[SSI] openssi/kernel/include/cluster/ssi/ipc unixnm.h,1.13,1.14

Update of /cvsroot/ssic-linux/openssi/kernel/include/cluster/ssi/ipc
In directory fdv4jf1.ch3.sourceforge.com:/tmp/cvs-serv16276/include/cluster/ssi/ipc

Modified Files:
      Tag: OPENSSI-FC
	unixnm.h 
Log Message:
IPC:
- Regression:
  - rmtunix_socket_info structure lookup race. (#ifdef RCU_RMTUNIX_CACHE)
  - missing sock_hold() for rmtunix_cache_info(). (#ifdef IPC_STALE_RMTUNIX_CACHE_FIX)

 cluster/ssi/cfs/cfs_ipcshm.c     |    4 -
 cluster/ssi/cfs/svrcfs.c         |   37 +++++----------
 cluster/ssi/ipc/rmtunix.c        |   14 +----
 cluster/ssi/vproc/vp_subr.c      |    5 --
 include/cluster/ssi/ipc/unixnm.h |   93 ++++++++++++++++++++++++---------------
 include/cluster/ssi/unix.h       |   34 ++------------
 include/linux/config.h           |    5 +-
 7 files changed, 83 insertions(+), 109 deletions(-)


Index: unixnm.h
===================================================================
RCS file: /cvsroot/ssic-linux/openssi/kernel/include/cluster/ssi/ipc/unixnm.h,v
retrieving revision 1.13
retrieving revision 1.14
diff -u -d -r1.13 -r1.14
--- unixnm.h	7 Feb 2009 04:31:42 -0000	1.13
+++ unixnm.h	8 Feb 2009 02:44:43 -0000	1.14
@@ -149,15 +149,23 @@
 {
 	struct rmtunix_socket_info *info =
 		(struct rmtunix_socket_info *)(unix_peer(s));
+
 	SSI_ASSERT(rmtunix_ismagic(unix_peer(s)));
+#ifdef IPC_STALE_RMTUNIX_CACHE_FIX
+	SSI_ASSERT(atomic_read(&info->rsk_refcnt));
+
+	if (!rmtunix_ismagic(s))
+		sock_hold(s); /* RT: for _rmtunix_dealloc() */
+	info->sk = s;
+	info->rsk_cached = 1;
+#endif
 
 	spin_lock(&rmtunix_cache_listlock);
 #ifdef DEBUG
 	++rmtunix_cache_size;
 #endif
+#ifndef IPC_STALE_RMTUNIX_CACHE_FIX
 	info->sk = s;
-#ifdef IPC_STALE_RMTUNIX_CACHE_FIX
-	info->rsk_cached = 1;
 #endif
 #ifdef RCU_RMTUNIX_CACHE
 	list_add_rcu(&info->list, &rmtunix_cache_list);
@@ -176,16 +184,13 @@
 	rcu_read_lock();
 	list_for_each_entry_rcu(info, &rmtunix_cache_list, list) {
 		if (info->sk == s) {
-#ifdef IPC_STALE_RMTUNIX_CACHE_FIX
 			LOCK_SPIN_LOCK(&info->rsk_spinlock);
 			if (!info->rsk_cached) {
 				UNLOCK_SPIN_LOCK(&info->rsk_spinlock);
 				break;
 			}
-			/* rmtunix_decache_info() is our only caller */
-			info->rsk_cached = 0;
+			atomic_inc(&info->rsk_refcnt);
 			UNLOCK_SPIN_LOCK(&info->rsk_spinlock);
-#endif
 			rcu_read_unlock();
 			return info;
 		}
@@ -206,33 +211,29 @@
 }
 
 static inline void
-rmtunix_decache_info(unix_socket *s)
+__rmtunix_decache_info(struct rmtunix_socket_info *info)
 {
-	struct rmtunix_socket_info *info =
-		(struct rmtunix_socket_info *)(unix_peer(s));
-	int orphan = 0;
-
-#ifndef RCU_RMTUNIX_CACHE
-	spin_lock(&rmtunix_cache_listlock);
-#endif
-	if (!info) {
-		orphan = 1;
-		info = rmtunix_cache_lookup(s);
-#ifdef IPC_STALE_RMTUNIX_CACHE_FIX
-		if (!info) return;
-#endif
-	}
-
-	SSI_ASSERT(info);
 	SSI_ASSERT( rmtunix_ismagic((struct sock *)info) );
 
 #ifdef RCU_RMTUNIX_CACHE
+	if (atomic_read(&info->rsk_refcnt) == 1)
+		might_sleep();
 	if (!atomic_dec_and_lock(&info->rsk_refcnt, &rmtunix_cache_listlock))
 		return;
-#ifdef IPC_STALE_RMTUNIX_CACHE_FIX
-	/* info->rsk_cached = 0; */ /* Done in rmtunix_cache_lookup() */
-#endif
+	LOCK_SPIN_LOCK(&info->rsk_spinlock);
+	if (atomic_read(&info->rsk_refcnt)) {
+		UNLOCK_SPIN_LOCK(&info->rsk_spinlock);
+		spin_unlock(&rmtunix_cache_listlock);
+		return;
+	}
+	info->rsk_cached = 0;
+	UNLOCK_SPIN_LOCK(&info->rsk_spinlock);
 	list_del_rcu(&info->list);
+#ifdef DEBUG
+	--rmtunix_cache_size;
+#endif
+	spin_unlock(&rmtunix_cache_listlock);
+	call_rcu(&info->rhead, rmtunix_dealloc);
 #else /* !RCU_RMTUNIX_CACHE */
 #ifdef IPC_STALE_RMTUNIX_CACHE_FIX
 	if (!atomic_dec_and_test(&info->rsk_refcnt)) {
@@ -240,27 +241,49 @@
 		return;
 	}
 	info->rsk_cached = 0;
-#else
-	info->sk = NULL;
 #endif
+	/* SSI_XXX: Missing sock_put(info->sk) ? */
+	info->sk = NULL;
 	list_del(&info->list);
-#endif /* !RCU_RMTUNIX_CACHE */
 #ifdef DEBUG
 	--rmtunix_cache_size;
 #endif
 	spin_unlock(&rmtunix_cache_listlock);
+#endif /* !RCU_RMTUNIX_CACHE */
+}
 
-	if (orphan) {
-#ifdef RCU_RMTUNIX_CACHE
-		call_rcu(&info->rhead, rmtunix_dealloc);
-#else
+static inline void
+rmtunix_decache_info(unix_socket *s)
+{
+	struct rmtunix_socket_info *info =
+			(struct rmtunix_socket_info *)(unix_peer(s));
+	int orphan = 0;
+
+#ifndef RCU_RMTUNIX_CACHE
+	spin_lock(&rmtunix_cache_listlock);
+#endif
+	if (!info) {
+		orphan = 1;
+		info = rmtunix_cache_lookup(s);
 #ifdef IPC_STALE_RMTUNIX_CACHE_FIX
-		info->sk = NULL;
+		if (!info)
+			return;
+		/* SSI_XXX: expect orphans? */
+		printk(KERN_DEBUG "%s: orphan rmtunix socket info found.\n",
+				__FUNCTION__);
+#else
+		SSI_ASSERT(info);
 #endif
+	}
+
+	(void) __rmtunix_decache_info(info);
+
+#ifndef RCU_RMTUNIX_CACHE
+	if (orphan) {
 		info->magic = 0;
 		kfree(info);
-#endif /* !RCU_RMTUNIX_CACHE */
 	}
+#endif
 }
 
 #ifndef IPC_STALE_RMTUNIX_CACHE_FIX


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