[PATCH] raw/ntb: add check for DB intr handler registering

[Guo, Junfeng]

> -----Original Message-----
> From: Wu, Jingjing <jingjing.wu at intel.com>
> Sent: Thursday, February 10, 2022 15:05
> To: Guo, Junfeng <junfeng.guo at intel.com>
> Cc: dev at dpdk.org; stable at dpdk.org
> Subject: RE: [PATCH] raw/ntb: add check for DB intr handler registering
> 
> 
> 
> > -----Original Message-----
> > From: Guo, Junfeng <junfeng.guo at intel.com>
> > Sent: Thursday, February 10, 2022 2:29 PM
> > To: Wu, Jingjing <jingjing.wu at intel.com>
> > Cc: dev at dpdk.org; stable at dpdk.org; Guo, Junfeng
> <junfeng.guo at intel.com>
> > Subject: [PATCH] raw/ntb: add check for DB intr handler registering
> >
> > The callback registering of doorbell interrupt handler should be
> > finished before enabling the interrupt event fd. Thus add the return
> > value check for this callback registering.
> >
> > Fixes: 62012a76811e ("raw/ntb: add handshake process")
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Junfeng Guo <junfeng.guo at intel.com>
> > ---
> >  drivers/raw/ntb/ntb.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/raw/ntb/ntb.c b/drivers/raw/ntb/ntb.c
> > index cc611dfbb9..0801e6d1ae 100644
> > --- a/drivers/raw/ntb/ntb.c
> > +++ b/drivers/raw/ntb/ntb.c
> > @@ -1403,8 +1403,12 @@ ntb_init_hw(struct rte_rawdev *dev, struct
> rte_pci_device
> > *pci_dev)
> >
> >  	intr_handle = pci_dev->intr_handle;
> >  	/* Register callback func to eal lib */
> > -	rte_intr_callback_register(intr_handle,
> > -				   ntb_dev_intr_handler, dev);
> > +	ret = rte_intr_callback_register(intr_handle,
> > +					 ntb_dev_intr_handler, dev);
> > +	if (ret) {
> > +		NTB_LOG(ERR, "Unable to register doorbell intr
> handler.");
> > +		return ret;
> > +	}
> When will this register failure happen? Have you checked what is the root
> cause?

When bind with vfio-pci, the DB interrupt callback function often cannot work as expected.
I think this is due to that, the intr callback registering not finished before event fd enabled.
Add the check of the return value here can make sure about correct processing sequence.

> 
> >
> >  	ret = rte_intr_efd_enable(intr_handle, hw->db_cnt);
> >  	if (ret)
> Need roll back, such as rte_intr_callback_unregister is required when fail
> or driver remove?
> > --
> > 2.25.1