[PATCH 0/6] Deduplicate string exposure in sysfs

[PATCH 0/6] Deduplicate string exposure in sysfs

[Lukas Wunner]

Introduce a generic ->show() callback to expose a string as a device
attribute in sysfs.  Deduplicate various identical callbacks across
the tree.

Result:  Minus 216 LoC, minus 1576 bytes vmlinux size (x86_64 allyesconfig).

This is a byproduct of my upcoming PCI device authentication v2 patches.


Lukas Wunner (6):
  driver core: Add device_show_string() helper for sysfs attributes
  hwmon: Use device_show_string() helper for sysfs attributes
  IB/qib: Use device_show_string() helper for sysfs attributes
  perf: Use device_show_string() helper for sysfs attributes
  platform/x86: Use device_show_string() helper for sysfs attributes
  scsi: Use device_show_string() helper for sysfs attributes

 arch/powerpc/perf/hv-24x7.c              | 10 ----
 arch/x86/events/intel/core.c             | 13 ++---
 drivers/base/core.c                      |  9 ++++
 drivers/hwmon/i5k_amb.c                  | 15 ++----
 drivers/hwmon/ibmpex.c                   | 14 ++----
 drivers/infiniband/hw/qib/qib.h          |  1 -
 drivers/infiniband/hw/qib/qib_driver.c   |  6 ---
 drivers/infiniband/hw/qib/qib_sysfs.c    | 10 +---
 drivers/perf/alibaba_uncore_drw_pmu.c    | 12 +----
 drivers/perf/arm-cci.c                   | 12 +----
 drivers/perf/arm-ccn.c                   | 11 +----
 drivers/perf/arm_cspmu/arm_cspmu.c       | 10 ----
 drivers/perf/arm_cspmu/arm_cspmu.h       |  7 +--
 drivers/perf/arm_dsu_pmu.c               | 11 +----
 drivers/perf/cxl_pmu.c                   | 13 +----
 drivers/perf/hisilicon/hisi_pcie_pmu.c   | 13 +----
 drivers/perf/hisilicon/hisi_uncore_pmu.c | 14 ------
 drivers/perf/hisilicon/hisi_uncore_pmu.h |  4 +-
 drivers/perf/hisilicon/hns3_pmu.c        | 12 +----
 drivers/perf/qcom_l3_pmu.c               | 11 +----
 drivers/perf/xgene_pmu.c                 | 11 +----
 drivers/platform/x86/asus-wmi.c          | 62 ++++++------------------
 drivers/platform/x86/thinkpad_acpi.c     | 10 +---
 drivers/platform/x86/toshiba_acpi.c      |  9 +---
 drivers/scsi/bfa/bfad_attr.c             | 28 +++--------
 drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 11 +----
 drivers/scsi/mvsas/mv_init.c             | 10 +---
 drivers/scsi/qla2xxx/qla_attr.c          | 11 +----
 drivers/scsi/smartpqi/smartpqi_init.c    | 11 ++---
 include/linux/device.h                   | 15 ++++++
 30 files changed, 85 insertions(+), 301 deletions(-)

-- 
2.43.0

[PATCH 1/6] driver core: Add device_show_string() helper for sysfs attributes

[Lukas Wunner]

For drivers wishing to expose an unsigned long, int or bool at a static
memory location in sysfs, the driver core provides ready-made helpers
such as device_show_ulong() to be used as ->show() callback.

Some drivers need to expose a string and so far they all provide their
own ->show() implementation.  arch/powerpc/perf/hv-24x7.c went so far
as to create a device_show_string() helper but kept it private.

Make it public for reuse by other drivers.  The pattern seems to be
sufficiently frequent to merit a public helper.

Add a DEVICE_STRING_ATTR_RO() macro in line with the existing
DEVICE_ULONG_ATTR() and similar macros to ease declaration of string
attributes.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 arch/powerpc/perf/hv-24x7.c | 10 ----------
 drivers/base/core.c         |  9 +++++++++
 include/linux/device.h      | 15 +++++++++++++++
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index 057ec2e3451d..d400fa391c27 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -425,16 +425,6 @@ static char *memdup_to_str(char *maybe_str, int max_len, gfp_t gfp)
 	return kasprintf(gfp, "%.*s", max_len, maybe_str);
 }
 
