On 03.06.19 15:34, Cornelia Huck wrote:

On Mon, 3 Jun 2019 14:57:30 +0200
Halil Pasic [off-list ref] wrote:

quoted

On Mon, 3 Jun 2019 14:09:02 +0200
Michael Mueller [off-list ref] wrote:

quoted

quoted

quoted

@@ -224,6 +226,8 @@ struct subchannel *css_alloc_subchannel(struct subchannel_id schid,
   	INIT_WORK(&sch->todo_work, css_sch_todo);
   	sch->dev.release = &css_subchannel_release;
   	device_initialize(&sch->dev);

It might be helpful to add a comment why you use 31 bit here...

@Halil, please let me know what comment you prefere here...
   

How about?

/*
  * The physical addresses of some the dma structures that
  * can belong  to a subchannel need to fit 31 bit width (examples ccw,).
  */

"e.g. ccw"?

quoted

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+	sch->dev.coherent_dma_mask = DMA_BIT_MASK(31);
+	sch->dev.dma_mask = &sch->dev.coherent_dma_mask;
   	return sch;
   
   err:

@@ -899,6 +903,8 @@ static int __init setup_css(int nr)
   	dev_set_name(&css->device, "css%x", nr);
   	css->device.groups = cssdev_attr_groups;
   	css->device.release = channel_subsystem_release;

...and 64 bit here.

and here.

/*
  * We currently allocate notifier bits with this (using css->device
  * as the device argument with the DMA API), and are fine with 64 bit
  * addresses.
  */

Thanks, that makes things hopefully clearer if we look at it some time
in the future ;)

Applied both with with requested change.

Michael