mirror of
https://github.com/torvalds/linux.git
synced 2024-12-07 03:21:32 +00:00
dma-buf: add new dma_fence_chain container v7
Lockless container implementation similar to a dma_fence_array, but with only two elements per node and automatic garbage collection. v2: properly document dma_fence_chain_for_each, add dma_fence_chain_find_seqno, drop prev reference during garbage collection if it's not a chain fence. v3: use head and iterator for dma_fence_chain_for_each v4: fix reference count in dma_fence_chain_enable_signaling v5: fix iteration when walking each chain node v6: add __rcu for member 'prev' of struct chain node v7: fix rcu warnings from kernel robot Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Link: https://patchwork.freedesktop.org/patch/295778/?series=58813&rev=1
This commit is contained in:
parent
64e1f830ea
commit
7bf60c52e0
@ -1,4 +1,5 @@
|
||||
obj-y := dma-buf.o dma-fence.o dma-fence-array.o reservation.o seqno-fence.o
|
||||
obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
|
||||
reservation.o seqno-fence.o
|
||||
obj-$(CONFIG_SYNC_FILE) += sync_file.o
|
||||
obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
|
||||
obj-$(CONFIG_UDMABUF) += udmabuf.o
|
||||
|
241
drivers/dma-buf/dma-fence-chain.c
Normal file
241
drivers/dma-buf/dma-fence-chain.c
Normal file
@ -0,0 +1,241 @@
|
||||
/*
|
||||
* fence-chain: chain fences together in a timeline
|
||||
*
|
||||
* Copyright (C) 2018 Advanced Micro Devices, Inc.
|
||||
* Authors:
|
||||
* 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.
|
||||
*/
|
||||
|
||||
#include <linux/dma-fence-chain.h>
|
||||
|
||||
static bool dma_fence_chain_enable_signaling(struct dma_fence *fence);
|
||||
|
||||
/**
|
||||
* dma_fence_chain_get_prev - use RCU to get a reference to the previous fence
|
||||
* @chain: chain node to get the previous node from
|
||||
*
|
||||
* Use dma_fence_get_rcu_safe to get a reference to the previous fence of the
|
||||
* chain node.
|
||||
*/
|
||||
static struct dma_fence *dma_fence_chain_get_prev(struct dma_fence_chain *chain)
|
||||
{
|
||||
struct dma_fence *prev;
|
||||
|
||||
rcu_read_lock();
|
||||
prev = dma_fence_get_rcu_safe(&chain->prev);
|
||||
rcu_read_unlock();
|
||||
return prev;
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_fence_chain_walk - chain walking function
|
||||
* @fence: current chain node
|
||||
*
|
||||
* Walk the chain to the next node. Returns the next fence or NULL if we are at
|
||||
* the end of the chain. Garbage collects chain nodes which are already
|
||||
* signaled.
|
||||
*/
|
||||
struct dma_fence *dma_fence_chain_walk(struct dma_fence *fence)
|
||||
{
|
||||
struct dma_fence_chain *chain, *prev_chain;
|
||||
struct dma_fence *prev, *replacement, *tmp;
|
||||
|
||||
chain = to_dma_fence_chain(fence);
|
||||
if (!chain) {
|
||||
dma_fence_put(fence);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
while ((prev = dma_fence_chain_get_prev(chain))) {
|
||||
|
||||
prev_chain = to_dma_fence_chain(prev);
|
||||
if (prev_chain) {
|
||||
if (!dma_fence_is_signaled(prev_chain->fence))
|
||||
break;
|
||||
|
||||
replacement = dma_fence_chain_get_prev(prev_chain);
|
||||
} else {
|
||||
if (!dma_fence_is_signaled(prev))
|
||||
break;
|
||||
|
||||
replacement = NULL;
|
||||
}
|
||||
|
||||
tmp = cmpxchg((void **)&chain->prev, (void *)prev, (void *)replacement);
|
||||
if (tmp == prev)
|
||||
dma_fence_put(tmp);
|
||||
else
|
||||
dma_fence_put(replacement);
|
||||
dma_fence_put(prev);
|
||||
}
|
||||
|
||||
dma_fence_put(fence);
|
||||
return prev;
|
||||
}
|
||||
EXPORT_SYMBOL(dma_fence_chain_walk);
|
||||
|
||||
/**
|
||||
* dma_fence_chain_find_seqno - find fence chain node by seqno
|
||||
* @pfence: pointer to the chain node where to start
|
||||
* @seqno: the sequence number to search for
|
||||
*
|
||||
* Advance the fence pointer to the chain node which will signal this sequence
|
||||
* number. If no sequence number is provided then this is a no-op.
