Hi Gaetan
From: Gaëtan Rivet
> Hello Matan,
>
> On Mon, May 21, 2018 at 07:48:03PM +0000, Matan Azrad wrote:
> > The fail-safe PMD registers to RMV event for each removable sub-device
> > port in order to cleanup the sub-device resources and switch the Tx
> > sub-device directly when it is plugged-out.
> >
> > During removal time, the fail-safe PMD stops and closes the sub-device
> > but it doesn't unregister the LSC and RMV callbacks of the sub-device
> > port.
> >
> > It can lead the callbacks to be called for a port which is no more
> > associated with the fail-safe sub-device, because there is not a
> > guarantee that a sub-device gets the same port ID for each plug-in
> > process. This port, for example, may belong to another sub-device of a
> > different fail-safe device.
> >
> > Unregister the LSC and RMV callbacks for sub-devices which are not
> > used.
> >
> > Fixes: 598fb8aec6f6 ("net/failsafe: support device removal")
> > Cc: sta...@dpdk.org
> >
> > Signed-off-by: Matan Azrad <ma...@mellanox.com>
> > ---
> > drivers/net/failsafe/failsafe_ether.c | 22 ++++++++++++++++++++++
> > drivers/net/failsafe/failsafe_ops.c | 5 +++++
> > drivers/net/failsafe/failsafe_private.h | 5 +++++
> > 3 files changed, 32 insertions(+)
> >
> > V2:
> > Improve the commit log and add code comments for the new sub-dev fields
> (Ophir suggestion).
> >
> >
> > diff --git a/drivers/net/failsafe/failsafe_ether.c
> > b/drivers/net/failsafe/failsafe_ether.c
> > index 733e95d..2bbee82 100644
> > --- a/drivers/net/failsafe/failsafe_ether.c
> > +++ b/drivers/net/failsafe/failsafe_ether.c
> > @@ -260,6 +260,7 @@
> > sdev->state = DEV_ACTIVE;
> > /* fallthrough */
> > case DEV_ACTIVE:
> > + failsafe_eth_dev_unregister_callbacks(sdev);
> > rte_eth_dev_close(PORT_ID(sdev));
> > sdev->state = DEV_PROBED;
> > /* fallthrough */
> > @@ -321,6 +322,27 @@
> > }
> >
> > void
> > +failsafe_eth_dev_unregister_callbacks(struct sub_device *sdev) {
> > + if (sdev == NULL)
> > + return;
> > + if (sdev->rmv_callback) {
> > + rte_eth_dev_callback_unregister(PORT_ID(sdev),
> > + RTE_ETH_EVENT_INTR_RMV,
> > + failsafe_eth_rmv_event_callback,
> > + sdev);
> > + sdev->rmv_callback = 0;
>
> I agree with Ophir here, either the return value should not be ignored, and
> rmv_callback should only be set to 0 on success, or a proper justification
> (and
> an accompanying comment) should be given.
>
> The issue I could see is that even on error, there won't be a process to try
> again
> unregistering the callback.
>
> Maybe this could be added in failsafe_dev_remove()? Something like
>
> FOREACH_SUBDEV(sdev, i, dev) {
> if (sdev->rmv_callback && sdev->state <= DEV_PROBED)
> if (rte_eth_dev_callback_unregister(...) == 0)
> sdev->rmv_callback = 0;
> /* same for lsc_callback */
> }
>
> Does it make sense to you? Do you think this is necessary, or should we ignore
> this?
The RMV\LSC event callbacks are called from the host thread and also the
removal process is running from the host thread so I think EAGAIN is not
expected in the removal time.
Other error (EINVAL) may return again every attempt and probably points to
another critical issue.
Is a code comment for the above enough? Or you think we still need to check it?
> Thanks,
> --
> Gaëtan Rivet
> 6WIND
