Binary files linux-2.5.43/arch/i386/boot/compressed/vmlinux.bin.gz and linux-2.5.43-ipc/arch/i386/boot/compressed/vmlinux.bin.gz differ
diff -urN -X dontdiff linux-2.5.43/include/linux/ipc.h linux-2.5.43-ipc/include/linux/ipc.h
--- linux-2.5.43/include/linux/ipc.h	Tue Oct 15 20:26:43 2002
+++ linux-2.5.43-ipc/include/linux/ipc.h	Wed Oct 16 09:48:28 2002
@@ -56,6 +56,7 @@
 /* used by in-kernel data structures */
 struct kern_ipc_perm
 {
+	spinlock_t	lock;
 	key_t		key;
 	uid_t		uid;
 	gid_t		gid;
diff -urN -X dontdiff linux-2.5.43/ipc/shm.c linux-2.5.43-ipc/ipc/shm.c
--- linux-2.5.43/ipc/shm.c	Tue Oct 15 20:28:22 2002
+++ linux-2.5.43-ipc/ipc/shm.c	Wed Oct 16 09:48:28 2002
@@ -38,8 +38,6 @@
 
 #define shm_lock(id)	((struct shmid_kernel*)ipc_lock(&shm_ids,id))
 #define shm_unlock(id)	ipc_unlock(&shm_ids,id)
-#define shm_lockall()	ipc_lockall(&shm_ids)
-#define shm_unlockall()	ipc_unlockall(&shm_ids)
 #define shm_get(id)	((struct shmid_kernel*)ipc_get(&shm_ids,id))
 #define shm_buildid(id, seq) \
 	ipc_buildid(&shm_ids, id, seq)
@@ -409,14 +407,12 @@
 
 		memset(&shm_info,0,sizeof(shm_info));
 		down(&shm_ids.sem);
-		shm_lockall();
 		shm_info.used_ids = shm_ids.in_use;
 		shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
 		shm_info.shm_tot = shm_tot;
 		shm_info.swap_attempts = 0;
 		shm_info.swap_successes = 0;
 		err = shm_ids.max_id;
-		shm_unlockall();
 		up(&shm_ids.sem);
 		if(copy_to_user (buf, &shm_info, sizeof(shm_info)))
 			return -EFAULT;
diff -urN -X dontdiff linux-2.5.43/ipc/util.c linux-2.5.43-ipc/ipc/util.c
--- linux-2.5.43/ipc/util.c	Tue Oct 15 20:27:54 2002
+++ linux-2.5.43-ipc/ipc/util.c	Wed Oct 16 09:48:28 2002
@@ -92,8 +92,10 @@
 {
 	int id;
 	struct kern_ipc_perm* p;
+	int max_id = ids->max_id;
 
-	for (id = 0; id <= ids->max_id; id++) {
+	read_barrier_depends();
+	for (id = 0; id <= max_id; id++) {
 		p = ids->entries[id].p;
 		if(p==NULL)
 			continue;
@@ -106,8 +108,8 @@
 static int grow_ary(struct ipc_ids* ids, int newsize)
 {
 	struct ipc_id* new;
-	struct ipc_id* old;
 	int i;
+	struct rcu_ipc_array *arg = NULL;
 
 	if(newsize > IPCMNI)
 		newsize = IPCMNI;
@@ -121,14 +123,19 @@
 	for(i=ids->size;i<newsize;i++) {
 		new[i].p = NULL;
 	}
+	arg = (struct rcu_ipc_array *) kmalloc(sizeof(*arg), GFP_KERNEL);
+	if(arg == NULL)
+		return ids->size;
+	arg->entries = ids->entries;
+	arg->size = ids->size;
+	
 	spin_lock(&ids->ary);
-
-	old = ids->entries;
 	ids->entries = new;
-	i = ids->size;
+	wmb();
 	ids->size = newsize;
 	spin_unlock(&ids->ary);
-	ipc_free(old, sizeof(struct ipc_id)*i);
+
+	call_rcu(&arg->rh, ipc_free_callback, arg);
 	return ids->size;
 }
 