-static ssize_t device_show_string(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct dev_ext_attribute *d;
-
-	d = container_of(attr, struct dev_ext_attribute, attr);
-
-	return sprintf(buf, "%s\n", (char *)d->var);
-}
-
 static ssize_t cpumask_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 78dfa74ee18b..190d4a39c6a8 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2523,6 +2523,15 @@ ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
 }
 EXPORT_SYMBOL_GPL(device_show_bool);
 
+ssize_t device_show_string(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct dev_ext_attribute *ea = to_ext_attr(attr);
+
+	return sysfs_emit(buf, "%s\n", (char *)ea->var);
+}
+EXPORT_SYMBOL_GPL(device_show_string);
+
 /**
  * device_release - free device structure.
  * @kobj: device's kobject.
diff --git a/include/linux/device.h b/include/linux/device.h
index c515ba5756e4..63ac65db3ecb 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -132,6 +132,8 @@ ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
 			char *buf);
 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
 			 const char *buf, size_t count);
+ssize_t device_show_string(struct device *dev, struct device_attribute *attr,
+			   char *buf);
 
 /**
  * DEVICE_ATTR - Define a device attribute.
@@ -251,6 +253,19 @@ ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
 	struct dev_ext_attribute dev_attr_##_name = \
 		{ __ATTR(_name, _mode, device_show_bool, device_store_bool), &(_var) }
 
+/**
+ * DEVICE_STRING_ATTR_RO - Define a device attribute backed by a r/o string.
+ * @_name: Attribute name.
+ * @_mode: File mode.
+ * @_var: Identifier of string.
+ *
+ * Like DEVICE_ULONG_ATTR(), but @_var is a string. Because the length of the
+ * string allocation is unknown, the attribute must be read-only.
+ */
+#define DEVICE_STRING_ATTR_RO(_name, _mode, _var) \
+	struct dev_ext_attribute dev_attr_##_name = \
+		{ __ATTR(_name, (_mode) & ~0222, device_show_string, NULL), (_var) }
+
 #define DEVICE_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
 	struct device_attribute dev_attr_##_name =		\
 		__ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
-- 
2.43.0

[PATCH 2/6] hwmon: Use device_show_string() helper for sysfs attributes

[Lukas Wunner]

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 <lukas@wunner.de>
---
 drivers/hwmon/i5k_amb.c | 15 ++++-----------
 drivers/hwmon/ibmpex.c  | 14 ++++----------
 2 files changed, 8 insertions(+), 21 deletions(-)

diff --git a/drivers/hwmon/i5k_amb.c b/drivers/hwmon/i5k_amb.c
index ff48913fe6bf..02f5d35dd319 100644
--- a/drivers/hwmon/i5k_amb.c
+++ b/drivers/hwmon/i5k_amb.c
@@ -101,14 +101,7 @@ struct i5k_amb_data {
 	unsigned int num_attrs;
 };
 
-static ssize_t name_show(struct device *dev, struct device_attribute *devattr,
-			 char *buf)
-{
-	return sprintf(buf, "%s\n", DRVNAME);
-}
-
-
-static DEVICE_ATTR_RO(name);
+static DEVICE_STRING_ATTR_RO(name, 0444, DRVNAME);
 
 static struct platform_device *amb_pdev;
 
@@ -373,7 +366,7 @@ static int i5k_amb_hwmon_init(struct platform_device *pdev)
 		}
 	}
 
-	res = device_create_file(&pdev->dev, &dev_attr_name);
+	res = device_create_file(&pdev->dev, &dev_attr_name.attr);
 	if (res)
 		goto exit_remove;
 
@@ -386,7 +379,7 @@ static int i5k_amb_hwmon_init(struct platform_device *pdev)
 	return res;
 
 exit_remove:
-	device_remove_file(&pdev->dev, &dev_attr_name);
+	device_remove_file(&pdev->dev, &dev_attr_name.attr);
 	for (i = 0; i < data->num_attrs; i++)
 		device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
 	kfree(data->attrs);
@@ -561,7 +554,7 @@ static void i5k_amb_remove(struct platform_device *pdev)
 	struct i5k_amb_data *data = platform_get_drvdata(pdev);
 
 	hwmon_device_unregister(data->hwmon_dev);
-	device_remove_file(&pdev->dev, &dev_attr_name);
+	device_remove_file(&pdev->dev, &dev_attr_name.attr);
 	for (i = 0; i < data->num_attrs; i++)
 		device_remove_file(&pdev->dev, &data->attrs[i].s_attr.dev_attr);
 	kfree(data->attrs);
diff --git a/drivers/hwmon/ibmpex.c b/drivers/hwmon/ibmpex.c
index db066b368918..228c5f6c6f38 100644
--- a/drivers/hwmon/ibmpex.c
+++ b/drivers/hwmon/ibmpex.c
@@ -256,12 +256,7 @@ static struct ibmpex_bmc_data *get_bmc_data(int iface)
 	return NULL;
 }
 
