Thanks for catching this Santosh. Have fixed this in v2 version of this patch
-- Cheers ~ Vaibhav Santosh Sivaraj <sant...@fossix.org> writes: > Hi Vaibhav, > > Vaibhav Jain <vaib...@linux.ibm.com> writes: > >> Persistent memory devices like NVDIMMs can loose cached writes in case >> something prevents flush on power-fail. Such situations are termed as >> dirty shutdown and are exposed to applications as >> last-shutdown-state (LSS) flag and a dirty-shutdown-counter(DSC) as >> described at [1]. The latter being useful in conditions where multiple >> applications want to detect a dirty shutdown event without racing with >> one another. >> >> PAPR-NVDIMMs have so far only exposed LSS style flags to indicate a >> dirty-shutdown-state. This patch further adds support for DSC via the >> "ibm,persistence-failed-count" device tree property of an NVDIMM. This >> property is a monotonic increasing 64-bit counter thats an indication >> of number of times an NVDIMM has encountered a dirty-shutdown event >> causing persistence loss. >> >> Since this value is not expected to change after system-boot hence >> papr_scm reads & caches its value during NVDIMM probe and exposes it >> as a PAPR sysfs attributed named 'dirty_shutdown' to match the name of >> similarly named NFIT sysfs attribute. Also this value is available to >> libnvdimm via PAPR_PDSM_HEALTH payload. 'struct nd_papr_pdsm_health' >> has been extended to add a new member called 'dimm_dsc' presence of >> which is indicated by the newly introduced PDSM_DIMM_DSC_VALID flag. >> >> References: >> [1] https://pmem.io/documents/Dirty_Shutdown_Handling-V1.0.pdf >> >> Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com> >> --- >> arch/powerpc/include/uapi/asm/papr_pdsm.h | 6 +++++ >> arch/powerpc/platforms/pseries/papr_scm.c | 30 +++++++++++++++++++++++ >> 2 files changed, 36 insertions(+) >> >> diff --git a/arch/powerpc/include/uapi/asm/papr_pdsm.h >> b/arch/powerpc/include/uapi/asm/papr_pdsm.h >> index 50ef95e2f5b1..82488b1e7276 100644 >> --- a/arch/powerpc/include/uapi/asm/papr_pdsm.h >> +++ b/arch/powerpc/include/uapi/asm/papr_pdsm.h >> @@ -77,6 +77,9 @@ >> /* Indicate that the 'dimm_fuel_gauge' field is valid */ >> #define PDSM_DIMM_HEALTH_RUN_GAUGE_VALID 1 >> >> +/* Indicate that the 'dimm_dsc' field is valid */ >> +#define PDSM_DIMM_DSC_VALID 2 >> + >> /* >> * Struct exchanged between kernel & ndctl in for PAPR_PDSM_HEALTH >> * Various flags indicate the health status of the dimm. >> @@ -105,6 +108,9 @@ struct nd_papr_pdsm_health { >> >> /* Extension flag PDSM_DIMM_HEALTH_RUN_GAUGE_VALID */ >> __u16 dimm_fuel_gauge; >> + >> + /* Extension flag PDSM_DIMM_DSC_VALID */ >> + __u64 dimm_dsc; >> }; >> __u8 buf[ND_PDSM_PAYLOAD_MAX_SIZE]; >> }; >> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c >> b/arch/powerpc/platforms/pseries/papr_scm.c >> index 11e7b90a3360..68f0d3d5e899 100644 >> --- a/arch/powerpc/platforms/pseries/papr_scm.c >> +++ b/arch/powerpc/platforms/pseries/papr_scm.c >> @@ -114,6 +114,9 @@ struct papr_scm_priv { >> /* Health information for the dimm */ >> u64 health_bitmap; >> >> + /* Holds the last known dirty shutdown counter value */ >> + u64 dirty_shutdown_counter; >> + >> /* length of the stat buffer as expected by phyp */ >> size_t stat_buffer_len; >> }; >> @@ -603,6 +606,16 @@ static int papr_pdsm_fuel_gauge(struct papr_scm_priv *p, >> return rc; >> } >> >> +/* Add the dirty-shutdown-counter value to the pdsm */ >> +static int papr_psdm_dsc(struct papr_scm_priv *p, > ^^^^ should be pdsm >> + union nd_pdsm_payload *payload) >> +{ >> + payload->health.extension_flags |= PDSM_DIMM_DSC_VALID; >> + payload->health.dimm_dsc = p->dirty_shutdown_counter; >> + >> + return sizeof(struct nd_papr_pdsm_health); >> +} >> + >> /* Fetch the DIMM health info and populate it in provided package. */ >> static int papr_pdsm_health(struct papr_scm_priv *p, >> union nd_pdsm_payload *payload) >> @@ -646,6 +659,8 @@ static int papr_pdsm_health(struct papr_scm_priv *p, >> >> /* Populate the fuel gauge meter in the payload */ >> papr_pdsm_fuel_gauge(p, payload); >> + /* Populate the dirty-shutdown-counter field */ >> + papr_psdm_dsc(p, payload); > ^^^^ same typo > > Thanks, > Santosh > >> >> rc = sizeof(struct nd_papr_pdsm_health); >> >> @@ -907,6 +922,16 @@ static ssize_t flags_show(struct device *dev, >> } >> DEVICE_ATTR_RO(flags); >> >> +static ssize_t dirty_shutdown_show(struct device *dev, >> + struct device_attribute *attr, char *buf) >> +{ >> + struct nvdimm *dimm = to_nvdimm(dev); >> + struct papr_scm_priv *p = nvdimm_provider_data(dimm); >> + >> + return sysfs_emit(buf, "%llu\n", p->dirty_shutdown_counter); >> +} >> +DEVICE_ATTR_RO(dirty_shutdown); >> + >> static umode_t papr_nd_attribute_visible(struct kobject *kobj, >> struct attribute *attr, int n) >> { >> @@ -925,6 +950,7 @@ static umode_t papr_nd_attribute_visible(struct kobject >> *kobj, >> static struct attribute *papr_nd_attributes[] = { >> &dev_attr_flags.attr, >> &dev_attr_perf_stats.attr, >> + &dev_attr_dirty_shutdown.attr, >> NULL, >> }; >> >> @@ -1149,6 +1175,10 @@ static int papr_scm_probe(struct platform_device >> *pdev) >> p->is_volatile = !of_property_read_bool(dn, "ibm,cache-flush-required"); >> p->hcall_flush_required = of_property_read_bool(dn, >> "ibm,hcall-flush-required"); >> >> + if (of_property_read_u64(dn, "ibm,persistence-failed-count", >> + &p->dirty_shutdown_counter)) >> + p->dirty_shutdown_counter = 0; >> + >> /* We just need to ensure that set cookies are unique across */ >> uuid_parse(uuid_str, (uuid_t *) uuid); >> /* >> -- >> 2.31.1 >
