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From:
Alexander Bluhm <alexander.bluhm@gmx.net>
Subject:
Re: Push solock() down to sobind()
To:
Vitaliy Makkoveev <mvs@openbsd.org>
Cc:
tech@openbsd.org
Date:
Fri, 19 Jan 2024 15:17:30 +0100

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On Tue, Jan 09, 2024 at 03:39:33PM +0100, Alexander Bluhm wrote:
> On Tue, Jan 09, 2024 at 04:17:27PM +0300, Vitaliy Makkoveev wrote:
> > All existing sobind() calls are only wrapped by solock(). So push it
> > down and convert to solock_shared() to make identical to sys_bind().
> > solock_shared() makes senses because the most of these sockets are
> > UDP sockets.
> 
> Changing to solock_shared() for NFS is risky.
> 
> I would prefer to do the solock_shared() conversion step by step
> with proper review of the sub system.  Then pushing the lock down
> to sobind() will be mechanical.

I had a look at all the sub systems.  Most have their own locking.
NFS uses kernel lock so everything is serialized.

OK bluhm@

> > Index: sys/kern/uipc_socket.c
> > ===================================================================
> > RCS file: /cvs/src/sys/kern/uipc_socket.c,v
> > retrieving revision 1.312
> > diff -u -p -r1.312 uipc_socket.c
> > --- sys/kern/uipc_socket.c	19 Dec 2023 21:34:22 -0000	1.312
> > +++ sys/kern/uipc_socket.c	9 Jan 2024 13:08:15 -0000
> > @@ -219,8 +219,13 @@ socreate(int dom, struct socket **aso, i
> >  int
> >  sobind(struct socket *so, struct mbuf *nam, struct proc *p)
> >  {
> > -	soassertlocked(so);
> > -	return pru_bind(so, nam, p);
> > +	int error;
> > +
> > +	solock_shared(so);
> > +	error = pru_bind(so, nam, p);
> > +	sounlock_shared(so);
> > +
> > +	return (error);
> >  }
> >  
> >  int
> > Index: sys/kern/uipc_syscalls.c
> > ===================================================================
> > RCS file: /cvs/src/sys/kern/uipc_syscalls.c,v
> > retrieving revision 1.216
> > diff -u -p -r1.216 uipc_syscalls.c
> > --- sys/kern/uipc_syscalls.c	3 Jan 2024 11:07:04 -0000	1.216
> > +++ sys/kern/uipc_syscalls.c	9 Jan 2024 13:08:15 -0000
> > @@ -185,9 +185,7 @@ sys_bind(struct proc *p, void *v, regist
> >  	if (KTRPOINT(p, KTR_STRUCT))
> >  		ktrsockaddr(p, mtod(nam, caddr_t), SCARG(uap, namelen));
> >  #endif
> > -	solock_shared(so);
> >  	error = sobind(so, nam, p);
> > -	sounlock_shared(so);
> >  	m_freem(nam);
> >  out:
> >  	FRELE(fp, p);
> > Index: sys/net/bfd.c
> > ===================================================================
> > RCS file: /cvs/src/sys/net/bfd.c,v
> > retrieving revision 1.80
> > diff -u -p -r1.80 bfd.c
> > --- sys/net/bfd.c	3 Aug 2023 09:49:08 -0000	1.80
> > +++ sys/net/bfd.c	9 Jan 2024 13:08:15 -0000
> > @@ -477,9 +477,7 @@ bfd_listener(struct bfd_config *bfd, uns
> >  		break;
> >  	}
> >  
> > -	solock(so);
> >  	error = sobind(so, m, p);
> > -	sounlock(so);
> >  	if (error) {
> >  		printf("%s: sobind error %d\n",
> >  		    __func__, error);
> > @@ -578,9 +576,7 @@ bfd_sender(struct bfd_config *bfd, unsig
> >  		break;
> >  	}
> >  
> > -	solock(so);
> >  	error = sobind(so, m, p);
> > -	sounlock(so);
> >  	if (error) {
> >  		printf("%s: sobind error %d\n",
> >  		    __func__, error);