|
||||
*
|
||||
* Returns EINVAL if the fence is not a chain node or the sequence number has
|
||||
* not yet advanced far enough.
|
||||
*/
|
||||
int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t seqno)
|
||||
{
|
||||
struct dma_fence_chain *chain;
|
||||
|
||||
if (!seqno)
|
||||
return 0;
|
||||
|
||||
chain = to_dma_fence_chain(*pfence);
|
||||
if (!chain || chain->base.seqno < seqno)
|
||||
return -EINVAL;
|
||||
|
||||
dma_fence_chain_for_each(*pfence, &chain->base) {
|
||||
if ((*pfence)->context != chain->base.context ||
|
||||
to_dma_fence_chain(*pfence)->prev_seqno < seqno)
|
||||
break;
|
||||
}
|
||||
dma_fence_put(&chain->base);
|
||||
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL(dma_fence_chain_find_seqno);
|
||||
|
||||
static const char *dma_fence_chain_get_driver_name(struct dma_fence *fence)
|
||||
{
|
||||
return "dma_fence_chain";
|
||||
}
|
||||
|
||||
static const char *dma_fence_chain_get_timeline_name(struct dma_fence *fence)
|
||||
{
|
||||
return "unbound";
|
||||
}
|
||||
|
||||
static void dma_fence_chain_irq_work(struct irq_work *work)
|
||||
{
|
||||
struct dma_fence_chain *chain;
|
||||
|
||||
chain = container_of(work, typeof(*chain), work);
|
||||
|
||||
/* Try to rearm the callback */
|
||||
if (!dma_fence_chain_enable_signaling(&chain->base))
|
||||
/* Ok, we are done. No more unsignaled fences left */
|
||||
dma_fence_signal(&chain->base);
|
||||
dma_fence_put(&chain->base);
|
||||
}
|
||||
|
||||
static void dma_fence_chain_cb(struct dma_fence *f, struct dma_fence_cb *cb)
|
||||
{
|
||||
struct dma_fence_chain *chain;
|
||||
|
||||
chain = container_of(cb, typeof(*chain), cb);
|
||||
irq_work_queue(&chain->work);
|
||||
dma_fence_put(f);
|
||||
}
|
||||
|
||||
static bool dma_fence_chain_enable_signaling(struct dma_fence *fence)
|
||||
{
|
||||
struct dma_fence_chain *head = to_dma_fence_chain(fence);
|
||||
|
||||
dma_fence_get(&head->base);
|
||||
dma_fence_chain_for_each(fence, &head->base) {
|
||||
struct dma_fence_chain *chain = to_dma_fence_chain(fence);
|
||||
struct dma_fence *f = chain ? chain->fence : fence;
|
||||
|
||||
dma_fence_get(f);
|
||||
if (!dma_fence_add_callback(f, &head->cb, dma_fence_chain_cb)) {
|
||||
dma_fence_put(fence);
|
||||
return true;
|
||||
}
|
||||
dma_fence_put(f);
|
||||
}
|
||||
dma_fence_put(&head->base);
|
||||
return false;
|
||||
}
|
||||
|
||||
static bool dma_fence_chain_signaled(struct dma_fence *fence)
|
||||
{
|
||||
dma_fence_chain_for_each(fence, fence) {
|
||||
struct dma_fence_chain *chain = to_dma_fence_chain(fence);
|
||||
struct dma_fence *f = chain ? chain->fence : fence;
|
||||
|
||||
if (!dma_fence_is_signaled(f)) {
|
||||
dma_fence_put(fence);
|
||||
return false;
|
||||
}
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
static void dma_fence_chain_release(struct dma_fence *fence)
|
||||
{
|
||||
struct dma_fence_chain *chain = to_dma_fence_chain(fence);
|
||||
|
||||
dma_fence_put(rcu_dereference_protected(chain->prev, true));
|
||||
dma_fence_put(chain->fence);
|
||||
dma_fence_free(fence);
|
||||
}
|
||||
|
||||
const struct dma_fence_ops dma_fence_chain_ops = {
|
||||
.get_driver_name = dma_fence_chain_get_driver_name,
|
||||
.get_timeline_name = dma_fence_chain_get_timeline_name,
|
||||
.enable_signaling = dma_fence_chain_enable_signaling,
|
||||
.signaled = dma_fence_chain_signaled,
|
||||
.release = dma_fence_chain_release,
|
||||
};
|
||||
EXPORT_SYMBOL(dma_fence_chain_ops);
|
||||
|
||||
/**
|
||||
* dma_fence_chain_init - initialize a fence chain
|
||||
* @chain: the chain node to initialize
|
||||
* @prev: the previous fence
|
||||
* @fence: the current fence
|
||||
*
|
||||
* Initialize a new chain node and either start a new chain or add the node to
|
||||
* the existing chain of the previous fence.
