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linux-next/include/linux/mdev.h
Paul Gortmaker c6ef7fd40e vfio-mdev: fix non-standard ioctl return val causing i386 build fail
What appears to be a copy and paste error from the line above gets
the ioctl a ssize_t return value instead of the traditional "int".

The associated sample code used "long" which meant it would compile
for x86-64 but not i386, with the latter failing as follows:

  CC [M]  samples/vfio-mdev/mtty.o
samples/vfio-mdev/mtty.c:1418:20: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
  .ioctl          = mtty_ioctl,
                    ^
samples/vfio-mdev/mtty.c:1418:20: note: (near initialization for ‘mdev_fops.ioctl’)
cc1: some warnings being treated as errors

Since in this case, vfio is working with struct file_operations; as such:

    long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
    long (*compat_ioctl) (struct file *, unsigned int, unsigned long);

...and so here we just standardize on long vs. the normal int that user
space typically sees and documents as per "man ioctl" and similar.

Fixes: 9d1a546c53 ("docs: Sample driver to demonstrate how to use Mediated device framework.")
Cc: Kirti Wankhede <kwankhede@nvidia.com>
Cc: Neo Jia <cjia@nvidia.com>
Cc: kvm@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2017-01-04 13:22:38 -07:00

139 lines
4.9 KiB
C

/*
* Mediated device definition
*
* Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
* Author: Neo Jia <cjia@nvidia.com>
* Kirti Wankhede <kwankhede@nvidia.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef MDEV_H
#define MDEV_H
struct mdev_device;
/**
* struct mdev_parent_ops - Structure to be registered for each parent device to
* register the device to mdev module.
*
* @owner: The module owner.
* @dev_attr_groups: Attributes of the parent device.
* @mdev_attr_groups: Attributes of the mediated device.
* @supported_type_groups: Attributes to define supported types. It is mandatory
* to provide supported types.
* @create: Called to allocate basic resources in parent device's
* driver for a particular mediated device. It is
* mandatory to provide create ops.
* @kobj: kobject of type for which 'create' is called.
* @mdev: mdev_device structure on of mediated device
* that is being created
* Returns integer: success (0) or error (< 0)
* @remove: Called to free resources in parent device's driver for a
* a mediated device. It is mandatory to provide 'remove'
* ops.
* @mdev: mdev_device device structure which is being
* destroyed
* Returns integer: success (0) or error (< 0)
* @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
* Parent device that support mediated device should be registered with mdev
* module with mdev_parent_ops structure.
**/
struct mdev_parent_ops {
struct module *owner;
const struct attribute_group **dev_attr_groups;
const struct attribute_group **mdev_attr_groups;
struct attribute_group **supported_type_groups;
int (*create)(struct kobject *kobj, struct mdev_device *mdev);
int (*remove)(struct mdev_device *mdev);
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);
};
/* interface for exporting mdev supported type attributes */
struct mdev_type_attribute {
struct attribute attr;
ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
ssize_t (*store)(struct kobject *kobj, struct device *dev,
const char *buf, size_t count);
};
#define MDEV_TYPE_ATTR(_name, _mode, _show, _store) \
struct mdev_type_attribute mdev_type_attr_##_name = \
__ATTR(_name, _mode, _show, _store)
#define MDEV_TYPE_ATTR_RW(_name) \
struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RW(_name)
#define MDEV_TYPE_ATTR_RO(_name) \
struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_RO(_name)
#define MDEV_TYPE_ATTR_WO(_name) \
struct mdev_type_attribute mdev_type_attr_##_name = __ATTR_WO(_name)
/**
* struct mdev_driver - Mediated device driver
* @name: driver name
* @probe: called when new device created
* @remove: called when device removed
* @driver: device driver structure
*
**/
struct mdev_driver {
const char *name;
int (*probe)(struct device *dev);
void (*remove)(struct device *dev);
struct device_driver driver;
};
#define to_mdev_driver(drv) container_of(drv, struct mdev_driver, driver)
extern void *mdev_get_drvdata(struct mdev_device *mdev);
extern void mdev_set_drvdata(struct mdev_device *mdev, void *data);
extern uuid_le mdev_uuid(struct mdev_device *mdev);
extern struct bus_type mdev_bus_type;
extern int mdev_register_device(struct device *dev,
const struct mdev_parent_ops *ops);
extern void mdev_unregister_device(struct device *dev);
extern int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
extern void mdev_unregister_driver(struct mdev_driver *drv);
extern struct device *mdev_parent_dev(struct mdev_device *mdev);
extern struct device *mdev_dev(struct mdev_device *mdev);
extern struct mdev_device *mdev_from_dev(struct device *dev);
#endif /* MDEV_H */