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/*
* Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst)
*
* Based on bo.c which bears the following copyright notice,
* but is dual licensed:
*
* 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,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/*
* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
*/
#include <linux/reservation.h>
#include <linux/export.h>
DEFINE_WW_CLASS(reservation_ww_class);
EXPORT_SYMBOL(reservation_ww_class);
/*
* Reserve space to add a shared fence to a reservation_object,
* must be called with obj->lock held.
*/
int reservation_object_reserve_shared(struct reservation_object *obj)
{
struct reservation_object_list *fobj, *old;
u32 max;
old = reservation_object_get_list(obj);
if (old && old->shared_max) {
if (old->shared_count < old->shared_max) {
/* perform an in-place update */
kfree(obj->staged);
obj->staged = NULL;
return 0;
} else
max = old->shared_max * 2;
} else
max = 4;
/*
* resize obj->staged or allocate if it doesn't exist,
* noop if already correct size
*/
fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]),
GFP_KERNEL);
if (!fobj)
return -ENOMEM;
obj->staged = fobj;
fobj->shared_max = max;
return 0;
}
EXPORT_SYMBOL(reservation_object_reserve_shared);
static void
reservation_object_add_shared_inplace(struct reservation_object *obj,
struct reservation_object_list *fobj,
struct fence *fence)
{
u32 i;
for (i = 0; i < fobj->shared_count; ++i) {
if (fobj->shared[i]->context == fence->context) {
struct fence *old_fence = fobj->shared[i];
fence_get(fence);
fobj->shared[i] = fence;
fence_put(old_fence);
return;
}
}
fence_get(fence);
fobj->shared[fobj->shared_count] = fence;
/*
* make the new fence visible before incrementing
* fobj->shared_count
*/
smp_wmb();
fobj->shared_count++;
}
static void
reservation_object_add_shared_replace(struct reservation_object *obj,
struct reservation_object_list *old,
struct reservation_object_list *fobj,
struct fence *fence)
{
unsigned i;
fence_get(fence);
if (!old) {
fobj->shared[0] = fence;
fobj->shared_count = 1;
goto done;
}
/*
* no need to bump fence refcounts, rcu_read access
* requires the use of kref_get_unless_zero, and the
* references from the old struct are carried over to
* the new.
*/
fobj->shared_count = old->shared_count;
for (i = 0; i < old->shared_count; ++i) {
if (fence && old->shared[i]->context == fence->context) {
fence_put(old->shared[i]);
fobj->shared[i] = fence;
fence = NULL;
} else
fobj->shared[i] = old->shared[i];
}
if (fence)
fobj->shared[fobj->shared_count++] = fence;
done:
obj->fence = fobj;
kfree(old);
}
/*
* Add a fence to a shared slot, obj->lock must be held, and
* reservation_object_reserve_shared_fence has been called.
*/
void reservation_object_add_shared_fence(struct reservation_object *obj,
struct fence *fence)
{
struct reservation_object_list *old, *fobj = obj->staged;
old = reservation_object_get_list(obj);
obj->staged = NULL;
if (!fobj) {
BUG_ON(old->shared_count == old->shared_max);
reservation_object_add_shared_inplace(obj, old, fence);
} else
reservation_object_add_shared_replace(obj, old, fobj, fence);
}
EXPORT_SYMBOL(reservation_object_add_shared_fence);
void reservation_object_add_excl_fence(struct reservation_object *obj,
struct fence *fence)
{
struct fence *old_fence = obj->fence_excl;
struct reservation_object_list *old;
u32 i = 0;
old = reservation_object_get_list(obj);
if (old) {
i = old->shared_count;
old->shared_count = 0;
}
if (fence)
fence_get(fence);
obj->fence_excl = fence;
/* inplace update, no shared fences */
while (i--)
fence_put(old->shared[i]);
if (old_fence)
fence_put(old_fence);
}
EXPORT_SYMBOL(reservation_object_add_excl_fence);
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