linux/drivers/gpu/drm/ttm/ttm_execbuf_util.c
Thomas Hellstrom c078aa2fc4 drm/ttm: Add TTM execbuf utilities.
Utilities to reserve, unreserve and fence a list of TTM
buffer objects in a deadlock-safe manner.

Used by the vmwgfx driver.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
2009-12-07 15:22:05 +10:00

118 lines
3.6 KiB
C

/**************************************************************************
*
* 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.
*
**************************************************************************/
#include "ttm/ttm_execbuf_util.h"
#include "ttm/ttm_bo_driver.h"
#include "ttm/ttm_placement.h"
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/module.h>
void ttm_eu_backoff_reservation(struct list_head *list)
{
struct ttm_validate_buffer *entry;
list_for_each_entry(entry, list, head) {
struct ttm_buffer_object *bo = entry->bo;
if (!entry->reserved)
continue;
entry->reserved = false;
ttm_bo_unreserve(bo);
}
}
EXPORT_SYMBOL(ttm_eu_backoff_reservation);
/*
* Reserve buffers for validation.
*
* If a buffer in the list is marked for CPU access, we back off and
* wait for that buffer to become free for GPU access.
*
* If a buffer is reserved for another validation, the validator with
* the highest validation sequence backs off and waits for that buffer
* to become unreserved. This prevents deadlocks when validating multiple
* buffers in different orders.
*/
int ttm_eu_reserve_buffers(struct list_head *list, uint32_t val_seq)
{
struct ttm_validate_buffer *entry;
int ret;
retry:
list_for_each_entry(entry, list, head) {
struct ttm_buffer_object *bo = entry->bo;
entry->reserved = false;
ret = ttm_bo_reserve(bo, true, false, true, val_seq);
if (ret != 0) {
ttm_eu_backoff_reservation(list);
if (ret == -EAGAIN) {
ret = ttm_bo_wait_unreserved(bo, true);
if (unlikely(ret != 0))
return ret;
goto retry;
} else
return ret;
}
entry->reserved = true;
if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
ttm_eu_backoff_reservation(list);
ret = ttm_bo_wait_cpu(bo, false);
if (ret)
return ret;
goto retry;
}
}
return 0;
}
EXPORT_SYMBOL(ttm_eu_reserve_buffers);
void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
{
struct ttm_validate_buffer *entry;
list_for_each_entry(entry, list, head) {
struct ttm_buffer_object *bo = entry->bo;
struct ttm_bo_driver *driver = bo->bdev->driver;
void *old_sync_obj;
spin_lock(&bo->lock);
old_sync_obj = bo->sync_obj;
bo->sync_obj = driver->sync_obj_ref(sync_obj);
bo->sync_obj_arg = entry->new_sync_obj_arg;
spin_unlock(&bo->lock);
ttm_bo_unreserve(bo);
entry->reserved = false;
if (old_sync_obj)
driver->sync_obj_unref(&old_sync_obj);
}
}
EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);