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authorSebastian Ott <sebott@linux.vnet.ibm.com>2017-09-06 10:44:23 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2017-09-28 07:29:42 +0200
commit81b050b564b814585e1515b218783c8ad56913f1 (patch)
tree66087098513788356b2f24b03c0ea66120486e49
parent60f3eac3a1dc127541817af8042b6711e63dc6e1 (diff)
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: Sebastian Ott <sebott@linux.vnet.ibm.com> Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--drivers/s390/cio/cmf.c20
1 files changed, 3 insertions, 17 deletions
diff --git a/drivers/s390/cio/cmf.c b/drivers/s390/cio/cmf.c
index 7ed6c865501b..531861d005fd 100644
--- a/drivers/s390/cio/cmf.c
+++ b/drivers/s390/cio/cmf.c
@@ -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));
+ memcpy(cmb_data->last_block, hw_block, cmb_data->size);
cmb_data->last_update = get_tod_clock();
- kfree(reference_buf);
return 0;
}