> > Index: sys/net/if_pflow.c
> > ===================================================================
> > RCS file: /cvs/src/sys/net/if_pflow.c,v
> > retrieving revision 1.109
> > diff -u -p -r1.109 if_pflow.c
> > --- sys/net/if_pflow.c	23 Dec 2023 10:52:54 -0000	1.109
> > +++ sys/net/if_pflow.c	9 Jan 2024 13:08:15 -0000
> > @@ -467,9 +467,7 @@ pflow_set(struct pflow_softc *sc, struct
> >  				memcpy(sa, sc->sc_flowsrc,
> >  				    sc->sc_flowsrc->sa_len);
> >  
> > -				solock(so);
> >  				error = sobind(so, m, p);
> > -				sounlock(so);
> >  				m_freem(m);
> >  				if (error) {
> >  					soclose(so, MSG_DONTWAIT);
> > Index: sys/net/if_vxlan.c
> > ===================================================================
> > RCS file: /cvs/src/sys/net/if_vxlan.c,v
> > retrieving revision 1.99
> > diff -u -p -r1.99 if_vxlan.c
> > --- sys/net/if_vxlan.c	23 Dec 2023 10:52:54 -0000	1.99
> > +++ sys/net/if_vxlan.c	9 Jan 2024 13:08:15 -0000
> > @@ -972,9 +972,7 @@ vxlan_tep_add_addr(struct vxlan_softc *s
> >  		unhandled_af(vt->vt_af);
> >  	}
> >  
> > -	solock(so);
> >  	error = sobind(so, &m, curproc);
> > -	sounlock(so);
> >  	if (error != 0)
> >  		goto close;
> >  
> > Index: sys/net/if_wg.c
> > ===================================================================
> > RCS file: /cvs/src/sys/net/if_wg.c,v
> > retrieving revision 1.35
> > diff -u -p -r1.35 if_wg.c
> > --- sys/net/if_wg.c	1 Jan 2024 18:47:02 -0000	1.35
> > +++ sys/net/if_wg.c	9 Jan 2024 13:08:15 -0000
> > @@ -734,12 +734,11 @@ wg_socket_open(struct socket **so, int a
> >  	sounlock(*so);
> >  
> >  	if ((ret = sosetopt(*so, SOL_SOCKET, SO_RTABLE, &mrtable)) == 0) {
> > -		solock(*so);
> >  		if ((ret = sobind(*so, &mhostnam, curproc)) == 0) {
> > +			/* No lock required. Immutable for this socket. */
> >  			*port = sotoinpcb(*so)->inp_lport;
> >  			*rtable = sotoinpcb(*so)->inp_rtableid;
> >  		}
> > -		sounlock(*so);
> >  	}
> >  
> >  	if (ret != 0)
> > Index: sys/nfs/krpc_subr.c
> > ===================================================================
> > RCS file: /cvs/src/sys/nfs/krpc_subr.c,v
> > retrieving revision 1.38
> > diff -u -p -r1.38 krpc_subr.c
> > --- sys/nfs/krpc_subr.c	3 Aug 2023 09:49:09 -0000	1.38
> > +++ sys/nfs/krpc_subr.c	9 Jan 2024 13:08:15 -0000
> > @@ -280,9 +280,7 @@ krpc_call(struct sockaddr_in *sa, u_int 
> >  	sin->sin_family = AF_INET;
> >  	sin->sin_addr.s_addr = INADDR_ANY;
> >  	sin->sin_port = htons(0);
> > -	solock(so);
> >  	error = sobind(so, m, &proc0);
> > -	sounlock(so);
> >  	m_freem(m);
> >  	if (error) {
> >  		printf("bind failed\n");
> > Index: sys/nfs/nfs_socket.c
> > ===================================================================
> > RCS file: /cvs/src/sys/nfs/nfs_socket.c,v
> > retrieving revision 1.144
> > diff -u -p -r1.144 nfs_socket.c
> > --- sys/nfs/nfs_socket.c	3 Aug 2023 09:49:09 -0000	1.144
> > +++ sys/nfs/nfs_socket.c	9 Jan 2024 13:08:15 -0000
> > @@ -281,9 +281,7 @@ nfs_connect(struct nfsmount *nmp, struct
> >  		sin->sin_family = AF_INET;
> >  		sin->sin_addr.s_addr = INADDR_ANY;
> >  		sin->sin_port = htons(0);
> > -		solock(so);
> >  		error = sobind(so, nam, &proc0);
> > -		sounlock(so);
> >  		if (error)
> >  			goto bad;
> >