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| author |   Sebastian Ott <sebott@linux.vnet.ibm.com> | 2008-12-25 13:39:12 +0100 |
|---|---|---|
| committer |   Martin Schwidefsky <schwidefsky@de.ibm.com> | 2008-12-25 13:39:10 +0100 |
| commit | cdb912a40df8b8507ab60b3d52f9980c0ba1f44d (patch) | |
| tree | 52d693b3515b71b4f84b539d41571facb75498db /drivers/s390/cio/cmf.c | |
| parent | [S390] cio: Use device_is_registered(). (diff) | |
| download | linux-dev-cdb912a40df8b8507ab60b3d52f9980c0ba1f44d.tar.xz linux-dev-cdb912a40df8b8507ab60b3d52f9980c0ba1f44d.zip | |
[S390] cio: introduce cio_update_schib
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>
Diffstat (limited to 'drivers/s390/cio/cmf.c')
| -rw-r--r-- | drivers/s390/cio/cmf.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/s390/cio/cmf.c b/drivers/s390/cio/cmf.c index a90b28c0be57..288482b21048 100644 --- a/drivers/s390/cio/cmf.c +++ b/drivers/s390/cio/cmf.c @@ -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) { |