Re: [PATCH 2/2] migration/multifd: Drop registered_yank

[Peter Xu <peterx@redhat.com>]

On Thu, Feb 08, 2024 at 09:48:33AM -0300, Fabiano Rosas wrote:
> peterx@redhat.com writes:
> 
> > From: Peter Xu <peterx@redhat.com>
> >
> > With a clear definition of p->c protocol, where we only set it up if the
> > channel is fully established (TLS or non-TLS), registered_yank boolean will
> > have equal meaning of "p->c != NULL".
> >
> > Drop registered_yank by checking p->c instead.
> >
> > Reviewed-by: Fabiano Rosas <farosas@suse.de>
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >  migration/multifd.h | 2 --
> >  migration/multifd.c | 7 +++----
> >  2 files changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/migration/multifd.h b/migration/multifd.h
> > index 8a1cad0996..b3fe27ae93 100644
> > --- a/migration/multifd.h
> > +++ b/migration/multifd.h
> > @@ -78,8 +78,6 @@ typedef struct {
> >      bool tls_thread_created;
> >      /* communication channel */
> >      QIOChannel *c;
> > -    /* is the yank function registered */
> > -    bool registered_yank;
> >      /* packet allocated len */
> >      uint32_t packet_len;
> >      /* guest page size */
> > diff --git a/migration/multifd.c b/migration/multifd.c
> > index 4a85a6b7b3..278453cf84 100644
> > --- a/migration/multifd.c
> > +++ b/migration/multifd.c
> > @@ -648,11 +648,11 @@ static int multifd_send_channel_destroy(QIOChannel *send)
> >  
> >  static bool multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp)
> >  {
> > -    if (p->registered_yank) {
> > +    if (p->c) {
> >          migration_ioc_unregister_yank(p->c);
> > +        multifd_send_channel_destroy(p->c);
> 
> At socket_send_channel_destroy the clean up of outgoing_args.saddr will
> now be skipped. The failure at multifd_new_send_channel_async might have
> been due to TLS, in which case all of plain socket setup will have
> happened properly.

Right, IMHO it's a hack to free globals in a per-channel helper.  We should
have moved:

    if (outgoing_args.saddr) {
        qapi_free_SocketAddress(outgoing_args.saddr);
        outgoing_args.saddr = NULL;
    }

Outside irrelevant of that..

That could be done later I guess, because we have one more guard:

socket_start_outgoing_migration():
    /* in case previous migration leaked it */
    qapi_free_SocketAddress(outgoing_args.saddr);
    outgoing_args.saddr = addr;

If you think proper, I can add one more patch to do that cleanup, IOW, move
above free() into multifd_send_cleanup_state().

Thanks,

-- 
Peter Xu