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Message-ID: <c63c2212-16d0-4d4b-9055-afc1196d7da1@amd.com>
Date: Fri, 31 May 2024 14:02:37 +0530
User-Agent: Mozilla Thunderbird
Subject: Re: drivers/iommu/amd/iommu.c:2011 init_gcr3_table() warn: missing
 error code? 'ret'
To: Dan Carpenter <dan.carpenter@linaro.org>, oe-kbuild@lists.linux.dev
Cc: lkp@intel.com, oe-kbuild-all@lists.linux.dev,
 linux-kernel@vger.kernel.org, Joerg Roedel <jroedel@suse.de>,
 Jason Gunthorpe <jgg@nvidia.com>
References: <7765e9c3-414d-444a-8943-7e244c945e57@moroto.mountain>
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From: Vasant Hegde <vasant.hegde@amd.com>
In-Reply-To: <7765e9c3-414d-444a-8943-7e244c945e57@moroto.mountain>
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Hi Dan,


On 5/23/2024 8:39 PM, Dan Carpenter wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   29c73fc794c83505066ee6db893b2a83ac5fac63
> commit: c9e8701132e6cc162d082e7dad8a2e9110f5f8fd iommu/amd: Setup GCR3 table in advance if domain is SVA capable
> config: x86_64-randconfig-161-20240522 (https://download.01.org/0day-ci/archive/20240522/202405221116.X7cP3GzG-lkp@intel.com/config)
> compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> | Closes: https://lore.kernel.org/r/202405221116.X7cP3GzG-lkp@intel.com/
> 
> smatch warnings:
> drivers/iommu/amd/iommu.c:2011 init_gcr3_table() warn: missing error code? 'ret'
> 
> vim +/ret +2011 drivers/iommu/amd/iommu.c
> 
> c9e8701132e6cc Vasant Hegde 2024-04-18  1986  static int init_gcr3_table(struct iommu_dev_data *dev_data,
> c9e8701132e6cc Vasant Hegde 2024-04-18  1987  			   struct protection_domain *pdom)
> c9e8701132e6cc Vasant Hegde 2024-04-18  1988  {
> c9e8701132e6cc Vasant Hegde 2024-04-18  1989  	struct amd_iommu *iommu = get_amd_iommu_from_dev_data(dev_data);
> c9e8701132e6cc Vasant Hegde 2024-04-18  1990  	int max_pasids = dev_data->max_pasids;
> c9e8701132e6cc Vasant Hegde 2024-04-18  1991  	int ret = 0;
> c9e8701132e6cc Vasant Hegde 2024-04-18  1992  
> c9e8701132e6cc Vasant Hegde 2024-04-18  1993  	 /*
> c9e8701132e6cc Vasant Hegde 2024-04-18  1994  	  * If domain is in pt mode then setup GCR3 table only if device
> c9e8701132e6cc Vasant Hegde 2024-04-18  1995  	  * is PASID capable
> c9e8701132e6cc Vasant Hegde 2024-04-18  1996  	  */
> c9e8701132e6cc Vasant Hegde 2024-04-18  1997  	if (pdom_is_in_pt_mode(pdom) && !pdev_pasid_supported(dev_data))
> c9e8701132e6cc Vasant Hegde 2024-04-18  1998  		return ret;
> c9e8701132e6cc Vasant Hegde 2024-04-18  1999  
> c9e8701132e6cc Vasant Hegde 2024-04-18  2000  	/*
> c9e8701132e6cc Vasant Hegde 2024-04-18  2001  	 * By default, setup GCR3 table to support MAX PASIDs
> c9e8701132e6cc Vasant Hegde 2024-04-18  2002  	 * supported by the device/IOMMU.
> c9e8701132e6cc Vasant Hegde 2024-04-18  2003  	 */
> c9e8701132e6cc Vasant Hegde 2024-04-18  2004  	ret = setup_gcr3_table(&dev_data->gcr3_info, iommu,
> c9e8701132e6cc Vasant Hegde 2024-04-18  2005  			       max_pasids > 0 ?  max_pasids : 1);
> c9e8701132e6cc Vasant Hegde 2024-04-18  2006  	if (ret)
> c9e8701132e6cc Vasant Hegde 2024-04-18  2007  		return ret;
> c9e8701132e6cc Vasant Hegde 2024-04-18  2008  
> c9e8701132e6cc Vasant Hegde 2024-04-18  2009  	/* Setup GCR3[0] only if domain is setup with v2 page table mode */
> c9e8701132e6cc Vasant Hegde 2024-04-18  2010  	if (!pdom_is_v2_pgtbl_mode(pdom))
> c9e8701132e6cc Vasant Hegde 2024-04-18 @2011  		return ret;
> 
> From the comment, this looks like a false positive, but could you please
> change it to "return 0;"

ret is already zero. Hence I used 'ret'. Yeah . I can change this to zero.

-Vasant