RE: [PATCH V6 3/6] mdev: introduce device specific ops

[Parav Pandit]

> -----Original Message-----
> From: Jason Wang <jasowang@xxxxxxxxxx>
> Sent: Wednesday, October 30, 2019 1:45 AM
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> Subject: [PATCH V6 3/6] mdev: introduce device specific ops
> 
> Currently, except for the create and remove, the rest of mdev_parent_ops is
> designed for vfio-mdev driver only and may not help for kernel mdev driver.
> With the help of class id, this patch introduces device specific callbacks inside
> mdev_device structure. This allows different set of callback to be used by vfio-
> mdev and virtio-mdev.
> 
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
[ ..]

> diff --git a/include/linux/vfio_mdev_ops.h b/include/linux/vfio_mdev_ops.h
> new file mode 100644 index 000000000000..3907c5371c2b
> --- /dev/null
> +++ b/include/linux/vfio_mdev_ops.h
> @@ -0,0 +1,52 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * VFIO Mediated device definition
> + */
> +
> +#ifndef VFIO_MDEV_H
> +#define VFIO_MDEV_H
> +
I should have noticed this before. :-(
APIs exposed are by the mdev module and named with mdev_ prefix.
And file name is _ops.h,

We should name this file as mdev_vfio_ops.h

And #define should be MDEV_VFIO_OPS_H

> +#include <linux/mdev.h>
> +
> +/**
> + * struct vfio_mdev_device_ops - Structure to be registered for each
s/vfio_mdev_device_ops/mdev_vfio_device_ops/

Similarly for virtio in future patches.

