Received-SPF: pass (google.com: domain of linux-kernel+bounces-188073-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Precedence: bulk
MIME-Version: 1.0
References: <20240318194902.3290795-1-khazhy@google.com> <20240318194902.3290795-2-khazhy@google.com>
 <6bc61553-6c8e-4705-9cbb-8e73d3f8c801@oracle.com>
In-Reply-To: <6bc61553-6c8e-4705-9cbb-8e73d3f8c801@oracle.com>
From: Khazhy Kumykov <khazhy@chromium.org>
Date: Thu, 23 May 2024 15:25:09 -0700
Message-ID: <CACGdZYKihs6Zfc9vpN5LrFVwx7+qqxV-cMzsO8=cpXpFYWt6ig@mail.gmail.com>
Subject: Re: [PATCH 2/2] iscsi_tcp: disallow binding the same connection twice
To: Mike Christie <michael.christie@oracle.com>
Cc: Lee Duncan <lduncan@suse.com>, Chris Leech <cleech@redhat.com>, 
	"James E . J . Bottomley" <jejb@linux.ibm.com>, "Martin K . Petersen" <martin.petersen@oracle.com>, 
	open-iscsi@googlegroups.com, linux-scsi@vger.kernel.org, 
	linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Tue, Mar 19, 2024 at 12:34=E2=80=AFPM Mike Christie
<michael.christie@oracle.com> 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@google.com>
> > ---
> >  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 *cl=
s_session,
> >       struct socket *sock;
> >       int err;
> >
> > +     if (tcp_sw_conn->sock)
> > +             return -EINVAL;
> > +
> >       /* lookup for existing socket */
> >       sock =3D sockfd_lookup((int)transport_eph, &err);
> >       if (!sock) {
>