Subject: Re: [PATCH v8 1/5] vfio/migration: Add debugfs to live migration
 driver
From:   liulongfang <liulongfang@huawei.com>
To:     Jason Gunthorpe <jgg@nvidia.com>
CC:     <alex.williamson@redhat.com>,
        <shameerali.kolothum.thodi@huawei.com>,
        <jonathan.cameron@huawei.com>, <cohuck@redhat.com>,
        <linux-kernel@vger.kernel.org>, <linuxarm@openeuler.org>
References: <20230217084831.35783-1-liulongfang@huawei.com>
 <20230217084831.35783-2-liulongfang@huawei.com> <ZAtlGDGZvBMMvE9R@nvidia.com>
 <b3f69fa5-b31e-f625-fc75-b655edb5f0c3@huawei.com>
Message-ID: <b721f417-55aa-2bb0-a223-2118ae4cbc30@huawei.com>
Date:   Tue, 14 Mar 2023 19:31:41 +0800
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On 2023/3/14 17:32, liulongfang wrote:
> 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
> 

The first two functions cannot remove the export statement,
but the latter two can be removed.

Thanks,
Longfang.
> 
>> Jason
>>
>> .
> Thanks,
> Longfang
> 
>>