Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933084AbbLWG1x (ORCPT ); Wed, 23 Dec 2015 01:27:53 -0500 Received: from mail-lf0-f68.google.com ([209.85.215.68]:34212 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754177AbbLWG1w (ORCPT ); Wed, 23 Dec 2015 01:27:52 -0500 MIME-Version: 1.0 In-Reply-To: References: <20151209170813.GA12216@codebox> <20151221234443.GA11245@kroah.com> Date: Wed, 23 Dec 2015 11:57:50 +0530 Message-ID: Subject: Re: [PATCH] staging: lustre/lustre/libcfs: Fix type mismatch reported by sparse From: Niranjan Dighe To: "Dilger, Andreas" Cc: "Drokin, Oleg" , "Eremin, Dmitry" , James Simmons , Mike Rapoport , Patrick Boettcher , Matthew Tyler , "devel@driverdev.osuosl.org" , "linux-kernel@vger.kernel.org" , "lustre-devel@lists.lustre.org" , Greg Kroah-Hartman Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3187 Lines: 82 On Wed, Dec 23, 2015 at 3:34 AM, Dilger, Andreas wrote: > On 2015/12/22, 06:05, "Niranjan Dighe" wrote: > >>On Tue, Dec 22, 2015 at 5:14 AM, Greg Kroah-Hartman >> wrote: >>> On Wed, Dec 09, 2015 at 10:38:13PM +0530, Niranjan Dighe wrote: >>>> The third argument to function kportal_memhog_alloc is expected to >>>> be gfp_t whereas the actual argument was unsigned int. Fix this by >>>> explicitly typecasting to gfp_t >>>> >>>> Signed-off-by: Niranjan Dighe >>>> --- >>>> drivers/staging/lustre/lustre/libcfs/module.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/staging/lustre/lustre/libcfs/module.c >>>>b/drivers/staging/lustre/lustre/libcfs/module.c >>>> index 96d9d46..9c79f6e 100644 >>>> --- a/drivers/staging/lustre/lustre/libcfs/module.c >>>> +++ b/drivers/staging/lustre/lustre/libcfs/module.c >>>> @@ -268,7 +268,7 @@ static int libcfs_ioctl_int(struct cfs_psdev_file >>>>*pfile, unsigned long cmd, >>>> /* XXX The ioc_flags is not GFP flags now, need >>>>to be fixed */ >>>> err = kportal_memhog_alloc(pfile->private_data, >>>> data->ioc_count, >>>> - data->ioc_flags); >>>> + (__force gfp_t)data->ioc_flags); >>> >>> No, please fix the type to be correct properly, like the comment says >>> needs to be done. >>> >>> thanks, >>> >>> greg k-h >> >>Hello Greg, >> >>I could see that the ioc_flags member of the struct libcfs_ioctl_data >>is used as gfp_t only in the >>case of the ioctl IOC_LIBCFS_MEMHOG. I can think of following ways to >>correct it - >> >>1. Create a union that has 2 different types encapsulated, something like >>this - >> union { >> __u32 ioc_flags; >> gfp_t alloc_flags; >> }flags; >>Because, the ioc_flags seems to be used in different contexts at >>different places throughout the >>drivers/staging/lustre directory. >> >>2. Is it OK to hardcode the appropriate gfp_t flags for the >>IOC_LIBCFS_MEMHOG, as the userspace >>seems to be taking the decision about the page allocation >>zone/strategy, is this what is intended? > > The memhog functionality is used to introduce memory pressure on a client > or server during operation to test error handling as well as memory > allocation deadlocks (e.g. GFP_KERNEL used where GFP_NOFS should be used). > There are other ways to do this in the kernel today, so all of the memhog > code could just be deleted I think. > > This looks like kportal_memhog_alloc(), kportal_memhog_free(), > IOC_LIBCFS_MEMHOG, and struct libcfs_device_userstate could be removed. > > > Cheers, Andreas > Thanks Andreas, I will send out a separate patch with the cleanup as you suggested. Regards, Niranjan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/