Re: [PATCH 2/2] iscsi_tcp: disallow binding the same connection twice

[Khazhy Kumykov]

On Tue, Mar 19, 2024 at 12:34 PM Mike Christie
<michael.christie@xxxxxxxxxx> wrote:
>
> On 3/18/24 2:49 PM, Khazhismel Kumykov wrote:
> > iscsi_sw_tcp_conn_bind does not check or cleanup previously bound
> > sockets, nor should we allow binding the same connection twice.
> >
>
> This looks like a problem for all the iscsi drivers.
>
> I think you could:
>
> 1. Add a check for ISCSI_CONN_FLAG_BOUND in iscsi_conn_bind.
> 2. Have iscsi_sw_tcp_conn_stop do:
>
>         /* stop xmit side */
> -       iscsi_suspend_tx(conn);
> +       iscsi_conn_unbind(cls_conn, true);
>
> to clear the flag when we clean up the conn for relogin.
>
> 3. Fix up the other iscsi drivers so they call:
>
> iscsi_conn_unbind(cls_conn, true);

I took a look, and it seems like the other drivers in-tree all use
iscsi_conn_unbind already, and iscsi_tcp is the odd one out - only
supporting stop_conn, and not setting ep_disconnect. Just swapping the
iscsi_suspend_tx call for iscsi_conn_unbind works, and makes sense to
me - but makes me wonder why we were using suspend_tx directly in the
first place.

The only other side effects I see are we set the session to failed
momentarily if we stop the conn while still logging in (iscsi_tcp will
quickly change this to _TERMINATE or _IN_RECOVERY once we hit the
stop_conn), which seems OK.


>
> in their failure paths so when they fail they clear ISCSI_CONN_FLAG_BOUND and
> iscsi_conn_bind can be called on the retry.
>
>
>
> > Signed-off-by: Khazhismel Kumykov <khazhy@xxxxxxxxxx>
> > ---
> >  drivers/scsi/iscsi_tcp.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
> > index e8ed60b777c6..8cf5dc203a82 100644
> > --- a/drivers/scsi/iscsi_tcp.c
> > +++ b/drivers/scsi/iscsi_tcp.c
> > @@ -716,6 +716,9 @@ iscsi_sw_tcp_conn_bind(struct iscsi_cls_session *cls_session,
> >       struct socket *sock;
> >       int err;
> >
> > +     if (tcp_sw_conn->sock)
> > +             return -EINVAL;
> > +
> >       /* lookup for existing socket */
> >       sock = sockfd_lookup((int)transport_eph, &err);
> >       if (!sock) {
>