Re: [PATCH 01/11] dma-buf: make fence sequence numbers 64 bit

[zhoucm1 <zhoucm1@xxxxxxx>]

On 2018年11月28日 22:50, Christian König wrote:
> For a lot of use cases we need 64bit sequence numbers. Currently drivers
> overload the dma_fence structure to store the additional bits.
>
> Stop doing that and make the sequence number in the dma_fence always
> 64bit.
>
> For compatibility with hardware which can do only 32bit sequences the
> comparisons in __dma_fence_is_later still only takes the lower 32bits as
> significant.
Can't we compare 64bit variable directly?  Can we do it as below?

-static inline bool __dma_fence_is_later(u32 f1, u32 f2)
+static inline bool __dma_fence_is_later(u64 f1, u64 f2)
 {
-	return (int)(f1 - f2) > 0;
+	return (f1 > f2) ? true : false;

 }

-David

> Signed-off-by: Christian König <christian.koenig@xxxxxxx>
> ---
>   drivers/dma-buf/dma-fence.c            |  2 +-
>   drivers/dma-buf/sw_sync.c              |  2 +-
>   drivers/dma-buf/sync_file.c            |  4 ++--
>   drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c |  2 +-
>   drivers/gpu/drm/i915/i915_sw_fence.c   |  2 +-
>   drivers/gpu/drm/i915/intel_engine_cs.c |  2 +-
>   drivers/gpu/drm/vgem/vgem_fence.c      |  4 ++--
>   include/linux/dma-fence.h              | 14 +++++++-------
>   8 files changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> index 1551ca7df394..37e24b69e94b 100644
> --- a/drivers/dma-buf/dma-fence.c
> +++ b/drivers/dma-buf/dma-fence.c
> @@ -615,7 +615,7 @@ EXPORT_SYMBOL(dma_fence_wait_any_timeout);
>    */
>   void
>   dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
> -	       spinlock_t *lock, u64 context, unsigned seqno)
> +	       spinlock_t *lock, u64 context, u64 seqno)
>   {
>   	BUG_ON(!lock);
>   	BUG_ON(!ops || !ops->get_driver_name || !ops->get_timeline_name);
> diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
> index 53c1d6d36a64..32dcf7b4c935 100644
> --- a/drivers/dma-buf/sw_sync.c
> +++ b/drivers/dma-buf/sw_sync.c
> @@ -172,7 +172,7 @@ static bool timeline_fence_enable_signaling(struct dma_fence *fence)
>   static void timeline_fence_value_str(struct dma_fence *fence,
>   				    char *str, int size)
>   {
> -	snprintf(str, size, "%d", fence->seqno);
> +	snprintf(str, size, "%lld", fence->seqno);
>   }
>   
>   static void timeline_fence_timeline_value_str(struct dma_fence *fence,
> diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
> index 35dd06479867..4f6305ca52c8 100644
> --- a/drivers/dma-buf/sync_file.c
> +++ b/drivers/dma-buf/sync_file.c
> @@ -144,7 +144,7 @@ char *sync_file_get_name(struct sync_file *sync_file, char *buf, int len)
>   	} else {
>   		struct dma_fence *fence = sync_file->fence;
>   
> -		snprintf(buf, len, "%s-%s%llu-%d",
> +		snprintf(buf, len, "%s-%s%llu-%lld",
>   			 fence->ops->get_driver_name(fence),
>   			 fence->ops->get_timeline_name(fence),
>   			 fence->context,
> @@ -258,7 +258,7 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
>   
>   			i_b++;
>   		} else {
> -			if (pt_a->seqno - pt_b->seqno <= INT_MAX)
> +			if (__dma_fence_is_later(pt_a->seqno, pt_b->seqno))
>   				add_fence(fences, &i, pt_a);
>   			else
>   				add_fence(fences, &i, pt_b);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c
> index 12f2bf97611f..bfaf5c6323be 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sa.c
> @@ -388,7 +388,7 @@ void amdgpu_sa_bo_dump_debug_info(struct amdgpu_sa_manager *sa_manager,
>   			   soffset, eoffset, eoffset - soffset);
>   
>   		if (i->fence)
> -			seq_printf(m, " protected by 0x%08x on context %llu",
> +			seq_printf(m, " protected by 0x%016llx on context %llu",