> + * mdev device to register the device to vfio-mdev module.
> + *
> + * @open:		Open mediated device.
> + *			@mdev: mediated device.
> + *			Returns integer: success (0) or error (< 0)
> + * @release:		release mediated device
> + *			@mdev: mediated device.
> + * @read:		Read emulation callback
> + *			@mdev: mediated device structure
> + *			@buf: read buffer
> + *			@count: number of bytes to read
> + *			@ppos: address.
> + *			Retuns number on bytes read on success or error.
> + * @write:		Write emulation callback
> + *			@mdev: mediated device structure
> + *			@buf: write buffer
> + *			@count: number of bytes to be written
> + *			@ppos: address.
> + *			Retuns number on bytes written on success or error.
> + * @ioctl:		IOCTL callback
> + *			@mdev: mediated device structure
> + *			@cmd: ioctl command
> + *			@arg: arguments to ioctl
> + * @mmap:		mmap callback
> + *			@mdev: mediated device structure
> + *			@vma: vma structure
> + */
> +struct vfio_mdev_device_ops {
> +	int     (*open)(struct mdev_device *mdev);
> +	void    (*release)(struct mdev_device *mdev);
> +	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
> +			size_t count, loff_t *ppos);
> +	ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
> +			 size_t count, loff_t *ppos);
> +	long	(*ioctl)(struct mdev_device *mdev, unsigned int cmd,
> +			 unsigned long arg);
> +	int	(*mmap)(struct mdev_device *mdev, struct vm_area_struct
> *vma);
> +};
> +
> +#endif
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c index
> 115bc5074656..1afec20bf0c5 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -30,6 +30,7 @@
>  #include <linux/iommu.h>
>  #include <linux/sysfs.h>
>  #include <linux/mdev.h>
> +#include <linux/vfio_mdev_ops.h>
>  #include <linux/pci.h>
>  #include <linux/dma-buf.h>
>  #include <linux/highmem.h>
> @@ -516,6 +517,8 @@ static int mbochs_reset(struct mdev_device *mdev)
>  	return 0;
>  }
> 
> +static const struct vfio_mdev_device_ops vfio_mdev_ops;
> +
>  static int mbochs_create(struct kobject *kobj, struct mdev_device *mdev)  {
>  	const struct mbochs_type *type = mbochs_find_type(kobj); @@ -561,7
> +564,7 @@ static int mbochs_create(struct kobject *kobj, struct mdev_device
> *mdev)
>  	mbochs_reset(mdev);
> 
>  	mbochs_used_mbytes += type->mbytes;
> -	mdev_set_class(mdev, MDEV_CLASS_ID_VFIO);
> +	mdev_set_vfio_ops(mdev, &vfio_mdev_ops);
>  	return 0;
> 
>  err_mem:
> @@ -1419,12 +1422,7 @@ static struct attribute_group *mdev_type_groups[]
> = {
>  	NULL,
>  };
> 
> -static const struct mdev_parent_ops mdev_fops = {
> -	.owner			= THIS_MODULE,
> -	.mdev_attr_groups	= mdev_dev_groups,
> -	.supported_type_groups	= mdev_type_groups,
> -	.create			= mbochs_create,
> -	.remove			= mbochs_remove,
> +static const struct vfio_mdev_device_ops vfio_mdev_ops = {
>  	.open			= mbochs_open,
>  	.release		= mbochs_close,
>  	.read			= mbochs_read,
> @@ -1433,6 +1431,14 @@ static const struct mdev_parent_ops mdev_fops = {
>  	.mmap			= mbochs_mmap,
>  };
> 
> +static const struct mdev_parent_ops mdev_fops = {
> +	.owner			= THIS_MODULE,
> +	.mdev_attr_groups	= mdev_dev_groups,
> +	.supported_type_groups	= mdev_type_groups,
> +	.create			= mbochs_create,
> +	.remove			= mbochs_remove,
> +};
> +
>  static const struct file_operations vd_fops = {
>  	.owner		= THIS_MODULE,
>  };
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c index
> 665614574d50..d571fb65f50f 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -26,6 +26,7 @@
>  #include <linux/iommu.h>
>  #include <linux/sysfs.h>
>  #include <linux/mdev.h>
> +#include <linux/vfio_mdev_ops.h>
>  #include <linux/pci.h>
>  #include <drm/drm_fourcc.h>
>  #include "mdpy-defs.h"
> @@ -226,6 +227,8 @@ static int mdpy_reset(struct mdev_device *mdev)
>  	return 0;
>  }
> 
> +static const struct vfio_mdev_device_ops vfio_mdev_ops;
> +
>  static int mdpy_create(struct kobject *kobj, struct mdev_device *mdev)  {
>  	const struct mdpy_type *type = mdpy_find_type(kobj); @@ -269,7
> +272,7 @@ static int mdpy_create(struct kobject *kobj, struct mdev_device
> *mdev)
>  	mdpy_reset(mdev);
> 
>  	mdpy_count++;
> -	mdev_set_class(mdev, MDEV_CLASS_ID_VFIO);
> +	mdev_set_vfio_ops(mdev, &vfio_mdev_ops);
>  	return 0;
>  }
> 
> @@ -726,12 +729,7 @@ static struct attribute_group *mdev_type_groups[] = {
>  	NULL,
>  };
> 
> -static const struct mdev_parent_ops mdev_fops = {
> -	.owner			= THIS_MODULE,
> -	.mdev_attr_groups	= mdev_dev_groups,
> -	.supported_type_groups	= mdev_type_groups,
> -	.create			= mdpy_create,
> -	.remove			= mdpy_remove,
> +static const struct vfio_mdev_device_ops vfio_mdev_ops = {
>  	.open			= mdpy_open,
>  	.release		= mdpy_close,
>  	.read			= mdpy_read,
> @@ -740,6 +738,14 @@ static const struct mdev_parent_ops mdev_fops = {
>  	.mmap			= mdpy_mmap,
>  };
> 
> +static const struct mdev_parent_ops mdev_fops = {
> +	.owner			= THIS_MODULE,
> +	.mdev_attr_groups	= mdev_dev_groups,
> +	.supported_type_groups	= mdev_type_groups,
> +	.create			= mdpy_create,
> +	.remove			= mdpy_remove,
> +};
> +
>  static const struct file_operations vd_fops = {
>  	.owner		= THIS_MODULE,
>  };
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c index
> 90da12ff7fd9..4048b242c636 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -27,6 +27,7 @@
>  #include <linux/ctype.h>
>  #include <linux/file.h>
>  #include <linux/mdev.h>
> +#include <linux/vfio_mdev_ops.h>
>  #include <linux/pci.h>
>  #include <linux/serial.h>
>  #include <uapi/linux/serial_reg.h>
> @@ -708,6 +709,8 @@ static ssize_t mdev_access(struct mdev_device *mdev,
> u8 *buf, size_t count,
>  	return ret;
>  }
> 
> +static const struct vfio_mdev_device_ops vfio_dev_ops;
> +
>  static int mtty_create(struct kobject *kobj, struct mdev_device *mdev)  {
>  	struct mdev_state *mdev_state;
> @@ -755,7 +758,7 @@ static int mtty_create(struct kobject *kobj, struct
> mdev_device *mdev)
>  	list_add(&mdev_state->next, &mdev_devices_list);
>  	mutex_unlock(&mdev_list_lock);
> 
> -	mdev_set_class(mdev, MDEV_CLASS_ID_VFIO);
> +	mdev_set_vfio_ops(mdev, &vfio_dev_ops);
>  	return 0;
>  }
> 
> @@ -1388,6 +1391,14 @@ static struct attribute_group *mdev_type_groups[]
> = {
>  	NULL,
>  };
> 
> +static const struct vfio_mdev_device_ops vfio_dev_ops = {
> +	.open		= mtty_open,
> +	.release	= mtty_close,
> +	.read		= mtty_read,
> +	.write		= mtty_write,
> +	.ioctl		= mtty_ioctl,
> +};
> +
>  static const struct mdev_parent_ops mdev_fops = {
>  	.owner                  = THIS_MODULE,
>  	.dev_attr_groups        = mtty_dev_groups,
> @@ -1395,11 +1406,6 @@ static const struct mdev_parent_ops mdev_fops = {
>  	.supported_type_groups  = mdev_type_groups,
>  	.create                 = mtty_create,
>  	.remove			= mtty_remove,
> -	.open                   = mtty_open,
> -	.release                = mtty_close,
> -	.read                   = mtty_read,
> -	.write                  = mtty_write,
> -	.ioctl		        = mtty_ioctl,
>  };
> 
>  static void mtty_device_release(struct device *dev)
> --
> 2.19.1
With above small nit changes to rename the fields and file,

Reviewed-by: Parav Pandit <parav@xxxxxxxxxxxx>