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

["Guo, Junfeng" <junfeng.guo@intel.com>]

> -----Original Message-----
> From: Guo, Junfeng
> Sent: Wednesday, June 28, 2023 10:19
> To: Thomas Monjalon <thomas@monjalon.net>; Wu, Jingjing
> <jingjing.wu@intel.com>
> Cc: dev@dpdk.org; stable@dpdk.org; He, Xingguang
> <xingguang.he@intel.com>; Laatz, Kevin <Kevin.Laatz@intel.com>;
> Richardson, Bruce <bruce.richardson@intel.com>
> Subject: RE: [PATCH] examples/ntb: remove redundant logic for dev close
> 
> 
> 
> > -----Original Message-----
> > From: Thomas Monjalon <thomas@monjalon.net>
> > Sent: Wednesday, June 28, 2023 08:12
> > To: Wu, Jingjing <jingjing.wu@intel.com>; Guo, Junfeng
> > <junfeng.guo@intel.com>
> > Cc: dev@dpdk.org; stable@dpdk.org; He, Xingguang
> > <xingguang.he@intel.com>; Laatz, Kevin <kevin.laatz@intel.com>;
> > Richardson, Bruce <bruce.richardson@intel.com>
> > Subject: Re: [PATCH] examples/ntb: remove redundant logic for dev
> close
> >
> > 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!


> 
> 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.
> 
> Regards,
> Junfeng
> 
> >