drivers/iommu/mtk_iommu_v1.c:487 mtk_iommu_v1_probe_device() error: we previously assumed 'fwspec' could be null (see line 465)

[kernel test robot <lkp@intel.com>]

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
CC: linux-kernel@vger.kernel.org
TO: Robin Murphy <robin.murphy@arm.com>
CC: Joerg Roedel <jroedel@suse.de>
CC: Jason Gunthorpe <jgg@nvidia.com>
CC: Jerry Snitselaar <jsnitsel@redhat.com>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   715ca9dd687f89ddaac8ec8ccb3b5e5a30311a99
commit: e7080665c977ea1aafb8547a9c7bd08b199311d6 iommu: Clean up open-coded ownership checks
date:   11 months ago
:::::: branch date: 8 hours ago
:::::: commit date: 11 months ago
config: arm-randconfig-r072-20241016 (https://download.01.org/0day-ci/archive/20241020/202410201535.n0b34Sb1-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 14.1.0

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 <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202410201535.n0b34Sb1-lkp@intel.com/

smatch warnings:
drivers/iommu/mtk_iommu_v1.c:487 mtk_iommu_v1_probe_device() error: we previously assumed 'fwspec' could be null (see line 465)

vim +/fwspec +487 drivers/iommu/mtk_iommu_v1.c

b17336c55d8928 Honghui Zhang 2016-06-08  451  
ad9b10e533f6fb Yong Wu       2022-05-03  452  static struct iommu_device *mtk_iommu_v1_probe_device(struct device *dev)
b17336c55d8928 Honghui Zhang 2016-06-08  453  {
a9bf2eec5a6fc0 Joerg Roedel  2018-11-29  454  	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
b17336c55d8928 Honghui Zhang 2016-06-08  455  	struct of_phandle_args iommu_spec;
ad9b10e533f6fb Yong Wu       2022-05-03  456  	struct mtk_iommu_v1_data *data;
635319a4a7444c Yong Wu       2022-01-17  457  	int err, idx = 0, larbid, larbidx;
635319a4a7444c Yong Wu       2022-01-17  458  	struct device_link *link;
635319a4a7444c Yong Wu       2022-01-17  459  	struct device *larbdev;
b17336c55d8928 Honghui Zhang 2016-06-08  460  
822a2ed8c606ca Yong Wu       2022-01-17  461  	/*
822a2ed8c606ca Yong Wu       2022-01-17  462  	 * In the deferred case, free the existed fwspec.
822a2ed8c606ca Yong Wu       2022-01-17  463  	 * Always initialize the fwspec internally.
822a2ed8c606ca Yong Wu       2022-01-17  464  	 */
822a2ed8c606ca Yong Wu       2022-01-17 @465  	if (fwspec) {
822a2ed8c606ca Yong Wu       2022-01-17  466  		iommu_fwspec_free(dev);
822a2ed8c606ca Yong Wu       2022-01-17  467  		fwspec = dev_iommu_fwspec_get(dev);
822a2ed8c606ca Yong Wu       2022-01-17  468  	}
822a2ed8c606ca Yong Wu       2022-01-17  469  
f90a9a85fb946e Yong Wu       2021-04-12  470  	while (!of_parse_phandle_with_args(dev->of_node, "iommus",
f90a9a85fb946e Yong Wu       2021-04-12  471  					   "#iommu-cells",
f90a9a85fb946e Yong Wu       2021-04-12  472  					   idx, &iommu_spec)) {
b17336c55d8928 Honghui Zhang 2016-06-08  473  
ad9b10e533f6fb Yong Wu       2022-05-03  474  		err = mtk_iommu_v1_create_mapping(dev, &iommu_spec);
f90a9a85fb946e Yong Wu       2021-04-12  475  		of_node_put(iommu_spec.np);
f90a9a85fb946e Yong Wu       2021-04-12  476  		if (err)
f90a9a85fb946e Yong Wu       2021-04-12  477  			return ERR_PTR(err);
da5d2748e4a451 Joerg Roedel  2019-01-23  478  
da5d2748e4a451 Joerg Roedel  2019-01-23  479  		/* dev->iommu_fwspec might have changed */
da5d2748e4a451 Joerg Roedel  2019-01-23  480  		fwspec = dev_iommu_fwspec_get(dev);
f90a9a85fb946e Yong Wu       2021-04-12  481  		idx++;
b17336c55d8928 Honghui Zhang 2016-06-08  482  	}
b17336c55d8928 Honghui Zhang 2016-06-08  483  
57dbf81f50c82a Joerg Roedel  2020-04-29  484  	data = dev_iommu_priv_get(dev);
b17336c55d8928 Honghui Zhang 2016-06-08  485  
635319a4a7444c Yong Wu       2022-01-17  486  	/* Link the consumer device with the smi-larb device(supplier) */
635319a4a7444c Yong Wu       2022-01-17 @487  	larbid = mt2701_m4u_to_larb(fwspec->ids[0]);
de78657e16f414 Miles Chen    2022-05-05  488  	if (larbid >= MT2701_LARB_NR_MAX)
de78657e16f414 Miles Chen    2022-05-05  489  		return ERR_PTR(-EINVAL);
de78657e16f414 Miles Chen    2022-05-05  490  
635319a4a7444c Yong Wu       2022-01-17  491  	for (idx = 1; idx < fwspec->num_ids; idx++) {
635319a4a7444c Yong Wu       2022-01-17  492  		larbidx = mt2701_m4u_to_larb(fwspec->ids[idx]);
635319a4a7444c Yong Wu       2022-01-17  493  		if (larbid != larbidx) {
635319a4a7444c Yong Wu       2022-01-17  494  			dev_err(dev, "Can only use one larb. Fail@larb%d-%d.\n",
635319a4a7444c Yong Wu       2022-01-17  495  				larbid, larbidx);
635319a4a7444c Yong Wu       2022-01-17  496  			return ERR_PTR(-EINVAL);
635319a4a7444c Yong Wu       2022-01-17  497  		}
635319a4a7444c Yong Wu       2022-01-17  498  	}
635319a4a7444c Yong Wu       2022-01-17  499  
635319a4a7444c Yong Wu       2022-01-17  500  	larbdev = data->larb_imu[larbid].dev;
de78657e16f414 Miles Chen    2022-05-05  501  	if (!larbdev)
de78657e16f414 Miles Chen    2022-05-05  502  		return ERR_PTR(-EINVAL);
de78657e16f414 Miles Chen    2022-05-05  503  
635319a4a7444c Yong Wu       2022-01-17  504  	link = device_link_add(dev, larbdev,
635319a4a7444c Yong Wu       2022-01-17  505  			       DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS);
635319a4a7444c Yong Wu       2022-01-17  506  	if (!link)
635319a4a7444c Yong Wu       2022-01-17  507  		dev_err(dev, "Unable to link %s\n", dev_name(larbdev));
635319a4a7444c Yong Wu       2022-01-17  508  
57dbf81f50c82a Joerg Roedel  2020-04-29  509  	return &data->iommu;
57dbf81f50c82a Joerg Roedel  2020-04-29  510  }
57dbf81f50c82a Joerg Roedel  2020-04-29  511  

:::::: The code at line 487 was first introduced by commit
:::::: 635319a4a7444ca97124d781cd96deb277ff4d40 media: iommu/mediatek: Add device_link between the consumer and the larb devices

:::::: TO: Yong Wu <yong.wu@mediatek.com>
:::::: CC: Mauro Carvalho Chehab <mchehab@kernel.org>

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