[PATCH] s390: 31bit emulation.

Bug fixes for the 31 bit emulation layer. New interface
[un]register_ioctl32_conversion.

arch/s390x/kernel/ioctl32.c

@@ -1024,6 +1024,8 @@ int sys32_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
 static void ioctl32_insert(struct ioctl32_list *entry)
 {
 	int hash = ioctl32_hash(entry->handler.cmd);
+
+	entry->next = 0;
 	if (!ioctl32_hash_table[hash])
 		ioctl32_hash_table[hash] = entry;
 	else {
@@ -1032,10 +1034,51 @@ static void ioctl32_insert(struct ioctl32_list *entry)
 		while (l->next)
 			l = l->next;
 		l->next = entry;
-		entry->next = 0;
 	}
 }
 
+int register_ioctl32_conversion(unsigned int cmd,
+				int (*handler)(unsigned int, unsigned int,
+					       unsigned long, struct file *))
+{
+	struct ioctl32_list *l, *new;
+	int hash;
+
+	hash = ioctl32_hash(cmd);
+	for (l = ioctl32_hash_table[hash]; l != NULL; l = l->next)
+		if (l->handler.cmd == cmd)
+			return -EBUSY;
+	new = kmalloc(sizeof(struct ioctl32_list), GFP_KERNEL);
+	if (new == NULL)
+		return -ENOMEM;
+	new->handler.cmd = cmd;
+	new->handler.function = (void *) handler;
+	ioctl32_insert(new);
+	return 0;
+}
+
+int unregister_ioctl32_conversion(unsigned int cmd)
+{
+	struct ioctl32_list *p, *l;
+	int hash;
+
+	hash = ioctl32_hash(cmd);
+	p = NULL;
+	for (l = ioctl32_hash_table[hash]; l != NULL; l = l->next) {
+		if (l->handler.cmd == cmd)
+			break;
+		p = l;
+	}
+	if (l == NULL)
+		return -ENOENT;
+	if (p == NULL)
+		ioctl32_hash_table[hash] = l->next;
+	else
+		p->next = l->next;
+	kfree(l);
+	return 0;
+}
+
 static int __init init_ioctl32(void)
 {
 	int i;

arch/s390x/kernel/s390_ksyms.c

@@ -60,6 +60,20 @@ EXPORT_SYMBOL(dump_fpu);
 EXPORT_SYMBOL(overflowuid);
 EXPORT_SYMBOL(overflowgid);
 
+#ifdef CONFIG_S390_SUPPORT
+/*
+ * Dynamically add/remove 31 bit ioctl conversion functions.
+ */
+extern int register_ioctl32_conversion(unsigned int cmd,
+				       int (*handler)(unsigned int, 
+						      unsigned int,
+						      unsigned long,
+						      struct file *));
+int unregister_ioctl32_conversion(unsigned int cmd);
+EXPORT_SYMBOL(register_ioctl32_conversion);
+EXPORT_SYMBOL(unregister_ioctl32_conversion);
+#endif
+
 /*
  * misc.
  */

arch/s390x/kernel/wrapper32.S

@@ -17,14 +17,14 @@ sys32_read_wrapper:
 	llgfr	%r2,%r2			# unsigned int
 	llgtr	%r3,%r3			# char *
 	llgfr	%r4,%r4			# size_t
-	jg	sys_read		# branch to sys_read
+	jg	sys32_read		# branch to sys_read
 
 	.globl  sys32_write_wrapper 
 sys32_write_wrapper:
 	llgfr	%r2,%r2			# unsigned int
 	llgtr	%r3,%r3			# const char *
 	llgfr	%r4,%r4			# size_t
-	jg	sys_write		# branch to system call
+	jg	sys32_write		# branch to system call
 
 	.globl  sys32_open_wrapper 
 sys32_open_wrapper: