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Subject: Re: [PATCH v8 1/5] vfio/migration: Add debugfs to live migration
 driver
To:     Jason Gunthorpe <jgg@nvidia.com>
CC:     <alex.williamson@redhat.com>,
        <shameerali.kolothum.thodi@huawei.com>,
        <jonathan.cameron@huawei.com>, <cohuck@redhat.com>,
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References: <20230217084831.35783-1-liulongfang@huawei.com>
 <20230217084831.35783-2-liulongfang@huawei.com> <ZAtlGDGZvBMMvE9R@nvidia.com>
From:   liulongfang <liulongfang@huawei.com>
Message-ID: <b3f69fa5-b31e-f625-fc75-b655edb5f0c3@huawei.com>
Date:   Tue, 14 Mar 2023 17:32:00 +0800
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On 2023/3/11 1:12, Jason Gunthorpe wrote:
> On Fri, Feb 17, 2023 at 04:48:27PM +0800, Longfang Liu wrote:
>> +void vfio_vf_debugfs_init(struct vfio_device *vdev)
>> +{
>> +	struct device *dev = &vdev->device;
>> +
>> +	vdev->debug_root = debugfs_create_dir(dev_name(vdev->dev), vfio_debugfs_root);
>> +
>> +	debugfs_create_devm_seqfile(dev, "migration_state", vdev->debug_root,
>> +				  vfio_vf_state_read);
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_vf_debugfs_init);
>> +
>> +void vfio_vf_debugfs_exit(struct vfio_device *vdev)
>> +{
>> +	debugfs_remove_recursive(vdev->debug_root);
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_vf_debugfs_exit);
>> +
>> +void  vfio_debugfs_create_root(void)
>> +{
>> +	vfio_debugfs_root = debugfs_create_dir("vfio", NULL);
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_debugfs_create_root);
>> +
>> +void  vfio_debugfs_remove_root(void)
>> +{
>> +	debugfs_remove_recursive(vfio_debugfs_root);
>> +	vfio_debugfs_root = NULL;
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_debugfs_remove_root);
> 
> Why are these symbols exported?
> 

If the export statement is not added, a compilation error will occur:

ERROR: modpost: "vfio_vf_debugfs_init" [drivers/vfio/pci/hisilicon/hisi-acc-vfio-pci.ko] undefined!
ERROR: modpost: "vfio_vf_debugfs_exit" [drivers/vfio/pci/hisilicon/hisi-acc-vfio-pci.ko] undefined!
scripts/Makefile.modpost:126: recipe for target 'Module.symvers' failed
make[1]: *** [Module.symvers] Error 1


> Jason
> 
> .
Thanks,
Longfang

>