From 507f87a799cf0811ce30f0ae7f10ba19b2fd3db3 Mon Sep 17 00:00:00 2001 From: Gleb Smirnoff Date: Tue, 16 Jan 2024 10:26:10 -0800 Subject: [PATCH] sockets: retire sorflush() With removal of dom_dispose method the function boils down to two meaningful function calls: socantrcvmore() and sbrelease(). The latter is only relevant for protocols that use generic socket buffers. The socket I/O sx(9) lock acquisition in sorflush() is not relevant for shutdown(2) operation as it doesn't do any I/O that may interleave with read(2) or write(2). The socket buffer mutex acquisition inside sbrelease() is what guarantees thread safety. This sx(9) acquisition in soshutdown() can be tracked down to 4.4BSD times, where it used to be sblock(), and it was carried over through the years evolving together with sockets with no reconsideration of why do we carry it over. I can't tell if that sblock() made sense back then, but it doesn't make any today. Reviewed by: tuexen Differential Revision: https://reviews.freebsd.org/D43415 --- sys/kern/uipc_socket.c | 36 +++--------------------------------- sys/net/rtsock.c | 6 ++++-- sys/netinet/raw_ip.c | 6 ++++-- sys/netinet/sctp_usrreq.c | 6 +----- sys/netinet/tcp_usrreq.c | 6 ++++-- sys/netinet/udp_usrreq.c | 6 ++++-- sys/netinet6/raw_ip6.c | 6 ++++-- sys/sys/socketvar.h | 1 - 8 files changed, 24 insertions(+), 49 deletions(-) diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c index 1626c6a7442..65230e39e4a 100644 --- a/sys/kern/uipc_socket.c +++ b/sys/kern/uipc_socket.c @@ -95,9 +95,9 @@ * * NOTE: With regard to VNETs the general rule is that callers do not set * curvnet. Exceptions to this rule include soabort(), sodisconnect(), - * sofree() (and with that sorele(), sotryfree()), as well as sonewconn() - * and sorflush(), which are usually called from a pre-set VNET context. - * sopoll() currently does not need a VNET context to be set. + * sofree() (and with that sorele(), sotryfree()), as well as sonewconn(), + * which are usually called from a pre-set VNET context. sopoll() currently + * does not need a VNET context to be set. */ #include @@ -2971,36 +2971,6 @@ soshutdown(struct socket *so, enum shutdown_how how) return (error); } -/* - * Used by several pr_shutdown implementations that use generic socket buffers. - */ -void -sorflush(struct socket *so) -{ - int error; - - VNET_SO_ASSERT(so); - - /* - * Dislodge threads currently blocked in receive and wait to acquire - * a lock against other simultaneous readers before clearing the - * socket buffer. Don't let our acquire be interrupted by a signal - * despite any existing socket disposition on interruptable waiting. - */ - socantrcvmore(so); - - error = SOCK_IO_RECV_LOCK(so, SBL_WAIT | SBL_NOINTR); - if (error != 0) { - KASSERT(SOLISTENING(so), - ("%s: soiolock(%p) failed", __func__, so)); - return; - } - - sbrelease(so, SO_RCV); - SOCK_IO_RECV_UNLOCK(so); - -} - /* * Wrapper for Socket established helper hook. * Parameters: socket, context of the hook point, hook id. diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c index 94d5e9e4bcc..cb149f176b6 100644 --- a/sys/net/rtsock.c +++ b/sys/net/rtsock.c @@ -457,10 +457,12 @@ rts_shutdown(struct socket *so, enum shutdown_how how) */ switch (how) { case SHUT_RD: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); break; case SHUT_RDWR: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); /* FALLTHROUGH */ case SHUT_WR: socantsendmore(so); diff --git a/sys/netinet/raw_ip.c b/sys/netinet/raw_ip.c index a6bef1c7e27..004aaea01bf 100644 --- a/sys/netinet/raw_ip.c +++ b/sys/netinet/raw_ip.c @@ -994,10 +994,12 @@ rip_shutdown(struct socket *so, enum shutdown_how how) switch (how) { case SHUT_RD: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); break; case SHUT_RDWR: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); /* FALLTHROUGH */ case SHUT_WR: socantsendmore(so); diff --git a/sys/netinet/sctp_usrreq.c b/sys/netinet/sctp_usrreq.c index ec9f211b519..51c056e052a 100644 --- a/sys/netinet/sctp_usrreq.c +++ b/sys/netinet/sctp_usrreq.c @@ -868,11 +868,7 @@ sctp_shutdown(struct socket *so, enum shutdown_how how) SCTP_TCB_UNLOCK(stcb); } SCTP_INP_WUNLOCK(inp); - /* - * XXXGL: does SCTP need sorflush()? This is what old - * soshutdown() used to do for all kinds of sockets. - */ - sorflush(so); + socantrcvmore(so); if (how == SHUT_RD) break; /* FALLTHROUGH */ diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c index ccd6a6149da..7c8e3d7e72d 100644 --- a/sys/netinet/tcp_usrreq.c +++ b/sys/netinet/tcp_usrreq.c @@ -824,10 +824,12 @@ tcp_usr_shutdown(struct socket *so, enum shutdown_how how) switch (how) { case SHUT_RD: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); break; case SHUT_RDWR: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); /* FALLTHROUGH */ case SHUT_WR: /* diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c index f91a96edeb6..b68ec95a923 100644 --- a/sys/netinet/udp_usrreq.c +++ b/sys/netinet/udp_usrreq.c @@ -1696,10 +1696,12 @@ udp_shutdown(struct socket *so, enum shutdown_how how) switch (how) { case SHUT_RD: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); break; case SHUT_RDWR: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); /* FALLTHROUGH */ case SHUT_WR: socantsendmore(so); diff --git a/sys/netinet6/raw_ip6.c b/sys/netinet6/raw_ip6.c index 3264de33181..5b31a84f31e 100644 --- a/sys/netinet6/raw_ip6.c +++ b/sys/netinet6/raw_ip6.c @@ -839,10 +839,12 @@ rip6_shutdown(struct socket *so, enum shutdown_how how) switch (how) { case SHUT_RD: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); break; case SHUT_RDWR: - sorflush(so); + socantrcvmore(so); + sbrelease(so, SO_RCV); /* FALLTHROUGH */ case SHUT_WR: socantsendmore(so); diff --git a/sys/sys/socketvar.h b/sys/sys/socketvar.h index 19ca52177d1..5d651b36b1e 100644 --- a/sys/sys/socketvar.h +++ b/sys/sys/socketvar.h @@ -501,7 +501,6 @@ int soreceive_generic(struct socket *so, struct sockaddr **paddr, void sorele_locked(struct socket *so); void sodealloc(struct socket *); int soreserve(struct socket *so, u_long sndcc, u_long rcvcc); -void sorflush(struct socket *so); int sosend(struct socket *so, struct sockaddr *addr, struct uio *uio, struct mbuf *top, struct mbuf *control, int flags, struct thread *td);