orangefs: simplify compat ioctl handling

no need to mess with copy_in_user(), etc...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/orangefs/devorangefs-req.c

@@ -716,37 +716,6 @@ struct ORANGEFS_dev_map_desc32 {
 	__s32 count;
 };
 
-static unsigned long translate_dev_map26(unsigned long args, long *error)
-{
-	struct ORANGEFS_dev_map_desc32 __user *p32 = (void __user *)args;
-	/*
-	 * Depending on the architecture, allocate some space on the
-	 * user-call-stack based on our expected layout.
-	 */
-	struct ORANGEFS_dev_map_desc __user *p =
-	    compat_alloc_user_space(sizeof(*p));
-	compat_uptr_t addr;
-
-	*error = 0;
-	/* get the ptr from the 32 bit user-space */
-	if (get_user(addr, &p32->ptr))
-		goto err;
-	/* try to put that into a 64-bit layout */
-	if (put_user(compat_ptr(addr), &p->ptr))
-		goto err;
-	/* copy the remaining fields */
-	if (copy_in_user(&p->total_size, &p32->total_size, sizeof(__s32)))
-		goto err;
-	if (copy_in_user(&p->size, &p32->size, sizeof(__s32)))
-		goto err;
-	if (copy_in_user(&p->count, &p32->count, sizeof(__s32)))
-		goto err;
-	return (unsigned long)p;
-err:
-	*error = -EFAULT;
-	return 0;
-}
-
 /*
  * 32 bit user-space apps' ioctl handlers when kernel modules
  * is compiled as a 64 bit one
@@ -755,25 +724,26 @@ static long orangefs_devreq_compat_ioctl(struct file *filp, unsigned int cmd,
 				      unsigned long args)
 {
 	long ret;
-	unsigned long arg = args;
 
 	/* Check for properly constructed commands */
 	ret = check_ioctl_command(cmd);
 	if (ret < 0)
 		return ret;
 	if (cmd == ORANGEFS_DEV_MAP) {
-		/*
-		 * convert the arguments to what we expect internally
-		 * in kernel space
-		 */
-		arg = translate_dev_map26(args, &ret);
-		if (ret < 0) {
-			gossip_err("Could not translate dev map\n");
-			return ret;
-		}
+		struct ORANGEFS_dev_map_desc desc;
+		struct ORANGEFS_dev_map_desc32 d32;
+
+		if (copy_from_user(&d32, (void __user *)args, sizeof(d32)))
+			return -EFAULT;
+
+		desc.ptr = compat_ptr(d32.ptr);
+		desc.total_size = d32.total_size;
+		desc.size = d32.size;
+		desc.count = d32.count;
+		return orangefs_bufmap_initialize(&desc);
 	}
 	/* no other ioctl requires translation */
-	return dispatch_ioctl_command(cmd, arg);
+	return dispatch_ioctl_command(cmd, args);
 }
 
 #endif /* CONFIG_COMPAT is in .config */