-static ssize_t name_show(struct device *dev, struct device_attribute *devattr,
-			 char *buf)
-{
-	return sprintf(buf, "%s\n", DRVNAME);
-}
-static SENSOR_DEVICE_ATTR_RO(name, name, 0);
+static DEVICE_STRING_ATTR_RO(name, 0444, DRVNAME);
 
 static ssize_t ibmpex_show_sensor(struct device *dev,
 				  struct device_attribute *devattr,
@@ -415,8 +410,7 @@ static int ibmpex_find_sensors(struct ibmpex_bmc_data *data)
 	if (err)
 		goto exit_remove;
 
-	err = device_create_file(data->bmc_device,
-			&sensor_dev_attr_name.dev_attr);
+	err = device_create_file(data->bmc_device, &dev_attr_name.attr);
 	if (err)
 		goto exit_remove;
 
@@ -425,7 +419,7 @@ static int ibmpex_find_sensors(struct ibmpex_bmc_data *data)
 exit_remove:
 	device_remove_file(data->bmc_device,
 			   &sensor_dev_attr_reset_high_low.dev_attr);
-	device_remove_file(data->bmc_device, &sensor_dev_attr_name.dev_attr);
+	device_remove_file(data->bmc_device, &dev_attr_name.attr);
 	for (i = 0; i < data->num_sensors; i++)
 		for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
 			if (!data->sensors[i].attr[j].dev_attr.attr.name)
@@ -516,7 +510,7 @@ static void ibmpex_bmc_delete(struct ibmpex_bmc_data *data)
 
 	device_remove_file(data->bmc_device,
 			   &sensor_dev_attr_reset_high_low.dev_attr);
-	device_remove_file(data->bmc_device, &sensor_dev_attr_name.dev_attr);
+	device_remove_file(data->bmc_device, &dev_attr_name.attr);
 	for (i = 0; i < data->num_sensors; i++)
 		for (j = 0; j < PEX_NUM_SENSOR_FUNCS; j++) {
 			if (!data->sensors[i].attr[j].dev_attr.attr.name)
-- 
2.43.0

[PATCH 3/6] IB/qib: Use device_show_string() helper for sysfs attributes

[Lukas Wunner]

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 <lukas@wunner.de>
---
 drivers/infiniband/hw/qib/qib.h        |  1 -
 drivers/infiniband/hw/qib/qib_driver.c |  6 ------
 drivers/infiniband/hw/qib/qib_sysfs.c  | 10 ++--------
 3 files changed, 2 insertions(+), 15 deletions(-)

diff --git a/drivers/infiniband/hw/qib/qib.h b/drivers/infiniband/hw/qib/qib.h
index 26c615772be3..8ee4edd7883c 100644
--- a/drivers/infiniband/hw/qib/qib.h
+++ b/drivers/infiniband/hw/qib/qib.h
@@ -1359,7 +1359,6 @@ static inline u32 qib_get_rcvhdrtail(const struct qib_ctxtdata *rcd)
  * sysfs interface.
  */
 
-extern const char ib_qib_version[];
 extern const struct attribute_group qib_attr_group;
 extern const struct attribute_group *qib_attr_port_groups[];
 
diff --git a/drivers/infiniband/hw/qib/qib_driver.c b/drivers/infiniband/hw/qib/qib_driver.c
index bf3fa12fe935..4fcbef99e400 100644
--- a/drivers/infiniband/hw/qib/qib_driver.c
+++ b/drivers/infiniband/hw/qib/qib_driver.c
@@ -44,12 +44,6 @@
 
 #include "qib.h"
 
