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[S390] cio: obtain mdc value per channel path

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Add support to accumulate the number of 64K-bytes blocks all paths
to a device at least support for a transport command.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Sebastian Ott
2011-01-05 12:47:56 +01:00
committed by Martin Schwidefsky
parent 37e8952174
commit ce322ccd53
4 changed files with 79 additions and 0 deletions
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40
drivers/s390/cio/device_ops.c
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@@ -686,6 +686,46 @@ int ccw_device_tm_start_timeout(struct ccw_device *cdev, struct tcw *tcw,
}
EXPORT_SYMBOL(ccw_device_tm_start_timeout);
/**
* ccw_device_get_mdc - accumulate max data count
* @cdev: ccw device for which the max data count is accumulated
* @mask: mask of paths to use
*
* Return the number of 64K-bytes blocks all paths at least support
* for a transport command. Return values <= 0 indicate failures.
*/
int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask)
{
struct subchannel *sch = to_subchannel(cdev->dev.parent);
struct channel_path_desc_fmt1 desc;
struct chp_id chpid;
int mdc = 0, ret, i;
/* Adjust requested path mask to excluded varied off paths. */
if (mask)
mask &= sch->lpm;
else
mask = sch->lpm;
chp_id_init(&chpid);
for (i = 0; i < 8; i++) {
if (!(mask & (0x80 >> i)))
continue;
chpid.id = sch->schib.pmcw.chpid[i];
ret = chsc_determine_fmt1_channel_path_desc(chpid, &desc);
if (ret)
return ret;
if (!desc.f)
return 0;
if (!desc.r)
mdc = 1;
mdc = mdc ? min(mdc, (int)desc.mdc) : desc.mdc;
}
return mdc;
}
EXPORT_SYMBOL(ccw_device_get_mdc);
/**
* ccw_device_tm_intrg - perform interrogate function
* @cdev: ccw device on which to perform the interrogate function