git: bc7605647c71 - main - sockets: use positive flag for file descriptor socket reference
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Date: Mon, 04 Jul 2022 19:41:16 UTC
The branch main has been updated by glebius:
URL: https://cgit.FreeBSD.org/src/commit/?id=bc7605647c7193af7eba4b4af65dc7b66a118a09
commit bc7605647c7193af7eba4b4af65dc7b66a118a09
Author: Gleb Smirnoff <glebius@FreeBSD.org>
AuthorDate: 2022-07-04 19:40:51 +0000
Commit: Gleb Smirnoff <glebius@FreeBSD.org>
CommitDate: 2022-07-04 19:40:51 +0000
sockets: use positive flag for file descriptor socket reference
Rename SS_NOFDREF to SS_FDREF and flip all bitwise operations.
Mark sockets created by socreate() with SS_FDREF.
This change is mostly illustrative. With it we see that SS_FDREF
is a debugging flag, since:
* socreate() takes a reference with soref().
* on accept path solisten_dequeue() takes a reference
with soref() and then soaccept() sets SS_FDREF.
* soclose() checks SS_FDREF, removes it and does sorele().
Reviewed by: tuexen
Differential revision: https://reviews.freebsd.org/D35678
---
sys/kern/uipc_debug.c | 4 ++--
sys/kern/uipc_socket.c | 31 +++++++++++++++++--------------
sys/sys/socketvar.h | 2 +-
3 files changed, 20 insertions(+), 17 deletions(-)
diff --git a/sys/kern/uipc_debug.c b/sys/kern/uipc_debug.c
index cbc26489d8fa..dee2b12e7cb7 100644
--- a/sys/kern/uipc_debug.c
+++ b/sys/kern/uipc_debug.c
@@ -158,8 +158,8 @@ db_print_sostate(short so_state)
int comma;
comma = 0;
- if (so_state & SS_NOFDREF) {
- db_printf("%sSS_NOFDREF", comma ? ", " : "");
+ if (so_state & SS_FDREF) {
+ db_printf("%sSS_FDREF", comma ? ", " : "");
comma = 1;
}
if (so_state & SS_ISCONNECTED) {
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 5063ae5a56e0..aa0470a51a5f 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -498,8 +498,8 @@ sodealloc(struct socket *so)
}
/*
- * socreate returns a socket with a ref count of 1. The socket should be
- * closed with soclose().
+ * socreate returns a socket with a ref count of 1 and a file descriptor
+ * reference. The socket should be closed with soclose().
*/
int
socreate(int dom, struct socket **aso, int type, int proto,
@@ -540,6 +540,7 @@ socreate(int dom, struct socket **aso, int type, int proto,
return (ENOBUFS);
so->so_type = type;
+ so->so_state = SS_FDREF;
so->so_cred = crhold(cred);
if ((prp->pr_domain->dom_family == PF_INET) ||
(prp->pr_domain->dom_family == PF_INET6) ||
@@ -740,7 +741,7 @@ sonewconn(struct socket *head, int connstatus)
so->so_type = head->so_type;
so->so_options = head->so_options & ~SO_ACCEPTCONN;
so->so_linger = head->so_linger;
- so->so_state = head->so_state | SS_NOFDREF;
+ so->so_state = head->so_state & ~SS_FDREF;
so->so_fibnum = head->so_fibnum;
so->so_proto = head->so_proto;
so->so_cred = crhold(head->so_cred);
@@ -1126,7 +1127,7 @@ solisten_dequeue(struct socket *head, struct socket **ret, int flags)
* - There are no outstanding file descriptor references or related consumers
* (so_count == 0).
*
- * - The socket has been closed by user space, if ever open (SS_NOFDREF).
+ * - The socket has been closed by user space, if ever open (no SS_FDREF).
*
* - The protocol does not have an outstanding strong reference on the socket
* (SS_PROTOREF).
