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/rpc/svc_dg.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) (limited to 'sys/rpc/svc_dg.c') diff --git a/sys/rpc/svc_dg.c b/sys/rpc/svc_dg.c index 72721b0..0747d1d 100644 --- a/sys/rpc/svc_dg.c +++ b/sys/rpc/svc_dg.c @@ -68,7 +68,7 @@ static bool_t svc_dg_reply(SVCXPRT *, struct rpc_msg *, struct sockaddr *, struct mbuf *); static void svc_dg_destroy(SVCXPRT *); static bool_t svc_dg_control(SVCXPRT *, const u_int, void *); -static void svc_dg_soupcall(struct socket *so, void *arg, int waitflag); +static int svc_dg_soupcall(struct socket *so, void *arg, int waitflag); static struct xp_ops svc_dg_ops = { .xp_recv = svc_dg_recv, @@ -133,9 +133,7 @@ svc_dg_create(SVCPOOL *pool, struct socket *so, size_t sendsize, xprt_register(xprt); SOCKBUF_LOCK(&so->so_rcv); - so->so_upcallarg = xprt; - so->so_upcall = svc_dg_soupcall; - so->so_rcv.sb_flags |= SB_UPCALL; + soupcall_set(so, SO_RCV, svc_dg_soupcall, xprt); SOCKBUF_UNLOCK(&so->so_rcv); return (xprt); @@ -205,9 +203,7 @@ svc_dg_recv(SVCXPRT *xprt, struct rpc_msg *msg, if (error) { SOCKBUF_LOCK(&xprt->xp_socket->so_rcv); - xprt->xp_socket->so_upcallarg = NULL; - xprt->xp_socket->so_upcall = NULL; - xprt->xp_socket->so_rcv.sb_flags &= ~SB_UPCALL; + soupcall_clear(xprt->xp_socket, SO_RCV); SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv); xprt_inactive(xprt); sx_xunlock(&xprt->xp_lock); @@ -275,9 +271,7 @@ svc_dg_destroy(SVCXPRT *xprt) { SOCKBUF_LOCK(&xprt->xp_socket->so_rcv); - xprt->xp_socket->so_upcallarg = NULL; - xprt->xp_socket->so_upcall = NULL; - xprt->xp_socket->so_rcv.sb_flags &= ~SB_UPCALL; + soupcall_clear(xprt->xp_socket, SO_RCV); SOCKBUF_UNLOCK(&xprt->xp_socket->so_rcv); sx_destroy(&xprt->xp_lock); @@ -300,10 +294,11 @@ svc_dg_control(xprt, rq, in) return (FALSE); } -static void +static int svc_dg_soupcall(struct socket *so, void *arg, int waitflag) { SVCXPRT *xprt = (SVCXPRT *) arg; xprt_active(xprt); + return (SU_OK); } -- cgit v1.1