-/*
- * The size has to be longer than this string, so we can append
- * board/chip information to it in the init code.
- */
-const char ib_qib_version[] = QIB_DRIVER_VERSION "\n";
-
 DEFINE_MUTEX(qib_mutex);	/* general driver use */
 
 unsigned qib_ibmtu;
diff --git a/drivers/infiniband/hw/qib/qib_sysfs.c b/drivers/infiniband/hw/qib/qib_sysfs.c
index 41c272980f91..53ec7510e4eb 100644
--- a/drivers/infiniband/hw/qib/qib_sysfs.c
+++ b/drivers/infiniband/hw/qib/qib_sysfs.c
@@ -585,13 +585,7 @@ static ssize_t hca_type_show(struct device *device,
 static DEVICE_ATTR_RO(hca_type);
 static DEVICE_ATTR(board_id, 0444, hca_type_show, NULL);
 
-static ssize_t version_show(struct device *device,
-			    struct device_attribute *attr, char *buf)
-{
-	/* The string printed here is already newline-terminated. */
-	return sysfs_emit(buf, "%s", (char *)ib_qib_version);
-}
-static DEVICE_ATTR_RO(version);
+static DEVICE_STRING_ATTR_RO(version, 0444, QIB_DRIVER_VERSION);
 
 static ssize_t boardversion_show(struct device *device,
 				 struct device_attribute *attr, char *buf)
@@ -721,7 +715,7 @@ static struct attribute *qib_attributes[] = {
 	&dev_attr_hw_rev.attr,
 	&dev_attr_hca_type.attr,
 	&dev_attr_board_id.attr,
-	&dev_attr_version.attr,
+	&dev_attr_version.attr.attr,
 	&dev_attr_nctxts.attr,
 	&dev_attr_nfreectxts.attr,
 	&dev_attr_serial.attr,
-- 
2.43.0

[PATCH 4/6] perf: Use device_show_string() helper for sysfs attributes

[Lukas Wunner]

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 <lukas@wunner.de>
---
 arch/x86/events/intel/core.c             | 13 +++----------
 drivers/perf/alibaba_uncore_drw_pmu.c    | 12 ++----------
 drivers/perf/arm-cci.c                   | 12 +-----------
 drivers/perf/arm-ccn.c                   | 11 +----------
 drivers/perf/arm_cspmu/arm_cspmu.c       | 10 ----------
 drivers/perf/arm_cspmu/arm_cspmu.h       |  7 +------
 drivers/perf/arm_dsu_pmu.c               | 11 +----------
 drivers/perf/cxl_pmu.c                   | 13 +------------
 drivers/perf/hisilicon/hisi_pcie_pmu.c   | 13 +------------
 drivers/perf/hisilicon/hisi_uncore_pmu.c | 14 --------------
 drivers/perf/hisilicon/hisi_uncore_pmu.h |  4 +---
 drivers/perf/hisilicon/hns3_pmu.c        | 12 +-----------
 drivers/perf/qcom_l3_pmu.c               | 11 +----------
 drivers/perf/xgene_pmu.c                 | 11 +----------
 14 files changed, 15 insertions(+), 139 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 768d1414897f..38c1b1f1deaa 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -5645,18 +5645,11 @@ lbr_is_visible(struct kobject *kobj, struct attribute *attr, int i)
 
 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,
diff --git a/drivers/perf/alibaba_uncore_drw_pmu.c b/drivers/perf/alibaba_uncore_drw_pmu.c
index a9277dcf90ce..a82592e131ba 100644
--- a/drivers/perf/alibaba_uncore_drw_pmu.c
+++ b/drivers/perf/alibaba_uncore_drw_pmu.c
@@ -236,24 +236,16 @@ static const struct attribute_group ali_drw_pmu_cpumask_attr_group = {
 	.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
 };
 
diff --git a/drivers/perf/arm-cci.c b/drivers/perf/arm-cci.c
index 6be03f81ae5d..e516edc933f2 100644
--- a/drivers/perf/arm-cci.c
+++ b/drivers/perf/arm-cci.c
@@ -127,8 +127,6 @@ enum cci_models {
 
 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);
 
@@ -138,7 +136,7 @@ static ssize_t __maybe_unused cci_pmu_event_show(struct device *dev,
 	})[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)
 
