On 3/22/22 03:09, Dan Williams wrote:
> On Fri, Mar 18, 2022 at 4:42 AM Kajol Jain <kjain@xxxxxxxxxxxxx> wrote:
>>
>> The following build failure occures when CONFIG_PERF_EVENTS is not set
>> as generic pmu functions are not visible in that scenario.
>>
>> arch/powerpc/platforms/pseries/papr_scm.c:372:35: error: ‘struct perf_event’ has no member named ‘attr’
>> p->nvdimm_events_map[event->attr.config],
>> ^~
>> In file included from ./include/linux/list.h:5,
>> from ./include/linux/kobject.h:19,
>> from ./include/linux/of.h:17,
>> from arch/powerpc/platforms/pseries/papr_scm.c:5:
>> arch/powerpc/platforms/pseries/papr_scm.c: In function ‘papr_scm_pmu_event_init’:
>> arch/powerpc/platforms/pseries/papr_scm.c:389:49: error: ‘struct perf_event’ has no member named ‘pmu’
>> struct nvdimm_pmu *nd_pmu = to_nvdimm_pmu(event->pmu);
>> ^~
>> ./include/linux/container_of.h:18:26: note: in definition of macro ‘container_of’
>> void *__mptr = (void *)(ptr); \
>> ^~~
>> arch/powerpc/platforms/pseries/papr_scm.c:389:30: note: in expansion of macro ‘to_nvdimm_pmu’
>> struct nvdimm_pmu *nd_pmu = to_nvdimm_pmu(event->pmu);
>> ^~~~~~~~~~~~~
>> In file included from ./include/linux/bits.h:22,
>> from ./include/linux/bitops.h:6,
>> from ./include/linux/of.h:15,
>> from arch/powerpc/platforms/pseries/papr_scm.c:5:
>>
>> Fix the build issue by adding check for CONFIG_PERF_EVENTS config option
>> and disabling the papr_scm perf interface support incase this config
>> is not set
>>
>> Fixes: 4c08d4bbc089 ("powerpc/papr_scm: Add perf interface support") (Commit id
>> based on linux-next tree)
>> Signed-off-by: Kajol Jain <kjain@xxxxxxxxxxxxx>
>> ---
>> arch/powerpc/platforms/pseries/papr_scm.c | 15 +++++++++++++++
>
> This is a bit messier than I would have liked mainly because it dumps
> a bunch of ifdefery into a C file contrary to coding style, "Wherever
> possible, don't use preprocessor conditionals (#if, #ifdef) in .c
> files". I would expect this all to move to an organization like:
Hi Dan,
Thanks for reviewing the patches. Inorder to avoid the multiple
ifdefs checks, we can also add stub function for papr_scm_pmu_register.
With that change we will just have one ifdef check for
CONFIG_PERF_EVENTS config in both papr_scm.c and nd.h file. Hence we can
avoid adding new files specific for papr_scm perf interface.
Below is the code snippet for that change, let me know if looks fine to
you. I tested it
with set/unset PAPR_SCM config value and set/unset PERF_EVENTS config
value combinations.
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
b/arch/powerpc/platforms/pseries/papr_scm.c
index 4dd513d7c029..38fabb44d3c3 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -69,8 +69,6 @@
#define PAPR_SCM_PERF_STATS_EYECATCHER __stringify(SCMSTATS)
#define PAPR_SCM_PERF_STATS_VERSION 0x1
-#define to_nvdimm_pmu(_pmu) container_of(_pmu, struct nvdimm_pmu, pmu)
-
/* Struct holding a single performance metric */
struct papr_scm_perf_stat {
u8 stat_id[8];
@@ -346,6 +344,9 @@ static ssize_t drc_pmem_query_stats(struct
papr_scm_priv *p,
return 0;
}
+#ifdef CONFIG_PERF_EVENTS
+#define to_nvdimm_pmu(_pmu) container_of(_pmu, struct nvdimm_pmu, pmu)
+
static int papr_scm_pmu_get_value(struct perf_event *event, struct
device *dev, u64 *count)
{
struct papr_scm_perf_stat *stat;
@@ -558,6 +559,10 @@ static void papr_scm_pmu_register(struct
papr_scm_priv *p)
dev_info(&p->pdev->dev, "nvdimm pmu didn't register rc=%d\n", rc);
}
+#else
+static inline void papr_scm_pmu_register(struct papr_scm_priv *p) { }
+#endif
+
/*
* Issue hcall to retrieve dimm health info and populate papr_scm_priv
with the
* health information.
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
index 3fb806748716..ba0296dca9db 100644
--- a/drivers/nvdimm/Makefile
+++ b/drivers/nvdimm/Makefile
@@ -15,7 +15,7 @@ nd_e820-y := e820.o
libnvdimm-y := core.o
libnvdimm-y += bus.o
libnvdimm-y += dimm_devs.o
-libnvdimm-y += nd_perf.o
+libnvdimm-$(CONFIG_PERF_EVENTS) += nd_perf.o
libnvdimm-y += dimm.o
libnvdimm-y += region_devs.o
libnvdimm-y += region.o
diff --git a/include/linux/nd.h b/include/linux/nd.h
index 7b2ccbdc1cbc..a387e2b630ad 100644
--- a/include/linux/nd.h
+++ b/include/linux/nd.h
@@ -57,15 +57,22 @@ struct nvdimm_pmu {
struct cpumask arch_cpumask;
};
+#ifdef CONFIG_PERF_EVENTS
extern ssize_t nvdimm_events_sysfs_show(struct device *dev,
struct device_attribute *attr,
char *page);
int register_nvdimm_pmu(struct nvdimm_pmu *nvdimm, struct
platform_device *pdev);
void unregister_nvdimm_pmu(struct nvdimm_pmu *nd_pmu);
-void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu);
-int perf_pmu_register(struct pmu *pmu, const char *name, int type);
-void perf_pmu_unregister(struct pmu *pmu);
+
+#else
+static inline int register_nvdimm_pmu(struct nvdimm_pmu *nd_pmu, struct
platform_device *pdev)
+{
+ return -ENXIO;
+}
+
+static inline void unregister_nvdimm_pmu(struct nvdimm_pmu *nd_pmu) { }
+#endif
struct nd_device_driver {
struct device_driver drv;
>
> arch/powerpc/platforms/pseries/papr_scm/main.c
> arch/powerpc/platforms/pseries/papr_scm/perf.c
>
> ...and a new config symbol like:
>
> config PAPR_SCM_PERF
> depends on PAPR_SCM && PERF_EVENTS
> def_bool y
>
> ...with wrappers in header files to make everything compile away
> without any need for main.c to carry an ifdef.
>
> Can you turn a patch like that in the next couple days? Otherwise, I
> think if Linus saw me sending a late breaking compile fix that threw
> coding style out the window he'd have cause to just drop the pull
> request entirely.
Sure Dan, I will work on the patches and send it asap once we finalized
the changes.
Thanks,
Kajol Jain
