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Commit 81b050b5 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
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s390/cmf: simplify copy_block 



cmf_copy_block tries to ensure data consistency by copying the
channel measurement block twice and comparing the data. This was
needed on very old machines only. Nowadays we guarantee
consistency by copying the data when the channel is idle.

Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: default avatarPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 60f3eac3

drivers/s390/cio/cmf.c

+3 −17
Original line number Diff line number Diff line
@@ -280,12 +280,9 @@ void retry_set_schib(struct ccw_device *cdev) 


static int cmf_copy_block(struct ccw_device *cdev)

{

	struct subchannel *sch;

	void *reference_buf;

	void *hw_block;

	struct subchannel *sch = to_subchannel(cdev->dev.parent);

	struct cmb_data *cmb_data;



	sch = to_subchannel(cdev->dev.parent);

	void *hw_block;



	if (cio_update_schib(sch))

		return -ENODEV;
@@ -300,19 +297,8 @@ static int cmf_copy_block(struct ccw_device *cdev) 
	}

	cmb_data = cdev->private->cmb;

	hw_block = cmb_data->hw_block;

	if (!memcmp(cmb_data->last_block, hw_block, cmb_data->size))

		/* No need to copy. */

		return 0;

	reference_buf = kzalloc(cmb_data->size, GFP_ATOMIC);

	if (!reference_buf)

		return -ENOMEM;

	/* Ensure consistency of block copied from hardware. */

	do {

	memcpy(cmb_data->last_block, hw_block, cmb_data->size);

		memcpy(reference_buf, hw_block, cmb_data->size);

	} while (memcmp(cmb_data->last_block, reference_buf, cmb_data->size));

	cmb_data->last_update = get_tod_clock();

	kfree(reference_buf);

	return 0;

}