/**************************************************************************
*
* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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**************************************************************************/
/*
* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
*/
#ifndef _TTM_EXECBUF_UTIL_H_
#define _TTM_EXECBUF_UTIL_H_
#include <ttm/ttm_bo_api.h>
#include <linux/list.h>
/**
* struct ttm_validate_buffer
*
* @head: list head for thread-private list.
* @bo: refcounted buffer object pointer.
* @reserved: Indicates whether @bo has been reserved for validation.
* @removed: Indicates whether @bo has been removed from lru lists.
* @put_count: Number of outstanding references on bo::list_kref.
* @old_sync_obj: Pointer to a sync object about to be unreferenced
*/
struct ttm_validate_buffer {
struct list_head head;
struct ttm_buffer_object *bo;
bool reserved;
bool removed;
int put_count;
void *old_sync_obj;
};
/**
* function ttm_eu_backoff_reservation
*
* @list: thread private list of ttm_validate_buffer structs.
*
* Undoes all buffer validation reservations for bos pointed to by
* the list entries.
*/
extern void ttm_eu_backoff_reservation(struct list_head *list);
/**
* function ttm_eu_reserve_buffers
*
* @list: thread private list of ttm_validate_buffer structs.
*
* Tries to reserve bos pointed to by the list entries for validation.
* If the function returns 0, all buffers are marked as "unfenced",
* taken off the lru lists and are not synced for write CPU usage.
*
* If the function detects a deadlock due to multiple threads trying to
* reserve the same buffers in reverse order, all threads except one will
* back off and retry. This function may sleep while waiting for
* CPU write reservations to be cleared, and for other threads to
* unreserve their buffers.
*
* This function may return -ERESTART or -EAGAIN if the calling process
* receives a signal while waiting. In that case, no buffers on the list
* will be reserved upon return.
*
* Buffers reserved by this function should be unreserved by
* a call to either ttm_eu_backoff_reservation() or
* ttm_eu_fence_buffer_objects() when command submission is complete or
* has failed.
*/
extern int ttm_eu_reserve_buffers(struct list_head *list);
/**
* function ttm_eu_fence_buffer_objects.
*
* @list: thread private list of ttm_validate_buffer structs.
* @sync_obj: The new sync object for the buffers.
*
* This function should be called when command submission is complete, and
* it will add a new sync object to bos pointed to by entries on @list.
* It also unreserves all buffers, putting them on lru lists.
*
*/
extern void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj);
#endif