Re: [PATCH v2] Drivers: vmbus: Check for channel allocation before looking up relids

[Mohammed Gamal]

On Fri, Feb 17, 2023 at 8:25 AM Dexuan Cui <decui@xxxxxxxxxxxxx> wrote:
>
> > From: Mohammed Gamal <mgamal@xxxxxxxxxx>
> > Sent: Tuesday, February 14, 2023 3:28 AM
> > ...
> > So Make relid2channel() check if vmbus channels is allocated first, and if not
> > print a warning and return NULL to the caller.
> Can we change the above to:
>
> Print a warning and error out in relid2channel() for a channel id that's invalid
> in the second kernel.
Will do!

>
> > --- a/drivers/hv/connection.c
> > +++ b/drivers/hv/connection.c
> > @@ -409,6 +409,10 @@ void vmbus_disconnect(void)
> >   */
> >  struct vmbus_channel *relid2channel(u32 relid)
> >  {
> > +     if (vmbus_connection.channels == NULL) {
> > +             WARN(1, "Requested relid=%u, but channel mapping not
> > allocated!\n", relid);
>
> WARN() may be too noisy. I suggest we use pr_warn() instead.
>
Makes sense. Will use pr_warn() instead.

> Can we make the line a little shorter:
>         pr_warn("relid2channel: invalid channel id %u\n", relid);
>
I think this message could be a bit misleading. The problem here is
not that the relid
is invalid, but that the relid-to-channel mapping hasn't been
allocated by the second
kernel yet. An invalid relid could simply be the case where relid >=
MAX_CHANNEL_RELIDS.

May be something like:
     pr_warn("relid2channel: No channels mapped for relid %d\n, relid");
would be clearer?