From cdb912a40df8b8507ab60b3d52f9980c0ba1f44d Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Thu, 25 Dec 2008 13:39:12 +0100 Subject: [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 Signed-off-by: Martin Schwidefsky --- drivers/s390/cio/cio.c | 47 +++++++++++++++++++++++++++++++++++------------ 1 file changed, 35 insertions(+), 12 deletions(-) (limited to 'drivers/s390/cio/cio.c') diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c index 8047800e9a0c..9bdb463765c7 100644 --- a/drivers/s390/cio/cio.c +++ b/drivers/s390/cio/cio.c @@ -114,11 +114,13 @@ cio_start_handle_notoper(struct subchannel *sch, __u8 lpm) else sch->lpm = 0; - stsch (sch->schid, &sch->schib); - CIO_MSG_EVENT(2, "cio_start: 'not oper' status for " "subchannel 0.%x.%04x!\n", sch->schid.ssid, sch->schid.sch_no); + + if (cio_update_schib(sch)) + return -ENODEV; + sprintf(dbf_text, "no%s", dev_name(&sch->dev)); CIO_TRACE_EVENT(0, dbf_text); CIO_HEX_EVENT(0, &sch->schib, sizeof (struct schib)); @@ -316,7 +318,8 @@ cio_cancel (struct subchannel *sch) switch (ccode) { case 0: /* success */ /* Update information in scsw. */ - stsch (sch->schid, &sch->schib); + if (cio_update_schib(sch)) + return -ENODEV; return 0; case 1: /* status pending */ return -EBUSY; @@ -357,6 +360,23 @@ cio_modify (struct subchannel *sch) return ret; } +/** + * cio_update_schib - Perform stsch and update schib if subchannel is valid. + * @sch: subchannel on which to perform stsch + * Return zero on success, -ENODEV otherwise. + */ +int cio_update_schib(struct subchannel *sch) +{ + struct schib schib; + + if (stsch(sch->schid, &schib) || !css_sch_is_valid(&schib)) + return -ENODEV; + + memcpy(&sch->schib, &schib, sizeof(schib)); + return 0; +} +EXPORT_SYMBOL_GPL(cio_update_schib); + /** * cio_enable_subchannel - enable a subchannel. * @sch: subchannel to be enabled @@ -365,7 +385,6 @@ cio_modify (struct subchannel *sch) int cio_enable_subchannel(struct subchannel *sch, u32 intparm) { char dbf_txt[15]; - int ccode; int retry; int ret; @@ -374,8 +393,7 @@ int cio_enable_subchannel(struct subchannel *sch, u32 intparm) if (sch_is_pseudo_sch(sch)) return -EINVAL; - ccode = stsch (sch->schid, &sch->schib); - if (ccode) + if (cio_update_schib(sch)) return -ENODEV; for (retry = 5, ret = 0; retry > 0; retry--) { @@ -392,7 +410,10 @@ int cio_enable_subchannel(struct subchannel *sch, u32 intparm) */ sch->schib.pmcw.csense = 0; if (ret == 0) { - stsch (sch->schid, &sch->schib); + if (cio_update_schib(sch)) { + ret = -ENODEV; + break; + } if (sch->schib.pmcw.ena) break; } @@ -415,7 +436,6 @@ EXPORT_SYMBOL_GPL(cio_enable_subchannel); int cio_disable_subchannel(struct subchannel *sch) { char dbf_txt[15]; - int ccode; int retry; int ret; @@ -424,8 +444,7 @@ int cio_disable_subchannel(struct subchannel *sch) if (sch_is_pseudo_sch(sch)) return 0; - ccode = stsch (sch->schid, &sch->schib); - if (ccode == 3) /* Not operational. */ + if (cio_update_schib(sch)) return -ENODEV; if (scsw_actl(&sch->schib.scsw) != 0) @@ -448,7 +467,10 @@ int cio_disable_subchannel(struct subchannel *sch) */ break; if (ret == 0) { - stsch (sch->schid, &sch->schib); + if (cio_update_schib(sch)) { + ret = -ENODEV; + break; + } if (!sch->schib.pmcw.ena) break; } @@ -851,7 +873,8 @@ __disable_subchannel_easy(struct subchannel_id schid, struct schib *schib) cc = msch(schid, schib); if (cc) return (cc==3?-ENODEV:-EBUSY); - stsch(schid, schib); + if (stsch(schid, schib) || !css_sch_is_valid(schib)) + return -ENODEV; if (!schib->pmcw.ena) return 0; } -- cgit v1.2.3