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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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c078aa2fc4
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>
118 lines
3.6 KiB
C
118 lines
3.6 KiB
C
/**************************************************************************
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*
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* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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**************************************************************************/
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#include "ttm/ttm_execbuf_util.h"
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#include "ttm/ttm_bo_driver.h"
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#include "ttm/ttm_placement.h"
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#include <linux/wait.h>
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#include <linux/sched.h>
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#include <linux/module.h>
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void ttm_eu_backoff_reservation(struct list_head *list)
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{
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struct ttm_validate_buffer *entry;
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list_for_each_entry(entry, list, head) {
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struct ttm_buffer_object *bo = entry->bo;
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if (!entry->reserved)
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continue;
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entry->reserved = false;
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ttm_bo_unreserve(bo);
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}
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}
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EXPORT_SYMBOL(ttm_eu_backoff_reservation);
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/*
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* Reserve buffers for validation.
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*
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* If a buffer in the list is marked for CPU access, we back off and
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* wait for that buffer to become free for GPU access.
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*
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* If a buffer is reserved for another validation, the validator with
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* the highest validation sequence backs off and waits for that buffer
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* to become unreserved. This prevents deadlocks when validating multiple
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* buffers in different orders.
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*/
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int ttm_eu_reserve_buffers(struct list_head *list, uint32_t val_seq)
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{
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struct ttm_validate_buffer *entry;
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int ret;
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retry:
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list_for_each_entry(entry, list, head) {
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struct ttm_buffer_object *bo = entry->bo;
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entry->reserved = false;
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ret = ttm_bo_reserve(bo, true, false, true, val_seq);
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if (ret != 0) {
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ttm_eu_backoff_reservation(list);
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if (ret == -EAGAIN) {
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ret = ttm_bo_wait_unreserved(bo, true);
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if (unlikely(ret != 0))
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return ret;
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goto retry;
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} else
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return ret;
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}
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entry->reserved = true;
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if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
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ttm_eu_backoff_reservation(list);
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ret = ttm_bo_wait_cpu(bo, false);
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if (ret)
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return ret;
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goto retry;
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}
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}
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return 0;
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}
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EXPORT_SYMBOL(ttm_eu_reserve_buffers);
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void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
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{
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struct ttm_validate_buffer *entry;
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list_for_each_entry(entry, list, head) {
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struct ttm_buffer_object *bo = entry->bo;
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struct ttm_bo_driver *driver = bo->bdev->driver;
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void *old_sync_obj;
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spin_lock(&bo->lock);
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old_sync_obj = bo->sync_obj;
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bo->sync_obj = driver->sync_obj_ref(sync_obj);
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bo->sync_obj_arg = entry->new_sync_obj_arg;
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spin_unlock(&bo->lock);
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ttm_bo_unreserve(bo);
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entry->reserved = false;
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if (old_sync_obj)
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driver->sync_obj_unref(&old_sync_obj);
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}
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}
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EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
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