linux/drivers/vfio/pci/pds/vfio_dev.h
Brett Creeley 6a7e448c6b vfio/pds: Refactor/simplify reset logic
The current logic for handling resets is more complicated than it needs
to be. The deferred_reset flag is used to indicate a reset is needed
and the deferred_reset_state is the requested, post-reset, state.

Also, the deferred_reset logic was added to vfio migration drivers to
prevent a circular locking dependency with respect to mm_lock and state
mutex. This is mainly because of the copy_to/from_user() functions(which
takes mm_lock) invoked under state mutex.

Remove all of the deferred reset logic and just pass the requested
next state to pds_vfio_reset() so it can be used for VMM and DSC
initiated resets.

This removes the need for pds_vfio_state_mutex_lock(), so remove that
and replace its use with a simple mutex_unlock().

Also, remove the reset_mutex as it's no longer needed since the
state_mutex can be the driver's primary protector.

Suggested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Link: https://lore.kernel.org/r/20240308182149.22036-3-brett.creeley@amd.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2024-03-11 12:10:37 -06:00

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C

/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright(c) 2023 Advanced Micro Devices, Inc. */
#ifndef _VFIO_DEV_H_
#define _VFIO_DEV_H_
#include <linux/pci.h>
#include <linux/vfio_pci_core.h>
#include "dirty.h"
#include "lm.h"
struct pds_vfio_pci_device {
struct vfio_pci_core_device vfio_coredev;
struct pds_vfio_lm_file *save_file;
struct pds_vfio_lm_file *restore_file;
struct pds_vfio_dirty dirty;
struct mutex state_mutex; /* protect migration state */
enum vfio_device_mig_state state;
struct notifier_block nb;
int vf_id;
u16 client_id;
};
const struct vfio_device_ops *pds_vfio_ops_info(void);
struct pds_vfio_pci_device *pds_vfio_pci_drvdata(struct pci_dev *pdev);
void pds_vfio_reset(struct pds_vfio_pci_device *pds_vfio,
enum vfio_device_mig_state state);
struct pci_dev *pds_vfio_to_pci_dev(struct pds_vfio_pci_device *pds_vfio);
struct device *pds_vfio_to_dev(struct pds_vfio_pci_device *pds_vfio);
#endif /* _VFIO_DEV_H_ */