perf: Use device_show_string() helper for sysfs attributes

Deduplicate sysfs ->show() callbacks which expose a string at a static
memory location. Use the newly introduced device_show_string() helper
in the driver core instead by declaring those sysfs attributes with
DEVICE_STRING_ATTR_RO().

No functional change intended.

Signed-off-by: Lukas Wunner <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

arch/x86/events/intel/core.c

···
 
 static char pmu_name_str[30];
 
-static ssize_t pmu_name_show(struct device *cdev,
-			     struct device_attribute *attr,
-			     char *buf)
-{
-	return snprintf(buf, PAGE_SIZE, "%s\n", pmu_name_str);
-}
-
-static DEVICE_ATTR_RO(pmu_name);
+static DEVICE_STRING_ATTR_RO(pmu_name, 0444, pmu_name_str);
 
 static struct attribute *intel_pmu_caps_attrs[] = {
-       &dev_attr_pmu_name.attr,
-       NULL
+	&dev_attr_pmu_name.attr.attr,
+	NULL
 };
 
 static DEVICE_ATTR(allow_tsx_force_abort, 0644,

drivers/perf/alibaba_uncore_drw_pmu.c

···
 	.attrs = ali_drw_pmu_cpumask_attrs,
 };
 
-static ssize_t ali_drw_pmu_identifier_show(struct device *dev,
-					struct device_attribute *attr,
-					char *page)
-{
-	return sysfs_emit(page, "%s\n", "ali_drw_pmu");
-}
-
 static umode_t ali_drw_pmu_identifier_attr_visible(struct kobject *kobj,
 						struct attribute *attr, int n)
 {
 	return attr->mode;
 }
 
-static struct device_attribute ali_drw_pmu_identifier_attr =
-	__ATTR(identifier, 0444, ali_drw_pmu_identifier_show, NULL);
+static DEVICE_STRING_ATTR_RO(ali_drw_pmu_identifier, 0444, "ali_drw_pmu");
 
 static struct attribute *ali_drw_pmu_identifier_attrs[] = {
-	&ali_drw_pmu_identifier_attr.attr,
+	&dev_attr_ali_drw_pmu_identifier.attr.attr,
 	NULL
 };
 

drivers/perf/arm-cci.c

···
 
 static void pmu_write_counters(struct cci_pmu *cci_pmu,
 				 unsigned long *mask);
-static ssize_t __maybe_unused cci_pmu_format_show(struct device *dev,
-			struct device_attribute *attr, char *buf);
 static ssize_t __maybe_unused cci_pmu_event_show(struct device *dev,
 			struct device_attribute *attr, char *buf);
 
···
 	})[0].attr.attr
 
 #define CCI_FORMAT_EXT_ATTR_ENTRY(_name, _config) \
-	CCI_EXT_ATTR_ENTRY(_name, cci_pmu_format_show, (char *)_config)
+	CCI_EXT_ATTR_ENTRY(_name, device_show_string, _config)
 #define CCI_EVENT_EXT_ATTR_ENTRY(_name, _config) \
 	CCI_EXT_ATTR_ENTRY(_name, cci_pmu_event_show, (unsigned long)_config)
 
···
 	/* Disable all the PMU counters. */
 	val = readl_relaxed(cci_pmu->ctrl_base + CCI_PMCR) & ~CCI_PMCR_CEN;
 	writel(val, cci_pmu->ctrl_base + CCI_PMCR);
-}
-
-static ssize_t cci_pmu_format_show(struct device *dev,
-			struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr = container_of(attr,
-				struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
 }
 
 static ssize_t cci_pmu_event_show(struct device *dev,

drivers/perf/arm-ccn.c

···
 	*config |= (node_xp << 0) | (type << 8) | (port << 24);
 }
 
-static ssize_t arm_ccn_pmu_format_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *ea = container_of(attr,
-			struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)ea->var);
-}
-
 #define CCN_FORMAT_ATTR(_name, _config) \
 	struct dev_ext_attribute arm_ccn_pmu_format_attr_##_name = \
-			{ __ATTR(_name, S_IRUGO, arm_ccn_pmu_format_show, \
+			{ __ATTR(_name, S_IRUGO, device_show_string, \
 			NULL), _config }
 
