Re: [PATCH] examples/ntb: remove redundant logic for dev close

[Thomas Monjalon <thomas@monjalon.net>]

28/06/2023 04:37, Guo, Junfeng:
> From: Guo, Junfeng
> > From: Thomas Monjalon <thomas@monjalon.net>
> > > 14/06/2023 07:14, Junfeng Guo:
> > > > During EAL cleanup stage, all bus devices are cleaned up properly.
> > > > Based on this, there is no need to do extra device close process,
> > > > which may call the dev ops '*dev->dev_ops->dev_close' twice.
> > > >
> > > > If this dev ops for ntb was called twice, the interrupt handle for
> > > > EAL will be disabled twice and will lead to error for the seconde
> > > > time. Like this: "EAL: Error disabling MSI-X interrupts for fd xx"
> > >
> > > You should fix ntb to not disable interrupt twice.
> > 
> > Thanks for the comment!
> > 
> > Yes, it is exactly what this patch did.
> 
> Another solution is to add extra logic in dev_close, i.e., to do the
> interrupt disabling process only when the interrupt handler is valid.
> That is, to disable interrupt only when 'intr_handle->max_intr' or
> 'intr_handle->nb_efd' is non-zero.
> 
> But I'm not sure if this method is a better solution.
> Please help give some advice, thanks!

Yes this is what I suggest.
You cannot fix all applications in the world,
but you can fix the driver, so it is a better way :)

> > The interrupt disabling process is part of 'dev_close' ops, and will be
> > called twice (one in EAL cleanup, another in ntb example cleanup).
> > 
> > Now that fixed & covered by the EAL cleanup, there is no need to
> > run dev_close at ntb example. Just remove that redundant logic.