Re: [PATCH v2 2/2] Drivers: hv: vmbus: Fix rescind handling in uio_hv_generic

[Wei Liu]

On Thu, Sep 05, 2024 at 07:30:10AM +0000, Wei Liu wrote:
> On Thu, Aug 29, 2024 at 06:40:16AM -0700, Saurabh Singh Sengar wrote:
> > On Thu, Aug 29, 2024 at 12:43:12PM +0530, Naman Jain wrote:
> > > Rescind offer handling relies on rescind callbacks for some of the
> > > resources cleanup, if they are registered. It does not unregister
> > > vmbus device for the primary channel closure, when callback is
> > > registered. Without it, next onoffer does not come, rescind flag
> > > remains set and device goes to unusable state.
> > > 
> > > Add logic to unregister vmbus for the primary channel in rescind callback
> > > to ensure channel removal and relid release, and to ensure that next
> > > onoffer can be received and handled properly.
> > > 
> > > Cc: stable@xxxxxxxxxxxxxxx
> > > Fixes: ca3cda6fcf1e ("uio_hv_generic: add rescind support")
> > > Signed-off-by: Naman Jain <namjain@xxxxxxxxxxxxxxxxxxx>
> > > ---
> > >  drivers/hv/vmbus_drv.c       | 1 +
> > >  drivers/uio/uio_hv_generic.c | 8 ++++++++
> > >  2 files changed, 9 insertions(+)
> > > 
> > > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> > > index 7242c4920427..c405295b930a 100644
> > > --- a/drivers/hv/vmbus_drv.c
> > > +++ b/drivers/hv/vmbus_drv.c
> > > @@ -1980,6 +1980,7 @@ void vmbus_device_unregister(struct hv_device *device_obj)
> > >  	 */
> > >  	device_unregister(&device_obj->device);
> > >  }
> > > +EXPORT_SYMBOL_GPL(vmbus_device_unregister);
> > >  
> > >  #ifdef CONFIG_ACPI
> > >  /*
> > > diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
> > > index e3e66a3e85a8..870409599411 100644
> > > --- a/drivers/uio/uio_hv_generic.c
> > > +++ b/drivers/uio/uio_hv_generic.c
> > > @@ -121,6 +121,14 @@ static void hv_uio_rescind(struct vmbus_channel *channel)
> > >  
> > >  	/* Wake up reader */
> > >  	uio_event_notify(&pdata->info);
> > > +
> > > +	/*
> > > +	 * With rescind callback registered, rescind path will not unregister the device
> > > +	 * from vmbus when the primary channel is rescinded.
> > > +	 * Without it, rescind handling is incomplete and next onoffer msg does not come.
> > > +	 * Unregister the device from vmbus here.
> > > +	 */
> > > +	vmbus_device_unregister(channel->device_obj);
> > >  }
> > >  
> > >  /* Sysfs API to allow mmap of the ring buffers
> > > -- 
> > > 2.34.1
> > >
> > 
> > For the series,
> > Reviewed-by: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx> 
> 
> Applied to hyperv-fixes, thanks.

Since Greg has already applied this series, I am dropping them from my
tree.

> 
> >