>   				   i->fence->seqno, i->fence->context);
>   
>   		seq_printf(m, "\n");
> diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
> index 6dbeed079ae5..11bcdabd5177 100644
> --- a/drivers/gpu/drm/i915/i915_sw_fence.c
> +++ b/drivers/gpu/drm/i915/i915_sw_fence.c
> @@ -393,7 +393,7 @@ static void timer_i915_sw_fence_wake(struct timer_list *t)
>   	if (!fence)
>   		return;
>   
> -	pr_notice("Asynchronous wait on fence %s:%s:%x timed out (hint:%pS)\n",
> +	pr_notice("Asynchronous wait on fence %s:%s:%llx timed out (hint:%pS)\n",
>   		  cb->dma->ops->get_driver_name(cb->dma),
>   		  cb->dma->ops->get_timeline_name(cb->dma),
>   		  cb->dma->seqno,
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index 217ed3ee1cab..f28a66c67d34 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -1236,7 +1236,7 @@ static void print_request(struct drm_printer *m,
>   
>   	x = print_sched_attr(rq->i915, &rq->sched.attr, buf, x, sizeof(buf));
>   
> -	drm_printf(m, "%s%x%s [%llx:%x]%s @ %dms: %s\n",
> +	drm_printf(m, "%s%x%s [%llx:%llx]%s @ %dms: %s\n",
>   		   prefix,
>   		   rq->global_seqno,
>   		   i915_request_completed(rq) ? "!" : "",
> diff --git a/drivers/gpu/drm/vgem/vgem_fence.c b/drivers/gpu/drm/vgem/vgem_fence.c
> index c1c420afe2dd..eb17c0cd3727 100644
> --- a/drivers/gpu/drm/vgem/vgem_fence.c
> +++ b/drivers/gpu/drm/vgem/vgem_fence.c
> @@ -53,13 +53,13 @@ static void vgem_fence_release(struct dma_fence *base)
>   
>   static void vgem_fence_value_str(struct dma_fence *fence, char *str, int size)
>   {
> -	snprintf(str, size, "%u", fence->seqno);
> +	snprintf(str, size, "%llu", fence->seqno);
>   }
>   
>   static void vgem_fence_timeline_value_str(struct dma_fence *fence, char *str,
>   					  int size)
>   {
> -	snprintf(str, size, "%u",
> +	snprintf(str, size, "%llu",
>   		 dma_fence_is_signaled(fence) ? fence->seqno : 0);
>   }
>   
> diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
> index 02dba8cd033d..1393529c0c1f 100644
> --- a/include/linux/dma-fence.h
> +++ b/include/linux/dma-fence.h
> @@ -77,7 +77,7 @@ struct dma_fence {
>   	struct list_head cb_list;
>   	spinlock_t *lock;
>   	u64 context;
> -	unsigned seqno;
> +	u64 seqno;
>   	unsigned long flags;
>   	ktime_t timestamp;
>   	int error;
> @@ -244,7 +244,7 @@ struct dma_fence_ops {
>   };
>   
>   void dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
> -		    spinlock_t *lock, u64 context, unsigned seqno);
> +		    spinlock_t *lock, u64 context, u64 seqno);
>   
>   void dma_fence_release(struct kref *kref);
>   void dma_fence_free(struct dma_fence *fence);
> @@ -414,9 +414,9 @@ dma_fence_is_signaled(struct dma_fence *fence)
>    * Returns true if f1 is chronologically later than f2. Both fences must be
>    * from the same context, since a seqno is not common across contexts.
>    */
> -static inline bool __dma_fence_is_later(u32 f1, u32 f2)
> +static inline bool __dma_fence_is_later(u64 f1, u64 f2)
>   {
> -	return (int)(f1 - f2) > 0;
> +	return (int)(lower_32_bits(f1) - lower_32_bits(f2)) > 0;
>   }
>   
>   /**
> @@ -547,21 +547,21 @@ u64 dma_fence_context_alloc(unsigned num);
>   	do {								\
>   		struct dma_fence *__ff = (f);				\
>   		if (IS_ENABLED(CONFIG_DMA_FENCE_TRACE))			\
> -			pr_info("f %llu#%u: " fmt,			\
> +			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#%u: " fmt, __ff->context, __ff->seqno,	\
> +		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#%u: " fmt, __ff->context, __ff->seqno,	\
> +		pr_err("f %llu#%llu: " fmt, __ff->context, __ff->seqno,	\
>   			##args);					\
>   	} while (0)
>   

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