Re: [PATCH v12 07/11] remoteproc: mediatek: Control SCP core 1 by rproc subdevice

[Dan Carpenter]

Hi Tinghan,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Tinghan-Shen/dt-bindings-remoteproc-mediatek-Improve-the-rpmsg-subnode-definition/20230517-123659
base:   git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux.git rproc-next
patch link:    https://lore.kernel.org/r/20230517043449.26352-8-tinghan.shen%40mediatek.com
patch subject: [PATCH v12 07/11] remoteproc: mediatek: Control SCP core 1 by rproc subdevice
config: csky-randconfig-m041-20230517
compiler: csky-linux-gcc (GCC) 12.1.0

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <error27@xxxxxxxxx>
| Closes: https://lore.kernel.org/r/202305181957.ZMXChgJV-lkp@xxxxxxxxx/

smatch warnings:
drivers/remoteproc/mtk_scp.c:891 scp_core_subdev_register() warn: can 'scp_c0' even be NULL?

vim +/scp_c0 +891 drivers/remoteproc/mtk_scp.c

69e1791d92cfa0 Tinghan Shen 2023-05-17  884  static int scp_core_subdev_register(struct mtk_scp *scp)
69e1791d92cfa0 Tinghan Shen 2023-05-17  885  {
69e1791d92cfa0 Tinghan Shen 2023-05-17  886  	struct device *dev = scp->dev;
69e1791d92cfa0 Tinghan Shen 2023-05-17  887  	struct mtk_scp_core_subdev *core_subdev;
69e1791d92cfa0 Tinghan Shen 2023-05-17  888  	struct mtk_scp *scp_c0;
69e1791d92cfa0 Tinghan Shen 2023-05-17  889  
69e1791d92cfa0 Tinghan Shen 2023-05-17  890  	scp_c0 = list_first_entry(scp->cluster, struct mtk_scp, elem);
69e1791d92cfa0 Tinghan Shen 2023-05-17 @891  	if (!scp_c0)
69e1791d92cfa0 Tinghan Shen 2023-05-17  892  		return -ENODATA;

This NULL check isn't right.  Use list_first_entry_or_null() if the list
can be empty.

69e1791d92cfa0 Tinghan Shen 2023-05-17  893  
69e1791d92cfa0 Tinghan Shen 2023-05-17  894  	core_subdev = devm_kzalloc(dev, sizeof(*core_subdev), GFP_KERNEL);
69e1791d92cfa0 Tinghan Shen 2023-05-17  895  	if (!core_subdev)
69e1791d92cfa0 Tinghan Shen 2023-05-17  896  		return -ENOMEM;
69e1791d92cfa0 Tinghan Shen 2023-05-17  897  
69e1791d92cfa0 Tinghan Shen 2023-05-17  898  	core_subdev->scp = scp;
69e1791d92cfa0 Tinghan Shen 2023-05-17  899  	core_subdev->subdev.start = scp_core_subdev_start;
69e1791d92cfa0 Tinghan Shen 2023-05-17  900  	core_subdev->subdev.stop = scp_core_subdev_stop;
69e1791d92cfa0 Tinghan Shen 2023-05-17  901  
69e1791d92cfa0 Tinghan Shen 2023-05-17  902  	scp->core_subdev = core_subdev;
69e1791d92cfa0 Tinghan Shen 2023-05-17  903  	rproc_add_subdev(scp_c0->rproc, &scp->core_subdev->subdev);
69e1791d92cfa0 Tinghan Shen 2023-05-17  904  
69e1791d92cfa0 Tinghan Shen 2023-05-17  905  	return 0;
69e1791d92cfa0 Tinghan Shen 2023-05-17  906  }

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