Re: [PATCH] staging: android: ion: Skip sync if not mapped

[Dan Carpenter]

On Tue, Apr 14, 2020 at 04:18:47PM +0200, Ørjan Eide wrote:
> @@ -238,6 +242,10 @@ static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment,
>  			      struct sg_table *table,
>  			      enum dma_data_direction direction)
>  {
> +	struct ion_dma_buf_attachment *a = attachment->priv;
> +
> +	a->mapped = false;

Possibly a stupid question but here we're not holding a lock.  Is
concurrency an issue?

> +
>  	dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);
>  }
>  
> @@ -297,6 +305,8 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
>  
>  	mutex_lock(&buffer->lock);
>  	list_for_each_entry(a, &buffer->attachments, list) {
> +		if (!a->mapped)
> +			continue;
>  		dma_sync_sg_for_cpu(a->dev, a->table->sgl, a->table->nents,
>  				    direction);
>  	}

regards,
dan carpenter