5e33840511
Now that the code is compatible in semantics, flip the switch. Use ww_mutex instead of the homegrown implementation. ww_mutex uses -EDEADLK to signal that the caller has to back off, and -EALREADY to indicate this buffer is already held by the caller. ttm used -EAGAIN and -EDEADLK for those, respectively. So some changes were needed to handle this correctly. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Reviewed-by: Jerome Glisse <jglisse@redhat.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
115 lines
4.1 KiB
C
115 lines
4.1 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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/*
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* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
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*/
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#ifndef _TTM_EXECBUF_UTIL_H_
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#define _TTM_EXECBUF_UTIL_H_
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#include <ttm/ttm_bo_api.h>
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#include <linux/list.h>
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/**
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* struct ttm_validate_buffer
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*
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* @head: list head for thread-private list.
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* @bo: refcounted buffer object pointer.
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* @reserved: Indicates whether @bo has been reserved for validation.
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* @removed: Indicates whether @bo has been removed from lru lists.
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* @put_count: Number of outstanding references on bo::list_kref.
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* @old_sync_obj: Pointer to a sync object about to be unreferenced
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*/
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struct ttm_validate_buffer {
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struct list_head head;
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struct ttm_buffer_object *bo;
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bool reserved;
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bool removed;
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int put_count;
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void *old_sync_obj;
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};
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/**
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* function ttm_eu_backoff_reservation
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*
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* @ticket: ww_acquire_ctx from reserve call
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* @list: thread private list of ttm_validate_buffer structs.
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*
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* Undoes all buffer validation reservations for bos pointed to by
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* the list entries.
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*/
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extern void ttm_eu_backoff_reservation(struct ww_acquire_ctx *ticket,
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struct list_head *list);
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/**
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* function ttm_eu_reserve_buffers
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*
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* @ticket: [out] ww_acquire_ctx returned by call.
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* @list: thread private list of ttm_validate_buffer structs.
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*
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* Tries to reserve bos pointed to by the list entries for validation.
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* If the function returns 0, all buffers are marked as "unfenced",
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* taken off the lru lists and are not synced for write CPU usage.
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*
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* If the function detects a deadlock due to multiple threads trying to
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* reserve the same buffers in reverse order, all threads except one will
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* back off and retry. This function may sleep while waiting for
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* CPU write reservations to be cleared, and for other threads to
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* unreserve their buffers.
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*
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* This function may return -ERESTART or -EAGAIN if the calling process
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* receives a signal while waiting. In that case, no buffers on the list
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* will be reserved upon return.
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*
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* Buffers reserved by this function should be unreserved by
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* a call to either ttm_eu_backoff_reservation() or
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* ttm_eu_fence_buffer_objects() when command submission is complete or
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* has failed.
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*/
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extern int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
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struct list_head *list);
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/**
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* function ttm_eu_fence_buffer_objects.
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*
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* @ticket: ww_acquire_ctx from reserve call
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* @list: thread private list of ttm_validate_buffer structs.
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* @sync_obj: The new sync object for the buffers.
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*
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* This function should be called when command submission is complete, and
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* it will add a new sync object to bos pointed to by entries on @list.
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* It also unreserves all buffers, putting them on lru lists.
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*
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*/
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extern void ttm_eu_fence_buffer_objects(struct ww_acquire_ctx *ticket,
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struct list_head *list, void *sync_obj);
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#endif
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