Re: [PATCH v4 1/5] vfio/migration: Add debugfs to live migration driver

Jason Gunthorpe
2022-12-05T13:55:18Z

On Mon, Dec 05, 2022 at 09:39:29PM +0800, liulongfang wrote:
> On 2022/12/2 23:17, Jason Gunthorpe wrote:
> > On Fri, Dec 02, 2022 at 05:26:21PM +0800, Longfang Liu wrote:
> >
> >> +static ssize_t vfio_pci_vf_state_read(struct file *filp, char __user *buffer,
> >> + size_t count, loff_t *pos)
> >> +{
> >
> > This would be better to use debugfs_create_devm_seqfile()
> >
> > Then you can simply use seq_printf()
> >
>
> The previous debugfs used this method in my patch.
> Is it now recommended to use the interface with "devm" ?

It doesn't matter, the point is not the devm, it is to use the right
helper for the data you want to expose over debugfs

> >> @@ -119,6 +129,8 @@ struct vfio_migration_ops {
> >> enum vfio_device_mig_state *curr_state);
> >> int (*migration_get_data_size)(struct vfio_device *device,
> >> unsigned long *stop_copy_length);
> >> + int (*migration_get_data)(struct vfio_device *device, char *buffer);
> >> + int (*migration_get_attr)(struct vfio_device *device, char
> >> *buffer);
> >
> > Still no to passing through debugfs ops, create these files in the
> > driver.
> >
>
> If this part is also created and enabled in the device driver, why do we need
> to put this debugfs in the vfio public framework?

To create the directory, and the few actually common files

Jason