Hi Ira, During v9 you had provided your ack to this patch [1] and also had made a review comment in a later patch regarding an avoidable 'goto' statement. I have since updated the patch addressing that review comment. Can you please provide your ack to this patch too.
[1] https://lore.kernel.org/linux-nvdimm/20200603231814.gk1505...@iweiny-desk2.sc.intel.com/T/#m668d7b35a2394104f11afdae5951e420a8ccffe6 [2] "I missed this... probably did not need the goto in the first patch?" https://lore.kernel.org/linux-nvdimm/20200603231814.gk1505...@iweiny-desk2.sc.intel.com/T/#m1ebdd309ac0cb6f47d3b574b8d05374b21ff75df Thanks, ~ Vaibhav Vaibhav Jain <vaib...@linux.ibm.com> writes: > Implement support for fetching nvdimm health information via > H_SCM_HEALTH hcall as documented in Ref[1]. The hcall returns a pair > of 64-bit bitmap, bitwise-and of which is then stored in > 'struct papr_scm_priv' and subsequently partially exposed to > user-space via newly introduced dimm specific attribute > 'papr/flags'. Since the hcall is costly, the health information is > cached and only re-queried, 60s after the previous successful hcall. > > The patch also adds a documentation text describing flags reported by > the the new sysfs attribute 'papr/flags' is also introduced at > Documentation/ABI/testing/sysfs-bus-papr-pmem. > > [1] commit 58b278f568f0 ("powerpc: Provide initial documentation for > PAPR hcalls") > > Cc: "Aneesh Kumar K . V" <aneesh.ku...@linux.ibm.com> > Cc: Dan Williams <dan.j.willi...@intel.com> > Cc: Michael Ellerman <m...@ellerman.id.au> > Cc: Ira Weiny <ira.we...@intel.com> > Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com> > --- > Changelog: > > v10..v11: > * None > > v9..v10: > * Removed an avoidable 'goto' in __drc_pmem_query_health. [ Ira ]. > > Resend: > * Added ack from Aneesh. > > v8..v9: > * Rename some variables and defines to reduce usage of term SCM > replacing it with PMEM [Dan Williams, Aneesh] > * s/PAPR_SCM_DIMM/PAPR_PMEM/g > * s/papr_scm_nd_attributes/papr_nd_attributes/g > * s/papr_scm_nd_attribute_group/papr_nd_attribute_group/g > * s/papr_scm_dimm_attr_groups/papr_nd_attribute_groups/g > * Renamed file sysfs-bus-papr-scm to sysfs-bus-papr-pmem > > v7..v8: > * Update type of variable 'rc' in __drc_pmem_query_health() and > drc_pmem_query_health() to long and int respectively. [ Ira ] > * Updated the patch description to s/64 bit Big Endian Number/64-bit > bitmap/ [ Ira, Aneesh ]. > > Resend: > * None > > v6..v7 : > * Used the exported buf_seq_printf() function to generate content for > 'papr/flags' > * Moved the PAPR_SCM_DIMM_* bit-flags macro definitions to papr_scm.c > and removed the papr_scm.h file [Mpe] > * Some minor consistency issued in sysfs-bus-papr-scm > documentation. [Mpe] > * s/dimm_mutex/health_mutex/g [Mpe] > * Split drc_pmem_query_health() into two function one of which takes > care of caching and locking. [Mpe] > * Fixed a local copy creation of dimm health information using > READ_ONCE(). [Mpe] > > v5..v6 : > * Change the flags sysfs attribute from 'papr_flags' to 'papr/flags' > [Dan Williams] > * Include documentation for 'papr/flags' attr [Dan