 static CCN_FORMAT_ATTR(node, "config:0-7");

drivers/perf/arm_cspmu/arm_cspmu.c

···
 	return attr->mode;
 }
 
-ssize_t arm_cspmu_sysfs_format_show(struct device *dev,
-				struct device_attribute *attr,
-				char *buf)
-{
-	struct dev_ext_attribute *eattr =
-		container_of(attr, struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-EXPORT_SYMBOL_GPL(arm_cspmu_sysfs_format_show);
-
 static struct attribute *arm_cspmu_format_attrs[] = {
 	ARM_CSPMU_FORMAT_EVENT_ATTR,
 	ARM_CSPMU_FORMAT_FILTER_ATTR,

drivers/perf/arm_cspmu/arm_cspmu.h

···
 	})[0].attr.attr)
 
 #define ARM_CSPMU_FORMAT_ATTR(_name, _config)				\
-	ARM_CSPMU_EXT_ATTR(_name, arm_cspmu_sysfs_format_show, (char *)_config)
+	ARM_CSPMU_EXT_ATTR(_name, device_show_string, _config)
 
 #define ARM_CSPMU_EVENT_ATTR(_name, _config)				\
 	PMU_EVENT_ATTR_ID(_name, arm_cspmu_sysfs_event_show, _config)
···
 ssize_t arm_cspmu_sysfs_event_show(struct device *dev,
 				   struct device_attribute *attr,
 				   char *buf);
-
-/* Default function to show format attribute in sysfs. */
-ssize_t arm_cspmu_sysfs_format_show(struct device *dev,
-				    struct device_attribute *attr,
-				    char *buf);
 
 /* Register vendor backend. */
 int arm_cspmu_impl_register(const struct arm_cspmu_impl_match *impl_match);

drivers/perf/arm_dsu_pmu.c

···
 	DSU_EXT_ATTR(_name, dsu_pmu_sysfs_event_show, (unsigned long)_config)
 
 #define DSU_FORMAT_ATTR(_name, _config)		\
-	DSU_EXT_ATTR(_name, dsu_pmu_sysfs_format_show, (char *)_config)
+	DSU_EXT_ATTR(_name, device_show_string, _config)
 
 #define DSU_CPUMASK_ATTR(_name, _config)	\
 	DSU_EXT_ATTR(_name, dsu_pmu_cpumask_show, (unsigned long)_config)
···
 	struct dev_ext_attribute *eattr = container_of(attr,
 					struct dev_ext_attribute, attr);
 	return sysfs_emit(buf, "event=0x%lx\n", (unsigned long)eattr->var);
-}
-
-static ssize_t dsu_pmu_sysfs_format_show(struct device *dev,
-					 struct device_attribute *attr,
-					 char *buf)
-{
-	struct dev_ext_attribute *eattr = container_of(attr,
-					struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
 }
 
 static ssize_t dsu_pmu_cpumask_show(struct device *dev,

drivers/perf/cxl_pmu.c

···
 	return 0;
 }
 
-static ssize_t cxl_pmu_format_sysfs_show(struct device *dev,
-					 struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-
 #define CXL_PMU_FORMAT_ATTR(_name, _format)\
 	(&((struct dev_ext_attribute[]) {					\
 		{								\
-			.attr = __ATTR(_name, 0444,				\
-				       cxl_pmu_format_sysfs_show, NULL),	\
+			.attr = __ATTR(_name, 0444, device_show_string, NULL),	\
 			.var = (void *)_format					\
 		}								\
 		})[0].attr.attr)

drivers/perf/hisilicon/hisi_pcie_pmu.c

···
 HISI_PCIE_PMU_FILTER_ATTR(port, config2, 15, 0);
 HISI_PCIE_PMU_FILTER_ATTR(bdf, config2, 31, 16);
 
-static ssize_t hisi_pcie_format_sysfs_show(struct device *dev, struct device_attribute *attr,
-					   char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-
 static ssize_t hisi_pcie_event_sysfs_show(struct device *dev, struct device_attribute *attr,
 					  char *buf)
 {
···
 
