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[S390] cio: introduce cio_update_schib

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There is the chance that we get condition code 0 for a stsch but
the resulting schib is not vaild. In the current code there are
2 cases:
* we do a check for validity of the schib after stsch, but at this
  time we have already stored the invaild schib in the subchannel
  structure. This may lead to problems.
* we don't do a check for validity, which is not that good either.

The patch addresses both issues by introducing the stsch wrapper
cio_update_schib which performs stsch on a local schib. This schib
is only written back to the subchannel if it's valid.

side note: For some functions (chp_events) the return codes are
different now (-ENXIO vs -ENODEV) but this shouldn't do harm
since the caller doesn't check for _specific_ errors.

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
2008-12-25 13:39:12 +01:00
committed by Martin Schwidefsky
parent d6a30761d8
commit cdb912a40d
8 changed files with 67 additions and 38 deletions
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8
drivers/s390/cio/cmf.c
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@@ -195,7 +195,8 @@ static int set_schib(struct ccw_device *cdev, u32 mme, int mbfc,
/* msch can silently fail, so do it again if necessary */
for (retry = 0; retry < 3; retry++) {
/* prepare schib */
stsch(sch->schid, schib);
if (cio_update_schib(sch))
return -ENODEV;
schib->pmcw.mme = mme;
schib->pmcw.mbfc = mbfc;
/* address can be either a block address or a block index */
@@ -219,7 +220,8 @@ static int set_schib(struct ccw_device *cdev, u32 mme, int mbfc,
ret = -EINVAL;
break;
}
stsch(sch->schid, schib); /* restore the schib */
if (cio_update_schib(sch))
return -ENODEV;
if (ret)
break;
@@ -338,7 +340,7 @@ static int cmf_copy_block(struct ccw_device *cdev)
sch = to_subchannel(cdev->dev.parent);
if (stsch(sch->schid, &sch->schib))
if (cio_update_schib(sch))
return -ENODEV;
if (scsw_fctl(&sch->schib.scsw) & SCSW_FCTL_START_FUNC) {