@@ -166,7 +173,9 @@
 	if(ids->seq > ids->seq_max)
 		ids->seq = 0;
 
-	spin_lock(&ids->ary);
+	new->lock = SPIN_LOCK_UNLOCKED;
+	rcu_read_lock();
+	spin_lock(&new->lock);
 	ids->entries[id].p = new;
 	return id;
 }
@@ -188,6 +197,7 @@
 	int lid = id % SEQ_MULTIPLIER;
 	if(lid >= ids->size)
 		BUG();
+	rmb();
 	p = ids->entries[lid].p;
 	ids->entries[lid].p = NULL;
 	if(p==NULL)
@@ -239,7 +249,12 @@
 	else
 		kfree(ptr);
 }
-
+static void ipc_free_callback(void * arg)
+{
+	struct rcu_ipc_array *a = (struct rcu_ipc_array *)arg;
+	ipc_free(a->entries, a->size);
+	kfree(arg);
+}
 /**
  *	ipcperms	-	check IPC permissions
  *	@ipcp: IPC permission set
diff -urN -X dontdiff linux-2.5.43/ipc/util.h linux-2.5.43-ipc/ipc/util.h
--- linux-2.5.43/ipc/util.h	Tue Oct 15 20:28:24 2002
+++ linux-2.5.43-ipc/ipc/util.h	Wed Oct 16 09:48:28 2002
@@ -4,6 +4,7 @@
  *
  * ipc helper functions (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
  */
+#include <linux/rcupdate.h>
 
 #define USHRT_MAX 0xffff
 #define SEQ_MULTIPLIER	(IPCMNI)
@@ -12,6 +13,12 @@
 void msg_init (void);
 void shm_init (void);
 
+struct rcu_ipc_array {
+	struct rcu_head rh;
+	struct ipc_id* entries;
+	int size;
+};
+
 struct ipc_ids {
 	int size;
 	int in_use;
@@ -44,11 +51,7 @@
  */
 void* ipc_alloc(int size);
 void ipc_free(void* ptr, int size);
-
-extern inline void ipc_lockall(struct ipc_ids* ids)
-{
-	spin_lock(&ids->ary);
-}
+void ipc_free_callback(void* arg);
 
 extern inline struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id)
 {
@@ -56,32 +59,43 @@
 	int lid = id % SEQ_MULTIPLIER;
 	if(lid >= ids->size)
 		return NULL;
-
+	rmb();
 	out = ids->entries[lid].p;
 	return out;
 }
 
-extern inline void ipc_unlockall(struct ipc_ids* ids)
-{
-	spin_unlock(&ids->ary);
-}
 extern inline struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
 {
 	struct kern_ipc_perm* out;
 	int lid = id % SEQ_MULTIPLIER;
-	if(lid >= ids->size)
-		return NULL;
 
-	spin_lock(&ids->ary);
+	rcu_read_lock();
+	if(lid >= ids->size) {
+		rcu_read_unlock();
+		return NULL;
+	}
+	rmb();
 	out = ids->entries[lid].p;
-	if(out==NULL)
-		spin_unlock(&ids->ary);
+	if(out==NULL) {
+		rcu_read_unlock();
+		return NULL;
+	}
+	spin_lock(&out->lock);
 	return out;
 }
 
 extern inline void ipc_unlock(struct ipc_ids* ids, int id)
 {
-	spin_unlock(&ids->ary);
+	int lid = id % SEQ_MULTIPLIER;
+	struct kern_ipc_perm* out;
+
+        if(lid >= ids->size)
+		return;
+	rmb();	
+	out = ids->entries[lid].p;
+	if (out)
+		spin_unlock(&out->lock);
+	rcu_read_unlock();
 }
 
 extern inline int ipc_buildid(struct ipc_ids* ids, int id, int seq)