From a1af9ecca44f362b24fe3a8342ca6ed8676a399c Mon Sep 17 00:00:00 2001 From: jhb Date: Mon, 1 Jun 2009 21:17:03 +0000 Subject: Rework socket upcalls to close some races with setup/teardown of upcalls. - Each socket upcall is now invoked with the appropriate socket buffer locked. It is not permissible to call soisconnected() with this lock held; however, so socket upcalls now return an integer value. The two possible values are SU_OK and SU_ISCONNECTED. If an upcall returns SU_ISCONNECTED, then the soisconnected() will be invoked on the socket after the socket buffer lock is dropped. - A new API is provided for setting and clearing socket upcalls. The API consists of soupcall_set() and soupcall_clear(). - To simplify locking, each socket buffer now has a separate upcall. - When a socket upcall returns SU_ISCONNECTED, the upcall is cleared from the receive socket buffer automatically. Note that a SO_SND upcall should never return SU_ISCONNECTED. - All this means that accept filters should now return SU_ISCONNECTED instead of calling soisconnected() directly. They also no longer need to explicitly clear the upcall on the new socket. - The HTTP accept filter still uses soupcall_set() to manage its internal state machine, but other accept filters no longer have any explicit knowlege of socket upcall internals aside from their return value. - The various RPC client upcalls currently drop the socket buffer lock while invoking soreceive() as a temporary band-aid. The plan for the future is to add a new flag to allow soreceive() to be called with the socket buffer locked. - The AIO callback for socket I/O is now also invoked with the socket buffer locked. Previously sowakeup() would drop the socket buffer lock only to call aio_swake() which immediately re-acquired the socket buffer lock for the duration of the function call. Discussed with: rwatson, rmacklem --- sys/netsmb/smb_trantcp.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'sys/netsmb/smb_trantcp.c') diff --git a/sys/netsmb/smb_trantcp.c b/sys/netsmb/smb_trantcp.c index 167b74b..1a74e728 100644 --- a/sys/netsmb/smb_trantcp.c +++ b/sys/netsmb/smb_trantcp.c @@ -100,14 +100,15 @@ nb_intr(struct nbpcb *nbp, struct proc *p) return 0; } -static void +static int nb_upcall(struct socket *so, void *arg, int waitflag) { struct nbpcb *nbp = arg; if (arg == NULL || nbp->nbp_selectid == NULL) - return; + return (SU_OK); wakeup(nbp->nbp_selectid); + return (SU_OK); } static int @@ -152,10 +153,8 @@ nb_connect_in(struct nbpcb *nbp, struct sockaddr_in *to, struct thread *td) if (error) return error; nbp->nbp_tso = so; - so->so_upcallarg = (caddr_t)nbp; - so->so_upcall = nb_upcall; SOCKBUF_LOCK(&so->so_rcv); - so->so_rcv.sb_flags |= SB_UPCALL; + soupcall_set(so, SO_RCV, nb_upcall, nbp); SOCKBUF_UNLOCK(&so->so_rcv); so->so_rcv.sb_timeo = (5 * hz); so->so_snd.sb_timeo = (5 * hz); -- cgit v1.1