Re: [PATCH 2/3] dma-buf: nuke DMA_FENCE_TRACE macros

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 29.07.21 um 09:22 schrieb Daniel Vetter:
> On Thu, Jul 29, 2021 at 09:03:29AM +0200, Christian König wrote:
>> Only the DRM GPU scheduler, radeon and amdgpu where using them and they depend
>> on a non existing config option to actually emit some code.
>>
>> Nuke them and clean up the dma_fence_signal* return value.
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
> So i915 is very much become a horror show of wheel reinventing (and we're
> trying to fix that), but there's some legit hand-rolled use-cases for
> having the return value of dma_fence_signal. We're not using that right
> now because hand-rollled nonsense, but can you perhaps keep that part?

I was considering that for the unit tests as well, but then though "nah, 
not if no drivers uses it".

But can I make that a bool while at it? E.g. true for was signaled and 
false for already signaled like we have for the callbacks?

Thanks,
Christian.

>
> Other pieces lgtm.
> -Daniel
>
>> ---
>>   drivers/dma-buf/dma-fence.c               | 44 +++++------------------
>>   drivers/dma-buf/st-dma-fence.c            | 12 ++-----
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 10 +-----
>>   drivers/gpu/drm/radeon/radeon_fence.c     | 24 +++----------
>>   drivers/gpu/drm/scheduler/sched_fence.c   | 18 ++--------
>>   include/linux/dma-fence.h                 | 32 +++--------------
>>   6 files changed, 23 insertions(+), 117 deletions(-)
>>
>> diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
>> index ce0f5eff575d..21cba0f74e69 100644
>> --- a/drivers/dma-buf/dma-fence.c
>> +++ b/drivers/dma-buf/dma-fence.c
>> @@ -350,12 +350,9 @@ void __dma_fence_might_wait(void)
>>    *
>>    * Unlike dma_fence_signal_timestamp(), this function must be called with
>>    * &dma_fence.lock held.
>> - *
>> - * Returns 0 on success and a negative error value when @fence has been
>> - * signalled already.
>>    */
>> -int dma_fence_signal_timestamp_locked(struct dma_fence *fence,
>> -				      ktime_t timestamp)
>> +void dma_fence_signal_timestamp_locked(struct dma_fence *fence,
>> +				       ktime_t timestamp)
>>   {
>>   	struct dma_fence_cb *cur, *tmp;
>>   	struct list_head cb_list;
>> @@ -364,7 +361,7 @@ int dma_fence_signal_timestamp_locked(struct dma_fence *fence,
>>   
>>   	if (unlikely(test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
>>   				      &fence->flags)))
>> -		return -EINVAL;
>> +		return;
>>   
>>   	/* Stash the cb_list before replacing it with the timestamp */
>>   	list_replace(&fence->cb_list, &cb_list);
>> @@ -377,8 +374,6 @@ int dma_fence_signal_timestamp_locked(struct dma_fence *fence,
>>   		INIT_LIST_HEAD(&cur->node);
>>   		cur->func(fence, cur);
>>   	}
>> -
>> -	return 0;
>>   }
>>   EXPORT_SYMBOL(dma_fence_signal_timestamp_locked);
>>   
>> @@ -393,23 +388,14 @@ EXPORT_SYMBOL(dma_fence_signal_timestamp_locked);
>>    * can only go from the unsignaled to the signaled state and not back, it will
>>    * only be effective the first time. Set the timestamp provided as the fence
>>    * signal timestamp.
>> - *
>> - * Returns 0 on success and a negative error value when @fence has been
>> - * signalled already.