|
||||
*/
|
||||
void dma_fence_chain_init(struct dma_fence_chain *chain,
|
||||
struct dma_fence *prev,
|
||||
struct dma_fence *fence,
|
||||
uint64_t seqno)
|
||||
{
|
||||
struct dma_fence_chain *prev_chain = to_dma_fence_chain(prev);
|
||||
uint64_t context;
|
||||
|
||||
spin_lock_init(&chain->lock);
|
||||
rcu_assign_pointer(chain->prev, prev);
|
||||
chain->fence = fence;
|
||||
chain->prev_seqno = 0;
|
||||
init_irq_work(&chain->work, dma_fence_chain_irq_work);
|
||||
|
||||
/* Try to reuse the context of the previous chain node. */
|
||||
if (prev_chain && __dma_fence_is_later(seqno, prev->seqno)) {
|
||||
context = prev->context;
|
||||
chain->prev_seqno = prev->seqno;
|
||||
} else {
|
||||
context = dma_fence_context_alloc(1);
|
||||
/* Make sure that we always have a valid sequence number. */
|
||||
if (prev_chain)
|
||||
seqno = max(prev->seqno, seqno);
|
||||
}
|
||||
|
||||
dma_fence_init(&chain->base, &dma_fence_chain_ops,
|
||||
&chain->lock, context, seqno);
|
||||
}
|
||||
EXPORT_SYMBOL(dma_fence_chain_init);
|
81
include/linux/dma-fence-chain.h
Normal file
81
include/linux/dma-fence-chain.h
Normal file
@ -0,0 +1,81 @@
|
||||
/*
|
||||
* fence-chain: chain fences together in a timeline
|
||||
*
|
||||
* Copyright (C) 2018 Advanced Micro Devices, Inc.
|
||||
* Authors:
|
||||
* 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_CHAIN_H
|
||||
#define __LINUX_DMA_FENCE_CHAIN_H
|
||||
|
||||
#include <linux/dma-fence.h>
|
||||
#include <linux/irq_work.h>
|
||||
|
||||
/**
|
||||
* struct dma_fence_chain - fence to represent an node of a fence chain
|
||||
* @base: fence base class
|
||||
* @lock: spinlock for fence handling
|
||||
* @prev: previous fence of the chain
|
||||
* @prev_seqno: original previous seqno before garbage collection
|
||||
* @fence: encapsulated fence
|
||||
* @cb: callback structure for signaling
|
||||
* @work: irq work item for signaling
|
||||
*/
|
||||
struct dma_fence_chain {
|
||||
struct dma_fence base;
|
||||
spinlock_t lock;
|
||||
struct dma_fence __rcu *prev;
|
||||
u64 prev_seqno;
|
||||
struct dma_fence *fence;
|
||||
struct dma_fence_cb cb;
|
||||
struct irq_work work;
|
||||
};
|
||||
|
||||
extern const struct dma_fence_ops dma_fence_chain_ops;
|
||||
|
||||
/**
|
||||
* to_dma_fence_chain - cast a fence to a dma_fence_chain
|
||||
* @fence: fence to cast to a dma_fence_array
|
||||
*
|
||||
* Returns NULL if the fence is not a dma_fence_chain,
|
||||
* or the dma_fence_chain otherwise.
|
||||
*/
|
||||
static inline struct dma_fence_chain *
|
||||
to_dma_fence_chain(struct dma_fence *fence)
|
||||
{
|
||||
if (!fence || fence->ops != &dma_fence_chain_ops)
|
||||
return NULL;
|
||||
|
||||
return container_of(fence, struct dma_fence_chain, base);
|
||||
}
|
||||
|
||||
/**
|
||||
* dma_fence_chain_for_each - iterate over all fences in chain
|
||||
* @iter: current fence
|
||||
* @head: starting point
|
||||
*
|
||||
* Iterate over all fences in the chain. We keep a reference to the current
|
||||
* fence while inside the loop which must be dropped when breaking out.
|
||||
*/
|
||||
#define dma_fence_chain_for_each(iter, head) \
|
||||
for (iter = dma_fence_get(head); iter; \
|
||||
iter = dma_fence_chain_walk(iter))
|
||||
|
||||
struct dma_fence *dma_fence_chain_walk(struct dma_fence *fence);
|
||||
int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t seqno);
|
||||
void dma_fence_chain_init(struct dma_fence_chain *chain,
|
||||
struct dma_fence *prev,
|
||||
struct dma_fence *fence,
|
||||
uint64_t seqno);
|
||||
|
||||
#endif /* __LINUX_DMA_FENCE_CHAIN_H */
|
Loading…
Reference in New Issue
Block a user