 #define HISI_PCIE_PMU_FORMAT_ATTR(_name, _format)                              \
 	(&((struct dev_ext_attribute[]){                                       \
-		{ .attr = __ATTR(_name, 0444, hisi_pcie_format_sysfs_show,     \
-				 NULL),                                        \
+		{ .attr = __ATTR(_name, 0444, device_show_string, NULL),       \
 		  .var = (void *)_format }                                     \
 	})[0].attr.attr)
 

drivers/perf/hisilicon/hisi_uncore_pmu.c

···
 #define HISI_MAX_PERIOD(nr) (GENMASK_ULL((nr) - 1, 0))
 
 /*
- * PMU format attributes
- */
-ssize_t hisi_format_sysfs_show(struct device *dev,
-			       struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-EXPORT_SYMBOL_GPL(hisi_format_sysfs_show);
-
-/*
  * PMU event attributes
  */
 ssize_t hisi_event_sysfs_show(struct device *dev,

drivers/perf/hisilicon/hisi_uncore_pmu.h

···
 	})[0].attr.attr)
 
 #define HISI_PMU_FORMAT_ATTR(_name, _config)		\
-	HISI_PMU_ATTR(_name, hisi_format_sysfs_show, (void *)_config)
+	HISI_PMU_ATTR(_name, device_show_string, _config)
 #define HISI_PMU_EVENT_ATTR(_name, _config)		\
 	HISI_PMU_ATTR(_name, hisi_event_sysfs_show, (unsigned long)_config)
 
···
 void hisi_uncore_pmu_disable(struct pmu *pmu);
 ssize_t hisi_event_sysfs_show(struct device *dev,
 			      struct device_attribute *attr, char *buf);
-ssize_t hisi_format_sysfs_show(struct device *dev,
-			       struct device_attribute *attr, char *buf);
 ssize_t hisi_cpumask_sysfs_show(struct device *dev,
 				struct device_attribute *attr, char *buf);
 int hisi_uncore_pmu_online_cpu(unsigned int cpu, struct hlist_node *node);

drivers/perf/hisilicon/hns3_pmu.c

···
 	HNS3_PMU_EVT_PPS_##_name##_TIME,				\
 	HNS3_PMU_FILTER_INTR_##_name})
 
-static ssize_t hns3_pmu_format_show(struct device *dev,
-				    struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sysfs_emit(buf, "%s\n", (char *)eattr->var);
-}
-
 static ssize_t hns3_pmu_event_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
 {
···
 	})[0].attr.attr)
 
 #define HNS3_PMU_FORMAT_ATTR(_name, _format) \
-	HNS3_PMU_ATTR(_name, hns3_pmu_format_show, (void *)_format)
+	HNS3_PMU_ATTR(_name, device_show_string, _format)
 #define HNS3_PMU_EVENT_ATTR(_name, _event) \
 	HNS3_PMU_ATTR(_name, hns3_pmu_event_show, (void *)_event)
 #define HNS3_PMU_FLT_MODE_ATTR(_name, _event) \

drivers/perf/qcom_l3_pmu.c

···
 
 /* formats */
 
-static ssize_t l3cache_pmu_format_show(struct device *dev,
-				       struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *) eattr->var);
-}
-
 #define L3CACHE_PMU_FORMAT_ATTR(_name, _config)				      \
 	(&((struct dev_ext_attribute[]) {				      \
-		{ .attr = __ATTR(_name, 0444, l3cache_pmu_format_show, NULL), \
+		{ .attr = __ATTR(_name, 0444, device_show_string, NULL),      \
 		  .var = (void *) _config, }				      \
 	})[0].attr.attr)
 

drivers/perf/xgene_pmu.c

···
 /*
  * sysfs format attributes
  */
-static ssize_t xgene_pmu_format_show(struct device *dev,
-				     struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *eattr;
-
-	eattr = container_of(attr, struct dev_ext_attribute, attr);
-	return sysfs_emit(buf, "%s\n", (char *) eattr->var);
-}
-
 #define XGENE_PMU_FORMAT_ATTR(_name, _config)		\
 	(&((struct dev_ext_attribute[]) {		\
-		{ .attr = __ATTR(_name, S_IRUGO, xgene_pmu_format_show, NULL), \
+		{ .attr = __ATTR(_name, S_IRUGO, device_show_string, NULL), \
 		  .var = (void *) _config, }		\
 	})[0].attr.attr)