Williams] > * Change flag 'save_fail' to 'flush_fail' [Dan Williams] > * Caching of health bitmap to reduce expensive hcalls [Dan Williams] > * Removed usage of PPC_BIT from 'papr-scm.h' header [Mpe] > * Replaced two __be64 integers from papr_scm_priv to a single u64 > integer [Mpe] > * Updated patch description to reflect the changes made in this > version. > * Removed avoidable usage of 'papr_scm_priv.dimm_mutex' from > flags_show() [Dan Williams] > > v4..v5 : > * None > > v3..v4 : > * None > > v2..v3 : > * Removed PAPR_SCM_DIMM_HEALTH_NON_CRITICAL as a condition for > NVDIMM unarmed [Aneesh] > > v1..v2 : > * New patch in the series. > --- > Documentation/ABI/testing/sysfs-bus-papr-pmem | 27 +++ > arch/powerpc/platforms/pseries/papr_scm.c | 168 +++++++++++++++++- > 2 files changed, 193 insertions(+), 2 deletions(-) > create mode 100644 Documentation/ABI/testing/sysfs-bus-papr-pmem > > diff --git a/Documentation/ABI/testing/sysfs-bus-papr-pmem > b/Documentation/ABI/testing/sysfs-bus-papr-pmem > new file mode 100644 > index 000000000000..5b10d036a8d4 > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-bus-papr-pmem > @@ -0,0 +1,27 @@ > +What: /sys/bus/nd/devices/nmemX/papr/flags > +Date: Apr, 2020 > +KernelVersion: v5.8 > +Contact: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>, > linux-nvd...@lists.01.org, > +Description: > + (RO) Report flags indicating various states of a > + papr-pmem NVDIMM device. Each flag maps to a one or > + more bits set in the dimm-health-bitmap retrieved in > + response to H_SCM_HEALTH hcall. The details of the bit > + flags returned in response to this hcall is available > + at 'Documentation/powerpc/papr_hcalls.rst' . Below are > + the flags reported in this sysfs file: > + > + * "not_armed" : Indicates that NVDIMM contents will not > + survive a power cycle. > + * "flush_fail" : Indicates that NVDIMM contents > + couldn't be flushed during last > + shut-down event. > + * "restore_fail": Indicates that NVDIMM contents > + couldn't be restored during NVDIMM > + initialization. > + * "encrypted" : NVDIMM contents are encrypted. > + * "smart_notify": There is health event for the NVDIMM. > + * "scrubbed" : Indicating that contents of the > + NVDIMM have been scrubbed. > + * "locked" : Indicating that NVDIMM contents cant > + be modified until next power cycle. > diff --git a/arch/powerpc/platforms/pseries/papr_scm.c > b/arch/powerpc/platforms/pseries/papr_scm.c > index f35592423380..0c091622b15e 100644 > --- a/arch/powerpc/platforms/pseries/papr_scm.c > +++ b/arch/powerpc/platforms/pseries/papr_scm.c > @@ -12,6 +12,7 @@ > #include <linux/libnvdimm.h> > #include <linux/platform_device.h> > #include <linux/delay.h> > +#include <linux/seq_buf.h> > > #include <asm/plpar_wrappers.h> > > @@ -22,6 +23,44 @@ > (1ul << ND_CMD_GET_CONFIG_DATA) | \ > (1ul << ND_CMD_SET_CONFIG_DATA)) > > +/* DIMM health bitmap bitmap indicators */ > +/* SCM device is unable to persist memory contents */ > +#define PAPR_PMEM_UNARMED (1ULL << (63 - 0)) > +/* SCM device failed to persist memory contents */ > +#define PAPR_PMEM_SHUTDOWN_DIRTY (1ULL << (63 - 1)) > +/* SCM device contents are persisted