[yiliu1765-iommufd:wip/iommufd_pasid 67/73] drivers/iommu/iommufd/pasid.c:29:1-3: WARNING: possible condition with no effect (if == else)

[yiliu1765-iommufd:wip/iommufd_pasid 67/73] drivers/iommu/iommufd/pasid.c:29:1-3: WARNING: possible condition with no effect (if == else)

[kernel test robot]

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: Yi Liu <yi.l.liu@intel.com>
TO: Kevin Tian <kevin.tian@intel.com>

tree:   https://github.com/yiliu1765/iommufd.git wip/iommufd_pasid
head:   e3941047a07be80cb3b87129cb372c1e6e7f4ced
commit: 0fb50342800a867a8e56866fddd1f3d0752c45a9 [67/73] iommufd: Allow attach/replace hwpt per pasid
:::::: branch date: 14 hours ago
:::::: commit date: 19 hours ago
config: arc-randconfig-r061-20230713 (https://download.01.org/0day-ci/archive/20230714/202307141101.6mFGzFS2-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230714/202307141101.6mFGzFS2-lkp@intel.com/reproduce)

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: Julia Lawall <julia.lawall@inria.fr>
| Closes: https://lore.kernel.org/r/202307141101.6mFGzFS2-lkp@intel.com/

cocci warnings: (new ones prefixed by >>)
>> drivers/iommu/iommufd/pasid.c:29:1-3: WARNING: possible condition with no effect (if == else)

vim +29 drivers/iommu/iommufd/pasid.c

0fb50342800a86 Kevin Tian 2023-05-22   9  
0fb50342800a86 Kevin Tian 2023-05-22  10  static int __iommufd_device_pasid_do_attach(struct iommufd_device *idev,
0fb50342800a86 Kevin Tian 2023-05-22  11  					    u32 pasid,
0fb50342800a86 Kevin Tian 2023-05-22  12  					    struct iommufd_hw_pagetable *hwpt,
0fb50342800a86 Kevin Tian 2023-05-22  13  					    bool replace)
0fb50342800a86 Kevin Tian 2023-05-22  14  {
0fb50342800a86 Kevin Tian 2023-05-22  15  	int rc;
0fb50342800a86 Kevin Tian 2023-05-22  16  
0fb50342800a86 Kevin Tian 2023-05-22  17  	/*
0fb50342800a86 Kevin Tian 2023-05-22  18  	 * Try to upgrade the domain we have. This is also required for
0fb50342800a86 Kevin Tian 2023-05-22  19  	 * pasid attach since pasid only matters for identifying a hwpt
0fb50342800a86 Kevin Tian 2023-05-22  20  	 * while cache coherency is about memory access semantics post
0fb50342800a86 Kevin Tian 2023-05-22  21  	 * walking hwpt.
0fb50342800a86 Kevin Tian 2023-05-22  22  	 */
0fb50342800a86 Kevin Tian 2023-05-22  23  	if (idev->enforce_cache_coherency) {
0fb50342800a86 Kevin Tian 2023-05-22  24  		rc = iommufd_hw_pagetable_enforce_cc(hwpt);
0fb50342800a86 Kevin Tian 2023-05-22  25  		if (rc)
0fb50342800a86 Kevin Tian 2023-05-22  26  			return rc;
0fb50342800a86 Kevin Tian 2023-05-22  27  	}
0fb50342800a86 Kevin Tian 2023-05-22  28  
0fb50342800a86 Kevin Tian 2023-05-22 @29  	if (!replace)
0fb50342800a86 Kevin Tian 2023-05-22  30  		rc = iommu_attach_device_pasid(hwpt->domain, idev->dev, pasid);
0fb50342800a86 Kevin Tian 2023-05-22  31  	else
0fb50342800a86 Kevin Tian 2023-05-22  32  		/* FIXEME: need a pasid replace IOMMU API */
0fb50342800a86 Kevin Tian 2023-05-22  33  		rc = iommu_attach_device_pasid(hwpt->domain, idev->dev, pasid);
0fb50342800a86 Kevin Tian 2023-05-22  34  	if (rc)
0fb50342800a86 Kevin Tian 2023-05-22  35  		return rc;
0fb50342800a86 Kevin Tian 2023-05-22  36  
0fb50342800a86 Kevin Tian 2023-05-22  37  	xa_store(&idev->pasid_hwpts, pasid, hwpt, GFP_KERNEL);
0fb50342800a86 Kevin Tian 2023-05-22  38  	refcount_inc(&hwpt->obj.users);
0fb50342800a86 Kevin Tian 2023-05-22  39  	return 0;
0fb50342800a86 Kevin Tian 2023-05-22  40  }
0fb50342800a86 Kevin Tian 2023-05-22  41  

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