>>    */
>> -int dma_fence_signal_timestamp(struct dma_fence *fence, ktime_t timestamp)
>> +void dma_fence_signal_timestamp(struct dma_fence *fence, ktime_t timestamp)
>>   {
>>   	unsigned long flags;
>> -	int ret;
>> -
>> -	if (!fence)
>> -		return -EINVAL;
>>   
>>   	spin_lock_irqsave(fence->lock, flags);
>> -	ret = dma_fence_signal_timestamp_locked(fence, timestamp);
>> +	dma_fence_signal_timestamp_locked(fence, timestamp);
>>   	spin_unlock_irqrestore(fence->lock, flags);
>> -
>> -	return ret;
>>   }
>>   EXPORT_SYMBOL(dma_fence_signal_timestamp);
>>   
>> @@ -425,13 +411,10 @@ EXPORT_SYMBOL(dma_fence_signal_timestamp);
>>    *
>>    * Unlike dma_fence_signal(), this function must be called with &dma_fence.lock
>>    * held.
>> - *
>> - * Returns 0 on success and a negative error value when @fence has been
>> - * signalled already.
>>    */
>> -int dma_fence_signal_locked(struct dma_fence *fence)
>> +void dma_fence_signal_locked(struct dma_fence *fence)
>>   {
>> -	return dma_fence_signal_timestamp_locked(fence, ktime_get());
>> +	dma_fence_signal_timestamp_locked(fence, ktime_get());
>>   }
>>   EXPORT_SYMBOL(dma_fence_signal_locked);
>>   
>> @@ -444,28 +427,19 @@ EXPORT_SYMBOL(dma_fence_signal_locked);
>>    * dma_fence_add_callback(). Can be called multiple times, but since a fence
>>    * can only go from the unsignaled to the signaled state and not back, it will
>>    * only be effective the first time.
>> - *
>> - * Returns 0 on success and a negative error value when @fence has been
>> - * signalled already.
>>    */
>> -int dma_fence_signal(struct dma_fence *fence)
>> +void dma_fence_signal(struct dma_fence *fence)
>>   {
>>   	unsigned long flags;
>> -	int ret;
>>   	bool tmp;
>>   
>> -	if (!fence)
>> -		return -EINVAL;
>> -
>>   	tmp = dma_fence_begin_signalling();
>>   
>>   	spin_lock_irqsave(fence->lock, flags);
>> -	ret = dma_fence_signal_timestamp_locked(fence, ktime_get());
>> +	dma_fence_signal_timestamp_locked(fence, ktime_get());
>>   	spin_unlock_irqrestore(fence->lock, flags);
>>   
>>   	dma_fence_end_signalling(tmp);
>> -
>> -	return ret;
>>   }
>>   EXPORT_SYMBOL(dma_fence_signal);
>>   
>> diff --git a/drivers/dma-buf/st-dma-fence.c b/drivers/dma-buf/st-dma-fence.c
>> index c8a12d7ad71a..e89001d8873f 100644
>> --- a/drivers/dma-buf/st-dma-fence.c
>> +++ b/drivers/dma-buf/st-dma-fence.c
>> @@ -122,21 +122,13 @@ static int test_signaling(void *arg)
>>   		goto err_free;
>>   	}
>>   
>> -	if (dma_fence_signal(f)) {
>> -		pr_err("Fence reported being already signaled\n");
>> -		goto err_free;
>> -	}
>> -
>> +	dma_fence_signal(f);
>>   	if (!dma_fence_is_signaled(f)) {
>>   		pr_err("Fence not reporting signaled\n");
>>   		goto err_free;
>>   	}
>>   
>> -	if (!dma_fence_signal(f)) {
>> -		pr_err("Fence reported not being already signaled\n");
>> -		goto err_free;
>> -	}
>> -
>> +	dma_fence_signal(f);
>>   	err = 0;
>>   err_free:
>>   	dma_fence_put(f);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>> index d4547d195173..397872779c31 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>> @@ -246,7 +246,6 @@ bool amdgpu_fence_process(struct amdgpu_ring *ring)