@@ -1143,7 +1144,7 @@ sofree(struct socket *so)
SOCK_LOCK_ASSERT(so);
- if ((so->so_state & (SS_NOFDREF | SS_PROTOREF)) != SS_NOFDREF ||
+ if ((so->so_state & (SS_FDREF | SS_PROTOREF)) != 0 ||
refcount_load(&so->so_count) != 0 || so->so_qstate == SQ_COMP) {
SOCK_UNLOCK(so);
return;
@@ -1159,7 +1160,7 @@ sofree(struct socket *so)
* To solve race between close of a listening socket and
* a socket on its incomplete queue, we need to lock both.
* The order is first listening socket, then regular.
- * Since we don't have SS_NOFDREF neither SS_PROTOREF, this
+ * Since we don't have SS_FDREF neither SS_PROTOREF, this
* function and the listening socket are the only pointers
* to so. To preserve so and sol, we reference both and then
* relock.
@@ -1254,7 +1255,8 @@ soclose(struct socket *so)
int error = 0;
bool listening, last __diagused;
- KASSERT(!(so->so_state & SS_NOFDREF), ("soclose: SS_NOFDREF on enter"));
+ KASSERT(so->so_state & SS_FDREF,
+ ("%s: %p no SS_FDREF on enter", __func__, so));
CURVNET_SET(so->so_vnet);
funsetown(&so->so_sigio);
@@ -1306,8 +1308,9 @@ drop:
__func__, so));
}
}
- KASSERT((so->so_state & SS_NOFDREF) == 0, ("soclose: NOFDREF"));
- so->so_state |= SS_NOFDREF;
+ KASSERT(so->so_state & SS_FDREF,
+ ("%s: %p no SS_FDREF upon lock", __func__, so));
+ so->so_state &= ~SS_FDREF;
sorele_locked(so);
if (listening) {
struct socket *sp, *tsp;
@@ -1352,9 +1355,8 @@ soabort(struct socket *so)
* current thread is responsible for arranging for no references, but
* is as close as we can get for now.
*/
- KASSERT(so->so_count == 0, ("soabort: so_count"));
- KASSERT((so->so_state & SS_PROTOREF) == 0, ("soabort: SS_PROTOREF"));
- KASSERT(so->so_state & SS_NOFDREF, ("soabort: !SS_NOFDREF"));
+ KASSERT((so->so_state & (SS_FDREF | SS_PROTOREF)) == 0 &&
+ so->so_count == 0, ("%s: so %p has references", __func__, so));
VNET_SO_ASSERT(so);
if (so->so_proto->pr_usrreqs->pru_abort != NULL)
@@ -1369,8 +1371,9 @@ soaccept(struct socket *so, struct sockaddr **nam)
int error;
SOCK_LOCK(so);
- KASSERT((so->so_state & SS_NOFDREF) != 0, ("soaccept: !NOFDREF"));
- so->so_state &= ~SS_NOFDREF;
+ KASSERT((so->so_state & SS_FDREF) == 0,
+ ("%s: %p has SS_FDREF", __func__, so));
+ so->so_state |= SS_FDREF;
SOCK_UNLOCK(so);
CURVNET_SET(so->so_vnet);
diff --git a/sys/sys/socketvar.h b/sys/sys/socketvar.h
index 85aa7cbfea0f..d1ce687ac956 100644
--- a/sys/sys/socketvar.h
+++ b/sys/sys/socketvar.h
@@ -210,7 +210,7 @@ struct socket {
* Many fields will be read without locks to improve performance and avoid
* lock order issues. However, this approach must be used with caution.
*/
-#define SS_NOFDREF 0x0001 /* no file table ref any more */
+#define SS_FDREF 0x0001 /* strong file descriptor reference */
#define SS_ISCONNECTED 0x0002 /* socket connected to a peer */
#define SS_ISCONNECTING 0x0004 /* in process of connecting to peer */
#define SS_ISDISCONNECTING 0x0008 /* in process of disconnecting */