@@ -688,14 +686,6 @@ static void __cci_pmu_disable(struct cci_pmu *cci_pmu)
 	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,
 			struct device_attribute *attr, char *buf)
 {
diff --git a/drivers/perf/arm-ccn.c b/drivers/perf/arm-ccn.c
index 641471bd5eff..e4408acd4450 100644
--- a/drivers/perf/arm-ccn.c
+++ b/drivers/perf/arm-ccn.c
@@ -215,18 +215,9 @@ static void arm_ccn_pmu_config_set(u64 *config, u32 node_xp, u32 type, u32 port)
 	*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");
diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c b/drivers/perf/arm_cspmu/arm_cspmu.c
index b9a252272f1e..7aff616523ec 100644
--- a/drivers/perf/arm_cspmu/arm_cspmu.c
+++ b/drivers/perf/arm_cspmu/arm_cspmu.c
@@ -223,16 +223,6 @@ arm_cspmu_event_attr_is_visible(struct kobject *kobj,
 	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,
diff --git a/drivers/perf/arm_cspmu/arm_cspmu.h b/drivers/perf/arm_cspmu/arm_cspmu.h
index c9163acfe810..2621f3111148 100644
--- a/drivers/perf/arm_cspmu/arm_cspmu.h
+++ b/drivers/perf/arm_cspmu/arm_cspmu.h
@@ -28,7 +28,7 @@
 	})[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)
@@ -167,11 +167,6 @@ 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);
 
diff --git a/drivers/perf/arm_dsu_pmu.c b/drivers/perf/arm_dsu_pmu.c
index bae3ca37f846..4e54ce9100a6 100644
--- a/drivers/perf/arm_dsu_pmu.c
+++ b/drivers/perf/arm_dsu_pmu.c
@@ -85,7 +85,7 @@
 	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)
@@ -139,15 +139,6 @@ static ssize_t dsu_pmu_sysfs_event_show(struct device *dev,
 	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,
 				    struct device_attribute *attr,
 				    char *buf)
diff --git a/drivers/perf/cxl_pmu.c b/drivers/perf/cxl_pmu.c
index 308c9969642e..c41263c7fe5c 100644
--- a/drivers/perf/cxl_pmu.c
+++ b/drivers/perf/cxl_pmu.c
@@ -208,21 +208,10 @@ static int cxl_pmu_parse_caps(struct device *dev, struct cxl_pmu_info *info)
 	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)
diff --git a/drivers/perf/hisilicon/hisi_pcie_pmu.c b/drivers/perf/hisilicon/hisi_pcie_pmu.c
index 5d1f0e9fdb08..dfd1f448f3fc 100644
--- a/drivers/perf/hisilicon/hisi_pcie_pmu.c
+++ b/drivers/perf/hisilicon/hisi_pcie_pmu.c
@@ -99,16 +99,6 @@ HISI_PCIE_PMU_FILTER_ATTR(len_mode, config1, 11, 10);
 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)
 {
@@ -120,8 +110,7 @@ static ssize_t hisi_pcie_event_sysfs_show(struct device *dev, struct device_attr
 
 #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)
 
diff --git a/drivers/perf/hisilicon/hisi_uncore_pmu.c b/drivers/perf/hisilicon/hisi_uncore_pmu.c
index 04031450d5fe..382c5567e4e2 100644
--- a/drivers/perf/hisilicon/hisi_uncore_pmu.c
+++ b/drivers/perf/hisilicon/hisi_uncore_pmu.c
@@ -22,20 +22,6 @@
 
 #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
  */
diff --git a/drivers/perf/hisilicon/hisi_uncore_pmu.h b/drivers/perf/hisilicon/hisi_uncore_pmu.h
index 92402aa69d70..25b2d43b72bf 100644
--- a/drivers/perf/hisilicon/hisi_uncore_pmu.h
+++ b/drivers/perf/hisilicon/hisi_uncore_pmu.h
@@ -33,7 +33,7 @@
 	})[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)
 
@@ -122,8 +122,6 @@ void hisi_uncore_pmu_enable(struct pmu *pmu);
 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);
diff --git a/drivers/perf/hisilicon/hns3_pmu.c b/drivers/perf/hisilicon/hns3_pmu.c
index 16869bf5bf4c..6d9725bdff83 100644
--- a/drivers/perf/hisilicon/hns3_pmu.c
+++ b/drivers/perf/hisilicon/hns3_pmu.c
@@ -363,16 +363,6 @@ HNS3_PMU_FILTER_ATTR(global, config1, 52, 52);
 	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)
 {
@@ -421,7 +411,7 @@ static ssize_t hns3_pmu_filter_mode_show(struct device *dev,
 	})[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) \
diff --git a/drivers/perf/qcom_l3_pmu.c b/drivers/perf/qcom_l3_pmu.c
index f16783d03db7..5fc53781afba 100644
--- a/drivers/perf/qcom_l3_pmu.c
+++ b/drivers/perf/qcom_l3_pmu.c
@@ -609,18 +609,9 @@ static void qcom_l3_cache__event_read(struct perf_event *event)
 
