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

[Christian König <ckoenig.leichtzumerken@xxxxxxxxx>]

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@xxxxxxx>
> 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