[v2 PATCH 1/2] drivers/nvdimm: Fix build failure when CONFIG_PERF_EVENTS is not set

[v2 PATCH 1/2] drivers/nvdimm: Fix build failure when CONFIG_PERF_EVENTS is not set

[Kajol Jain]

The following build failure occurs when CONFIG_PERF_EVENTS is not set
as generic pmu functions are not visible in that scenario.

|-- s390-randconfig-r044-20220313
|   |-- nd_perf.c:(.text):undefined-reference-to-perf_pmu_migrate_context
|   |-- nd_perf.c:(.text):undefined-reference-to-perf_pmu_register
|   `-- nd_perf.c:(.text):undefined-reference-to-perf_pmu_unregister

Similar build failure in nds32 architecture:
nd_perf.c:(.text+0x21e): undefined reference to `perf_pmu_migrate_context'
nd_perf.c:(.text+0x434): undefined reference to `perf_pmu_register'
nd_perf.c:(.text+0x57c): undefined reference to `perf_pmu_unregister'

Fix this issue by adding check for CONFIG_PERF_EVENTS config option
and disabling the nvdimm perf interface incase this config is not set.

Also remove function declaration of perf_pmu_migrate_context,
perf_pmu_register, perf_pmu_unregister functions from nd.h as these are
common pmu functions which are part of perf_event.h and since we
are disabling nvdimm perf interface incase CONFIG_PERF_EVENTS option
is not set, we not need to declare them in nd.h

Also move the platform_device header file addition part from nd.h to
nd_perf.c and add stub functions for register_nvdimm_pmu and
unregister_nvdimm_pmu functions to handle CONFIG_PERF_EVENTS=n
case.

Fixes: 0fab1ba6ad6b ("drivers/nvdimm: Add perf interface to expose
nvdimm performance stats") (Commit id based on libnvdimm-for-next tree)
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Link: https://lore.kernel.org/all/62317124.YBQFU33+s%2FwdvWGj%25lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
---
 drivers/nvdimm/Makefile  |  2 +-
 drivers/nvdimm/nd_perf.c |  1 +
 include/linux/nd.h       | 16 ++++++++++++----
 3 files changed, 14 insertions(+), 5 deletions(-)

---
Changelog:

v1 -> v2
- Rebase and tested the fix patch changes on top of libnvdimm-for-next branch

- Add stub functions for register_nvdimm_pmu and unregister_nvdimm_pmu
  functions to handle CONFIG_PERF_EVENTS=n case as suggested by Dan Williams

- Move the platform_device header file addition part from nd.h to
  nd_perf.c and just forward declare struct platform_device in nd.h
---

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/drivers/nvdimm/nd_perf.c b/drivers/nvdimm/nd_perf.c
index 314415894acf..433bbb68ae64 100644
--- a/drivers/nvdimm/nd_perf.c
+++ b/drivers/nvdimm/nd_perf.c
@@ -10,6 +10,7 @@
 #define pr_fmt(fmt) "nvdimm_pmu: " fmt
 
 #include <linux/nd.h>
+#include <linux/platform_device.h>
 
 #define EVENT(_name, _code)     enum{_name = _code}
 
diff --git a/include/linux/nd.h b/include/linux/nd.h
index 7b2ccbdc1cbc..f3e91c891cbc 100644
--- a/include/linux/nd.h
+++ b/include/linux/nd.h
@@ -9,7 +9,6 @@
 #include <linux/device.h>
 #include <linux/badblocks.h>
 #include <linux/perf_event.h>
-#include <linux/platform_device.h>
 
 enum nvdimm_event {
 	NVDIMM_REVALIDATE_POISON,
@@ -57,15 +56,24 @@ struct nvdimm_pmu {
 	struct cpumask arch_cpumask;
 };
 
+struct platform_device;
+
+#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 *nvdimm, 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;
-- 
2.31.1

[v2 PATCH 2/2] powerpc/papr_scm: Fix build failure when

[Kajol Jain]

The following build failure occurs 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 also add stub function for papr_scm_pmu_register to handle
the CONFIG_PERF_EVENTS=n case. Also move the position of macro
"to_nvdimm_pmu" inorder to merge it in CONFIG_PERF_EVENTS=y block.

Fixes: 4c08d4bbc089 ("powerpc/papr_scm: Add perf interface support") (Commit id
based on libnvdimm-for-next tree)
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
---
 arch/powerpc/platforms/pseries/papr_scm.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

---
Changelog:
v1 -> v2
- Rebase and tested the fix patch changes on top of libnvdimm-for-next branch

- Add stub function for papr_scm_pmu_register function to handle
  the CONFIG_PERF_EVENTS=n case.

- Move the position of macro "to_nvdimm_pmu" inorder to merge it in CONFIG_PERF_EVENTS=y
  block.

- The initial part of arch/powerpc/platforms/pseries/papr_scm.c could be moved to a
  headerfile, will work on this in the follow up patchset.
---
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 4dd513d7c029..9dba9e71fde9 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 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.
-- 
2.31.1