from previous IPL */ > +#define PAPR_PMEM_SHUTDOWN_CLEAN (1ULL << (63 - 2)) > +/* SCM device contents are not persisted from previous IPL */ > +#define PAPR_PMEM_EMPTY (1ULL << (63 - 3)) > +/* SCM device memory life remaining is critically low */ > +#define PAPR_PMEM_HEALTH_CRITICAL (1ULL << (63 - 4)) > +/* SCM device will be garded off next IPL due to failure */ > +#define PAPR_PMEM_HEALTH_FATAL (1ULL << (63 - 5)) > +/* SCM contents cannot persist due to current platform health status */ > +#define PAPR_PMEM_HEALTH_UNHEALTHY (1ULL << (63 - 6)) > +/* SCM device is unable to persist memory contents in certain conditions */ > +#define PAPR_PMEM_HEALTH_NON_CRITICAL (1ULL << (63 - 7)) > +/* SCM device is encrypted */ > +#define PAPR_PMEM_ENCRYPTED (1ULL << (63 - 8)) > +/* SCM device has been scrubbed and locked */ > +#define PAPR_PMEM_SCRUBBED_AND_LOCKED (1ULL << (63 - 9)) > + > +/* Bits status indicators for health bitmap indicating unarmed dimm */ > +#define PAPR_PMEM_UNARMED_MASK (PAPR_PMEM_UNARMED | \ > + PAPR_PMEM_HEALTH_UNHEALTHY) > + > +/* Bits status indicators for health bitmap indicating unflushed dimm */ > +#define PAPR_PMEM_BAD_SHUTDOWN_MASK (PAPR_PMEM_SHUTDOWN_DIRTY) > + > +/* Bits status indicators for health bitmap indicating unrestored dimm */ > +#define PAPR_PMEM_BAD_RESTORE_MASK (PAPR_PMEM_EMPTY) > + > +/* Bit status indicators for smart event notification */ > +#define PAPR_PMEM_SMART_EVENT_MASK (PAPR_PMEM_HEALTH_CRITICAL | \ > + PAPR_PMEM_HEALTH_FATAL | \ > + PAPR_PMEM_HEALTH_UNHEALTHY) > + > +/* private struct associated with each region */ > struct papr_scm_priv { > struct platform_device *pdev; > struct device_node *dn; > @@ -39,6 +78,15 @@ struct papr_scm_priv { > struct resource res; > struct nd_region *region; > struct nd_interleave_set nd_set; > + > + /* Protect dimm health data from concurrent read/writes */ > + struct mutex health_mutex; > + > + /* Last time the health information of the dimm was updated */ > + unsigned long lasthealth_jiffies; > + > + /* Health information for the dimm */ > + u64 health_bitmap; > }; > > static int drc_pmem_bind(struct papr_scm_priv *p) > @@ -144,6 +192,61 @@ static int drc_pmem_query_n_bind(struct papr_scm_priv *p) > return drc_pmem_bind(p); > } > > +/* > + * Issue hcall to retrieve dimm health info and populate papr_scm_priv with > the > + * health information. > + */ > +static int __drc_pmem_query_health(struct papr_scm_priv *p) > +{ > + unsigned long ret[PLPAR_HCALL_BUFSIZE]; > + long rc; > + > + /* issue the hcall */ > + rc = plpar_hcall(H_SCM_HEALTH, ret, p->drc_index); > + if (rc != H_SUCCESS) { > + dev_err(&p->pdev->dev, > + "Failed to query health information, Err:%ld\n", rc); > + return -ENXIO; > + } > + > + p->lasthealth_jiffies = jiffies; > + p->health_bitmap = ret[0] & ret[1]; > + > + dev_dbg(&p->pdev->dev, > + "Queried dimm health info. Bitmap:0x%016lx Mask:0x%016lx\n", > + ret[0], ret[1]); > + > + return 0; > +} > + > +/* Min interval in seconds for assuming stable dimm health */ > +#define MIN_HEALTH_QUERY_INTERVAL 60 > + > +/* Query cached health info and if needed call drc_pmem_query_health */ > +static int