VDPA_DEV_MAX,
> >                 "vhost-vdpa");
> >     if (r)
> >@@ -1111,6 +1121,7 @@ static int __init vhost_vdpa_init(void)
> > err_vdpa_register_driver:
> >     unregister_chrdev_region(vhost_vdpa_major, VHOST_VDPA_DEV_MAX);
> > err_alloc_chrdev:
> >+    class_destroy(vhost_vdpa_class);
> 
> Should we set `vhost_vdpa_class` to NULL here?
> 
> If yes, maybe better to add a new label, and a goto in the 
> `class_create` error handling.

Yes, reset to NULL is unnecessary, and pr_warn will not be reached when module
is already loaded, so it's no need too.
There will be a v2 patch which simply return PTR_ERR(vhost_vdpa_class);
Other suggestions are also accepted. 

> >     return r;
> > }