 /* 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)
 
diff --git a/drivers/perf/xgene_pmu.c b/drivers/perf/xgene_pmu.c
index 0d49343d704b..79279a359995 100644
--- a/drivers/perf/xgene_pmu.c
+++ b/drivers/perf/xgene_pmu.c
@@ -162,18 +162,9 @@ enum xgene_pmu_dev_type {
 /*
  * 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)
 
-- 
2.43.0

[PATCH 5/6] platform/x86: Use device_show_string() helper for sysfs attributes

[Lukas Wunner]

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 <lukas@wunner.de>
---
 drivers/platform/x86/asus-wmi.c      | 62 +++++++---------------------
 drivers/platform/x86/thinkpad_acpi.c | 10 +----
 drivers/platform/x86/toshiba_acpi.c  |  9 +---
 3 files changed, 20 insertions(+), 61 deletions(-)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 3f07bbf809ef..78d7579b2fdd 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -915,17 +915,12 @@ static ssize_t kbd_rgb_mode_store(struct device *dev,
 }
 static DEVICE_ATTR_WO(kbd_rgb_mode);
 
-static ssize_t kbd_rgb_mode_index_show(struct device *device,
-						 struct device_attribute *attr,
-						 char *buf)
-{
-	return sysfs_emit(buf, "%s\n", "cmd mode red green blue speed");
-}
-static DEVICE_ATTR_RO(kbd_rgb_mode_index);
+static DEVICE_STRING_ATTR_RO(kbd_rgb_mode_index, 0444,
+			     "cmd mode red green blue speed");
 
 static struct attribute *kbd_rgb_mode_attrs[] = {
 	&dev_attr_kbd_rgb_mode.attr,
-	&dev_attr_kbd_rgb_mode_index.attr,
+	&dev_attr_kbd_rgb_mode_index.attr.attr,
 	NULL,
 };
 
@@ -967,17 +962,12 @@ static ssize_t kbd_rgb_state_store(struct device *dev,
 }
 static DEVICE_ATTR_WO(kbd_rgb_state);
 
-static ssize_t kbd_rgb_state_index_show(struct device *device,
-						 struct device_attribute *attr,
-						 char *buf)
-{
-	return sysfs_emit(buf, "%s\n", "cmd boot awake sleep keyboard");
-}
-static DEVICE_ATTR_RO(kbd_rgb_state_index);
+static DEVICE_STRING_ATTR_RO(kbd_rgb_state_index, 0444,
+			     "cmd boot awake sleep keyboard");
 
 static struct attribute *kbd_rgb_state_attrs[] = {
 	&dev_attr_kbd_rgb_state.attr,
-	&dev_attr_kbd_rgb_state_index.attr,
+	&dev_attr_kbd_rgb_state_index.attr.attr,
 	NULL,
 };
 
@@ -2493,13 +2483,6 @@ static ssize_t pwm1_enable_store(struct device *dev,
 	return count;
 }
 
-static ssize_t fan1_label_show(struct device *dev,
-					  struct device_attribute *attr,
-					  char *buf)
-{
-	return sysfs_emit(buf, "%s\n", ASUS_FAN_DESC);
-}
-
 static ssize_t asus_hwmon_temp1(struct device *dev,
 				struct device_attribute *attr,
 				char *buf)
@@ -2534,13 +2517,6 @@ static ssize_t fan2_input_show(struct device *dev,
 	return sysfs_emit(buf, "%d\n", value * 100);
 }
 
-static ssize_t fan2_label_show(struct device *dev,
-					  struct device_attribute *attr,
-					  char *buf)
-{
-	return sysfs_emit(buf, "%s\n", ASUS_GPU_FAN_DESC);
-}
-
 /* Middle/Center fan on modern ROG laptops */
 static ssize_t fan3_input_show(struct device *dev,
 					struct device_attribute *attr,
@@ -2559,13 +2535,6 @@ static ssize_t fan3_input_show(struct device *dev,
 	return sysfs_emit(buf, "%d\n", value * 100);
 }
 