>>   	struct amdgpu_fence_driver *drv = &ring->fence_drv;
>>   	struct amdgpu_device *adev = ring->adev;
>>   	uint32_t seq, last_seq;
>> -	int r;
>>   
>>   	do {
>>   		last_seq = atomic_read(&ring->fence_drv.last_seq);
>> @@ -278,12 +277,7 @@ bool amdgpu_fence_process(struct amdgpu_ring *ring)
>>   		if (!fence)
>>   			continue;
>>   
>> -		r = dma_fence_signal(fence);
>> -		if (!r)
>> -			DMA_FENCE_TRACE(fence, "signaled from irq context\n");
>> -		else
>> -			BUG();
>> -
>> +		dma_fence_signal(fence);
>>   		dma_fence_put(fence);
>>   		pm_runtime_mark_last_busy(adev_to_drm(adev)->dev);
>>   		pm_runtime_put_autosuspend(adev_to_drm(adev)->dev);
>> @@ -673,8 +667,6 @@ static bool amdgpu_fence_enable_signaling(struct dma_fence *f)
>>   	if (!timer_pending(&ring->fence_drv.fallback_timer))
>>   		amdgpu_fence_schedule_fallback(ring);
>>   
>> -	DMA_FENCE_TRACE(&fence->base, "armed on ring %i!\n", ring->idx);
>> -
>>   	return true;
>>   }
>>   
>> diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
>> index 18f2c2e0dfb3..3f351d222cbb 100644
>> --- a/drivers/gpu/drm/radeon/radeon_fence.c
>> +++ b/drivers/gpu/drm/radeon/radeon_fence.c
>> @@ -176,18 +176,11 @@ static int radeon_fence_check_signaled(wait_queue_entry_t *wait, unsigned mode,
>>   	 */
>>   	seq = atomic64_read(&fence->rdev->fence_drv[fence->ring].last_seq);
>>   	if (seq >= fence->seq) {
>> -		int ret = dma_fence_signal_locked(&fence->base);
>> -
>> -		if (!ret)
>> -			DMA_FENCE_TRACE(&fence->base, "signaled from irq context\n");
>> -		else
>> -			DMA_FENCE_TRACE(&fence->base, "was already signaled\n");
>> -
>> +		dma_fence_signal_locked(&fence->base);
>>   		radeon_irq_kms_sw_irq_put(fence->rdev, fence->ring);
>>   		__remove_wait_queue(&fence->rdev->fence_queue, &fence->fence_wake);
>>   		dma_fence_put(&fence->base);
>> -	} else
>> -		DMA_FENCE_TRACE(&fence->base, "pending\n");
>> +	}
>>   	return 0;
>>   }
>>   
>> @@ -422,8 +415,6 @@ static bool radeon_fence_enable_signaling(struct dma_fence *f)
>>   	fence->fence_wake.func = radeon_fence_check_signaled;
>>   	__add_wait_queue(&rdev->fence_queue, &fence->fence_wake);
>>   	dma_fence_get(f);
>> -
>> -	DMA_FENCE_TRACE(&fence->base, "armed on ring %i!\n", fence->ring);
>>   	return true;
>>   }
>>   
>> @@ -441,11 +432,7 @@ bool radeon_fence_signaled(struct radeon_fence *fence)
>>   		return true;
>>   
>>   	if (radeon_fence_seq_signaled(fence->rdev, fence->seq, fence->ring)) {
>> -		int ret;
>> -
>> -		ret = dma_fence_signal(&fence->base);
>> -		if (!ret)
>> -			DMA_FENCE_TRACE(&fence->base, "signaled from radeon_fence_signaled\n");
>> +		dma_fence_signal(&fence->base);
>>   		return true;
>>   	}
>>   	return false;
>> @@ -550,7 +537,6 @@ long radeon_fence_wait_timeout(struct radeon_fence *fence, bool intr, long timeo
>>   {
>>   	uint64_t seq[RADEON_NUM_RINGS] = {};
>>   	long r;
>> -	int r_sig;
>>   
>>   	/*
>>   	 * This function should not be called on !radeon fences.
