From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751762Ab1IWTCz (ORCPT ); Fri, 23 Sep 2011 15:02:55 -0400 Received: from mail127.messagelabs.com ([216.82.250.115]:7799 "EHLO mail127.messagelabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751402Ab1IWTCx (ORCPT ); Fri, 23 Sep 2011 15:02:53 -0400 X-Env-Sender: hartleys@visionengravers.com X-Msg-Ref: server-11.tower-127.messagelabs.com!1316804302!28782095!341 X-Originating-IP: [216.166.12.180] X-StarScan-Version: 6.3.6; banners=-,-,- X-VirusChecked: Checked From: H Hartley Sweeten To: Joe Perches CC: Linux Kernel , "linux-btrfs@vger.kernel.org" , "chris.mason@oracle.com" Date: Fri, 23 Sep 2011 14:02:27 -0500 Subject: RE: [PATCH] btrfs/ioctl.c: quiet sparse warnings Thread-Topic: [PATCH] btrfs/ioctl.c: quiet sparse warnings Thread-Index: Acx6HNqGsHcPnI3zQW2xoY3849N/rAABUvMg Message-ID: References: <201109231107.54227.hartleys@visionengravers.com> <1316801760.28330.5.camel@Joe-Laptop> In-Reply-To: <1316801760.28330.5.camel@Joe-Laptop> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id p8NJ32LI006410 On Friday, September 23, 2011 11:16 AM, Joe Perches wrote: > On Fri, 2011-09-23 at 11:07 -0700, H Hartley Sweeten wrote: >> Quiet the following sparse warnings: > [] >> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > [] >> @@ -2705,7 +2705,7 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) >> up_read(&info->groups_sem); >> } >> >> - user_dest = (struct btrfs_ioctl_space_info *) >> + user_dest = (struct btrfs_ioctl_space_info __user *) >> (arg + sizeof(struct btrfs_ioctl_space_args)); > > user_dest = arg; > user_dest++; > > ? That produces a new sparse warning: fs/btrfs/ioctl.c: In function ‘btrfs_ioctl_space_info’: fs/btrfs/ioctl.c:2708: warning: ‘user_dest’ may be used uninitialized in this function I guess user_dest could be set at the start of the function. This would also remove the cast of arg in the first copy_from_user. Something like this: ------ diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 970977a..9e7e5dc 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2599,13 +2599,13 @@ static void get_block_group_info(struct list_head *groups_list, } } -long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) +static long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) { struct btrfs_ioctl_space_args space_args; struct btrfs_ioctl_space_info space; struct btrfs_ioctl_space_info *dest; struct btrfs_ioctl_space_info *dest_orig; - struct btrfs_ioctl_space_info __user *user_dest; + struct btrfs_ioctl_space_info __user *user_dest = arg; struct btrfs_space_info *info; u64 types[] = {BTRFS_BLOCK_GROUP_DATA, BTRFS_BLOCK_GROUP_SYSTEM, @@ -2617,9 +2617,7 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) u64 slot_count = 0; int i, c; - if (copy_from_user(&space_args, - (struct btrfs_ioctl_space_args __user *)arg, - sizeof(space_args))) + if (copy_from_user(&space_args, user_dest, sizeof(space_args))) return -EFAULT; for (i = 0; i < num_types; i++) { @@ -2705,8 +2703,7 @@ long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg) up_read(&info->groups_sem); } - user_dest = (struct btrfs_ioctl_space_info *) - (arg + sizeof(struct btrfs_ioctl_space_args)); + user_dest++; if (copy_to_user(user_dest, dest_orig, alloc_size)) ret = -EFAULT; {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I