forked from luck/tmp_suning_uos_patched
03e4e0a9e0
Ages ago Rob Clark noted, "Currently with fence-array, we have a potential deadlock situation. If we fence_add_callback() on an array-fence, the array-fence's lock is acquired first, and in it's ->enable_signaling() callback, it will install cbs on it's array-member fences, so the array-member's lock is acquired second. But in the signal path, the array-member's lock is acquired first, and the array-fence's lock acquired second." Rob proposed either extensive changes to dma-fence to unnest the fence-array signaling, or to defer the signaling onto a workqueue. This is a more refined version of the later, that should keep the latency of the fence signaling to a minimum by using an irq-work, which is executed asap. Reported-by: Rob Clark <robdclark@gmail.com> Suggested-by: Rob Clark <robdclark@gmail.com> References: 1476635975-21981-1-git-send-email-robdclark@gmail.com Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Rob Clark <robdclark@gmail.com> Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Christian König <christian.koenig@amd.com> Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20171114162719.30958-1-chris@chris-wilson.co.uk
92 lines
2.5 KiB
C
92 lines
2.5 KiB
C
/*
|
|
* fence-array: aggregates fence to be waited together
|
|
*
|
|
* Copyright (C) 2016 Collabora Ltd
|
|
* Copyright (C) 2016 Advanced Micro Devices, Inc.
|
|
* Authors:
|
|
* Gustavo Padovan <gustavo@padovan.org>
|
|
* Christian König <christian.koenig@amd.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 as published by
|
|
* the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
* more details.
|
|
*/
|
|
|
|
#ifndef __LINUX_DMA_FENCE_ARRAY_H
|
|
#define __LINUX_DMA_FENCE_ARRAY_H
|
|
|
|
#include <linux/dma-fence.h>
|
|
#include <linux/irq_work.h>
|
|
|
|
/**
|
|
* struct dma_fence_array_cb - callback helper for fence array
|
|
* @cb: fence callback structure for signaling
|
|
* @array: reference to the parent fence array object
|
|
*/
|
|
struct dma_fence_array_cb {
|
|
struct dma_fence_cb cb;
|
|
struct dma_fence_array *array;
|
|
};
|
|
|
|
/**
|
|
* struct dma_fence_array - fence to represent an array of fences
|
|
* @base: fence base class
|
|
* @lock: spinlock for fence handling
|
|
* @num_fences: number of fences in the array
|
|
* @num_pending: fences in the array still pending
|
|
* @fences: array of the fences
|
|
*/
|
|
struct dma_fence_array {
|
|
struct dma_fence base;
|
|
|
|
spinlock_t lock;
|
|
unsigned num_fences;
|
|
atomic_t num_pending;
|
|
struct dma_fence **fences;
|
|
|
|
struct irq_work work;
|
|
};
|
|
|
|
extern const struct dma_fence_ops dma_fence_array_ops;
|
|
|
|
/**
|
|
* dma_fence_is_array - check if a fence is from the array subsclass
|
|
* @fence: fence to test
|
|
*
|
|
* Return true if it is a dma_fence_array and false otherwise.
|
|
*/
|
|
static inline bool dma_fence_is_array(struct dma_fence *fence)
|
|
{
|
|
return fence->ops == &dma_fence_array_ops;
|
|
}
|
|
|
|
/**
|
|
* to_dma_fence_array - cast a fence to a dma_fence_array
|
|
* @fence: fence to cast to a dma_fence_array
|
|
*
|
|
* Returns NULL if the fence is not a dma_fence_array,
|
|
* or the dma_fence_array otherwise.
|
|
*/
|
|
static inline struct dma_fence_array *
|
|
to_dma_fence_array(struct dma_fence *fence)
|
|
{
|
|
if (fence->ops != &dma_fence_array_ops)
|
|
return NULL;
|
|
|
|
return container_of(fence, struct dma_fence_array, base);
|
|
}
|
|
|
|
struct dma_fence_array *dma_fence_array_create(int num_fences,
|
|
struct dma_fence **fences,
|
|
u64 context, unsigned seqno,
|
|
bool signal_on_any);
|
|
|
|
bool dma_fence_match_context(struct dma_fence *fence, u64 context);
|
|
|
|
#endif /* __LINUX_DMA_FENCE_ARRAY_H */
|