>> @@ -567,9 +553,7 @@ long radeon_fence_wait_timeout(struct radeon_fence *fence, bool intr, long timeo
>>   		return r;
>>   	}
>>   
>> -	r_sig = dma_fence_signal(&fence->base);
>> -	if (!r_sig)
>> -		DMA_FENCE_TRACE(&fence->base, "signaled from fence_wait\n");
>> +	dma_fence_signal(&fence->base);
>>   	return r;
>>   }
>>   
>> diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c
>> index 69de2c76731f..3736746c47bd 100644
>> --- a/drivers/gpu/drm/scheduler/sched_fence.c
>> +++ b/drivers/gpu/drm/scheduler/sched_fence.c
>> @@ -50,26 +50,12 @@ static void __exit drm_sched_fence_slab_fini(void)
>>   
>>   void drm_sched_fence_scheduled(struct drm_sched_fence *fence)
>>   {
>> -	int ret = dma_fence_signal(&fence->scheduled);
>> -
>> -	if (!ret)
>> -		DMA_FENCE_TRACE(&fence->scheduled,
>> -				"signaled from irq context\n");
>> -	else
>> -		DMA_FENCE_TRACE(&fence->scheduled,
>> -				"was already signaled\n");
>> +	dma_fence_signal(&fence->scheduled);
>>   }
>>   
>>   void drm_sched_fence_finished(struct drm_sched_fence *fence)
>>   {
>> -	int ret = dma_fence_signal(&fence->finished);
>> -
>> -	if (!ret)
>> -		DMA_FENCE_TRACE(&fence->finished,
>> -				"signaled from irq context\n");
>> -	else
>> -		DMA_FENCE_TRACE(&fence->finished,
>> -				"was already signaled\n");
>> +	dma_fence_signal(&fence->finished);
>>   }
>>   
>>   static const char *drm_sched_fence_get_driver_name(struct dma_fence *fence)
>> diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
>> index 6ffb4b2c6371..027db23fd4e3 100644
>> --- a/include/linux/dma-fence.h
>> +++ b/include/linux/dma-fence.h
>> @@ -370,11 +370,11 @@ static inline void dma_fence_end_signalling(bool cookie) {}
>>   static inline void __dma_fence_might_wait(void) {}
>>   #endif
>>   
>> -int dma_fence_signal(struct dma_fence *fence);
>> -int dma_fence_signal_locked(struct dma_fence *fence);
>> -int dma_fence_signal_timestamp(struct dma_fence *fence, ktime_t timestamp);
>> -int dma_fence_signal_timestamp_locked(struct dma_fence *fence,
>> -				      ktime_t timestamp);
>> +void dma_fence_signal(struct dma_fence *fence);
>> +void dma_fence_signal_locked(struct dma_fence *fence);
>> +void dma_fence_signal_timestamp(struct dma_fence *fence, ktime_t timestamp);
>> +void dma_fence_signal_timestamp_locked(struct dma_fence *fence,
>> +				       ktime_t timestamp);
>>   signed long dma_fence_default_wait(struct dma_fence *fence,
>>   				   bool intr, signed long timeout);
>>   int dma_fence_add_callback(struct dma_fence *fence,
>> @@ -590,26 +590,4 @@ struct dma_fence *dma_fence_get_stub(void);
>>   struct dma_fence *dma_fence_allocate_private_stub(void);
>>   u64 dma_fence_context_alloc(unsigned num);
>>   
>> -#define DMA_FENCE_TRACE(f, fmt, args...) \
>> -	do {								\
>> -		struct dma_fence *__ff = (f);				\
>> -		if (IS_ENABLED(CONFIG_DMA_FENCE_TRACE))			\
>> -			pr_info("f %llu#%llu: " fmt,			\
>> -				__ff->context, __ff->seqno, ##args);	\
>> -	} while (0)
>> -
>> -#define DMA_FENCE_WARN(f, fmt, args...) \
>> -	do {								\
>> -		struct dma_fence *__ff = (f);				\
>> -		pr_warn("f %llu#%llu: " fmt, __ff->context, __ff->seqno,\
>> -			 ##args);					\
>> -	} while (0)
>> -
>> -#define DMA_FENCE_ERR(f, fmt, args...) \
>> -	do {								\
>> -		struct dma_fence *__ff = (f);				\
>> -		pr_err("f %llu#%llu: " fmt, __ff->context, __ff->seqno,	\
>> -			##args);					\
>> -	} while (0)
>> -
>>   #endif /* __LINUX_DMA_FENCE_H */
>> -- 
>> 2.25.1
>>