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Date:   Fri, 2 Dec 2022 11:17:17 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Longfang Liu <liulongfang@huawei.com>
Cc:     alex.williamson@redhat.com, shameerali.kolothum.thodi@huawei.com,
        john.garry@huawei.com, cohuck@redhat.com,
        linux-kernel@vger.kernel.org, linuxarm@openeuler.org
Subject: Re: [PATCH v4 1/5] vfio/migration: Add debugfs to live migration
 driver
Message-ID: <Y4oW/ToMZEUnlYZ1@nvidia.com>
References: <20221202092625.35075-1-liulongfang@huawei.com>
 <20221202092625.35075-2-liulongfang@huawei.com>
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On Fri, Dec 02, 2022 at 05:26:21PM +0800, Longfang Liu wrote:

> +static ssize_t vfio_pci_vf_state_read(struct file *filp, char __user *buffer,
> +			   size_t count, loff_t *pos)
> +{

This would be better to use debugfs_create_devm_seqfile()

Then you can simply use seq_printf()

> @@ -119,6 +129,8 @@ struct vfio_migration_ops {
>  				   enum vfio_device_mig_state *curr_state);
>  	int (*migration_get_data_size)(struct vfio_device *device,
>  				       unsigned long *stop_copy_length);
> +	int (*migration_get_data)(struct vfio_device *device, char *buffer);
> +	int (*migration_get_attr)(struct vfio_device *device, char
>  				   *buffer);

Still no to passing through debugfs ops, create these files in the
driver.

Jason