The branch main has been updated by glebius:
URL:
https://cgit.FreeBSD.org/src/commit/?id=ce69e37369aa44a96113387253aadc5e49246928
commit ce69e37369aa44a96113387253aadc5e49246928
Author: Gleb Smirnoff <gleb...@freebsd.org>
AuthorDate: 2024-02-03 21:08:41 +0000
Commit: Gleb Smirnoff <gleb...@freebsd.org>
CommitDate: 2024-02-03 21:08:41 +0000
Revert "sockets: retire sorflush()"
Provide a comment in sorflush() why the socket I/O sx(9) lock is actually
important.
This reverts commit 507f87a799cf0811ce30f0ae7f10ba19b2fd3db3.
---
sys/kern/uipc_socket.c | 42 +++++++++++++++++++++++++++++++++++++++---
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, 55 insertions(+), 24 deletions(-)
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 5e5e7d2cd058..b647766cf258 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(),
- * which are usually called from a pre-set VNET context. sopoll() currently
- * does not need a VNET context to be set.
+ * sofree(), sorele(), sonewconn() and sorflush(), which are usually called
+ * from a pre-set VNET context. sopoll() currently does not need a VNET
+ * context to be set.
*/
#include <sys/cdefs.h>
@@ -2964,6 +2964,42 @@ 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.
+ *
+ * The SOCK_IO_RECV_LOCK() is important here as there some pr_soreceive
+ * methods that read the top of the socket buffer without acquisition
+ * of the socket buffer mutex, assuming that top of the buffer
+ * exclusively belongs to the read(2) syscall. This is handy when
+ * performing MSG_PEEK.
+ */
+ 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 e4183232700e..e0411ed0c1d0 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -457,12 +457,10 @@ rts_shutdown(struct socket *so, enum shutdown_how how)
*/
switch (how) {
case SHUT_RD:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
break;
case SHUT_RDWR:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
/* FALLTHROUGH */
case SHUT_WR:
socantsendmore(so);
diff --git a/sys/netinet/raw_ip.c b/sys/netinet/raw_ip.c
index 004aaea01bfa..a6bef1c7e275 100644
--- a/sys/netinet/raw_ip.c
+++ b/sys/netinet/raw_ip.c
@@ -994,12 +994,10 @@ rip_shutdown(struct socket *so, enum shutdown_how how)
switch (how) {
case SHUT_RD:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
break;
case SHUT_RDWR:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
/* FALLTHROUGH */
case SHUT_WR:
socantsendmore(so);
diff --git a/sys/netinet/sctp_usrreq.c b/sys/netinet/sctp_usrreq.c
index b847271a7bd3..70fe021be766 100644
--- a/sys/netinet/sctp_usrreq.c
+++ b/sys/netinet/sctp_usrreq.c
@@ -868,7 +868,11 @@ sctp_shutdown(struct socket *so, enum shutdown_how how)
SCTP_TCB_UNLOCK(stcb);
}
SCTP_INP_WUNLOCK(inp);
- socantrcvmore(so);
+ /*
+ * XXXGL: does SCTP need sorflush()? This is what old
+ * soshutdown() used to do for all kinds of sockets.
+ */
+ sorflush(so);
if (how == SHUT_RD)
break;
/* FALLTHROUGH */
diff --git a/sys/netinet/tcp_usrreq.c b/sys/netinet/tcp_usrreq.c
index 7c8e3d7e72db..ccd6a6149dae 100644
--- a/sys/netinet/tcp_usrreq.c
+++ b/sys/netinet/tcp_usrreq.c
@@ -824,12 +824,10 @@ tcp_usr_shutdown(struct socket *so, enum shutdown_how how)
switch (how) {
case SHUT_RD:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
break;
case SHUT_RDWR:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
/* FALLTHROUGH */
case SHUT_WR:
/*
diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c
index 24bc3403b0f7..9dad79e95b04 100644
--- a/sys/netinet/udp_usrreq.c
+++ b/sys/netinet/udp_usrreq.c
@@ -1722,12 +1722,10 @@ udp_shutdown(struct socket *so, enum shutdown_how how)
switch (how) {
case SHUT_RD:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
break;
case SHUT_RDWR:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
/* FALLTHROUGH */
case SHUT_WR:
socantsendmore(so);
diff --git a/sys/netinet6/raw_ip6.c b/sys/netinet6/raw_ip6.c
index 5b31a84f31eb..3264de331817 100644
--- a/sys/netinet6/raw_ip6.c
+++ b/sys/netinet6/raw_ip6.c
@@ -839,12 +839,10 @@ rip6_shutdown(struct socket *so, enum shutdown_how how)
switch (how) {
case SHUT_RD:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
break;
case SHUT_RDWR:
- socantrcvmore(so);
- sbrelease(so, SO_RCV);
+ sorflush(so);
/* FALLTHROUGH */
case SHUT_WR:
socantsendmore(so);
diff --git a/sys/sys/socketvar.h b/sys/sys/socketvar.h
index 030087cbc17c..cba7dd655aa0 100644
--- a/sys/sys/socketvar.h
+++ b/sys/sys/socketvar.h
@@ -501,6 +501,7 @@ 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);