drc_pmem_query_health(struct papr_scm_priv *p) > +{ > + unsigned long cache_timeout; > + int rc; > + > + /* Protect concurrent modifications to papr_scm_priv */ > + rc = mutex_lock_interruptible(&p->health_mutex); > + if (rc) > + return rc; > + > + /* Jiffies offset for which the health data is assumed to be same */ > + cache_timeout = p->lasthealth_jiffies + > + msecs_to_jiffies(MIN_HEALTH_QUERY_INTERVAL * 1000); > + > + /* Fetch new health info is its older than MIN_HEALTH_QUERY_INTERVAL */ > + if (time_after(jiffies, cache_timeout)) > + rc = __drc_pmem_query_health(p); > + else > + /* Assume cached health data is valid */ > + rc = 0; > + > + mutex_unlock(&p->health_mutex); > + return rc; > +} > > static int papr_scm_meta_get(struct papr_scm_priv *p, > struct nd_cmd_get_config_data_hdr *hdr) > @@ -286,6 +389,64 @@ static int papr_scm_ndctl(struct nvdimm_bus_descriptor > *nd_desc, > return 0; > } > > +static ssize_t flags_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); > + struct seq_buf s; > + u64 health; > + int rc; > + > + rc = drc_pmem_query_health(p); > + if (rc) > + return rc; > + > + /* Copy health_bitmap locally, check masks & update out buffer */ > + health = READ_ONCE(p->health_bitmap); > + > + seq_buf_init(&s, buf, PAGE_SIZE); > + if (health & PAPR_PMEM_UNARMED_MASK) > + seq_buf_printf(&s, "not_armed "); > + > + if (health & PAPR_PMEM_BAD_SHUTDOWN_MASK) > + seq_buf_printf(&s, "flush_fail "); > + > + if (health & PAPR_PMEM_BAD_RESTORE_MASK) > + seq_buf_printf(&s, "restore_fail "); > + > + if (health & PAPR_PMEM_ENCRYPTED) > + seq_buf_printf(&s, "encrypted "); > + > + if (health & PAPR_PMEM_SMART_EVENT_MASK) > + seq_buf_printf(&s, "smart_notify "); > + > + if (health & PAPR_PMEM_SCRUBBED_AND_LOCKED) > + seq_buf_printf(&s, "scrubbed locked "); > + > + if (seq_buf_used(&s)) > + seq_buf_printf(&s, "\n"); > + > + return seq_buf_used(&s); > +} > +DEVICE_ATTR_RO(flags); > + > +/* papr_scm specific dimm attributes */ > +static struct attribute *papr_nd_attributes[] = { > + &dev_attr_flags.attr, > + NULL, > +}; > + > +static struct attribute_group papr_nd_attribute_group = { > + .name = "papr", > + .attrs = papr_nd_attributes, > +}; > + > +static const struct attribute_group *papr_nd_attr_groups[] = { > + &papr_nd_attribute_group, > + NULL, > +}; > + > static int papr_scm_nvdimm_init(struct papr_scm_priv *p) > { > struct device *dev = &p->pdev->dev; > @@ -312,8 +473,8 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p) > dimm_flags = 0; > set_bit(NDD_LABELING, &dimm_flags); > > - p->nvdimm = nvdimm_create(p->bus, p, NULL, dimm_flags, > - PAPR_SCM_DIMM_CMD_MASK, 0, NULL); > + p->nvdimm = nvdimm_create(p->bus, p, papr_nd_attr_groups, > + dimm_flags, PAPR_SCM_DIMM_CMD_MASK, 0, NULL); > if (!p->nvdimm) { > dev_err(dev, "Error creating DIMM object for %pOF\n", p->dn); > goto err; > @@ -399,6 +560,9 @@ static int papr_scm_probe(struct platform_device *pdev) > if (!p) > return -ENOMEM; > > + /* Initialize the dimm mutex */ > + mutex_init(&p->health_mutex); > + > /* optional DT properties */ > of_property_read_u32(dn, "ibm,metadata-size", &metadata_size); > > -- > 2.26.2 > -- Cheers ~ Vaibhav