-static ssize_t fan3_label_show(struct device *dev,
-					  struct device_attribute *attr,
-					  char *buf)
-{
-	return sysfs_emit(buf, "%s\n", ASUS_MID_FAN_DESC);
-}
-
 static ssize_t pwm2_enable_show(struct device *dev,
 				struct device_attribute *attr,
 				char *buf)
@@ -2662,15 +2631,16 @@ static ssize_t pwm3_enable_store(struct device *dev,
 static DEVICE_ATTR_RW(pwm1);
 static DEVICE_ATTR_RW(pwm1_enable);
 static DEVICE_ATTR_RO(fan1_input);
-static DEVICE_ATTR_RO(fan1_label);
+static DEVICE_STRING_ATTR_RO(fan1_label, 0444, ASUS_FAN_DESC);
+
 /* Fan2 - GPU fan */
 static DEVICE_ATTR_RW(pwm2_enable);
 static DEVICE_ATTR_RO(fan2_input);
-static DEVICE_ATTR_RO(fan2_label);
+static DEVICE_STRING_ATTR_RO(fan2_label, 0444, ASUS_GPU_FAN_DESC);
 /* Fan3 - Middle/center fan */
 static DEVICE_ATTR_RW(pwm3_enable);
 static DEVICE_ATTR_RO(fan3_input);
-static DEVICE_ATTR_RO(fan3_label);
+static DEVICE_STRING_ATTR_RO(fan3_label, 0444, ASUS_MID_FAN_DESC);
 
 /* Temperature */
 static DEVICE_ATTR(temp1_input, S_IRUGO, asus_hwmon_temp1, NULL);
@@ -2681,11 +2651,11 @@ static struct attribute *hwmon_attributes[] = {
 	&dev_attr_pwm2_enable.attr,
 	&dev_attr_pwm3_enable.attr,
 	&dev_attr_fan1_input.attr,
-	&dev_attr_fan1_label.attr,
+	&dev_attr_fan1_label.attr.attr,
 	&dev_attr_fan2_input.attr,
-	&dev_attr_fan2_label.attr,
+	&dev_attr_fan2_label.attr.attr,
 	&dev_attr_fan3_input.attr,
-	&dev_attr_fan3_label.attr,
+	&dev_attr_fan3_label.attr.attr,
 
 	&dev_attr_temp1_input.attr,
 	NULL
@@ -2702,17 +2672,17 @@ static umode_t asus_hwmon_sysfs_is_visible(struct kobject *kobj,
 		if (asus->fan_type != FAN_TYPE_AGFN)
 			return 0;
 	} else if (attr == &dev_attr_fan1_input.attr
-	    || attr == &dev_attr_fan1_label.attr
+	    || attr == &dev_attr_fan1_label.attr.attr
 	    || attr == &dev_attr_pwm1_enable.attr) {
 		if (asus->fan_type == FAN_TYPE_NONE)
 			return 0;
 	} else if (attr == &dev_attr_fan2_input.attr
-	    || attr == &dev_attr_fan2_label.attr
+	    || attr == &dev_attr_fan2_label.attr.attr
 	    || attr == &dev_attr_pwm2_enable.attr) {
 		if (asus->gpu_fan_type == FAN_TYPE_NONE)
 			return 0;
 	} else if (attr == &dev_attr_fan3_input.attr
-	    || attr == &dev_attr_fan3_label.attr
+	    || attr == &dev_attr_fan3_label.attr.attr
 	    || attr == &dev_attr_pwm3_enable.attr) {
 		if (asus->mid_fan_type == FAN_TYPE_NONE)
 			return 0;
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 82429e59999d..47a64a213d14 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -10991,13 +10991,7 @@ static struct ibm_struct auxmac_data = {
 	.name = "auxmac",
 };
 
-static ssize_t auxmac_show(struct device *dev,
-			   struct device_attribute *attr,
-			   char *buf)
-{
-	return sysfs_emit(buf, "%s\n", auxmac);
-}
-static DEVICE_ATTR_RO(auxmac);
+static DEVICE_STRING_ATTR_RO(auxmac, 0444, auxmac);
 
 static umode_t auxmac_attr_is_visible(struct kobject *kobj,
 				      struct attribute *attr, int n)
@@ -11006,7 +11000,7 @@ static umode_t auxmac_attr_is_visible(struct kobject *kobj,
 }
 
 static struct attribute *auxmac_attributes[] = {
-	&dev_attr_auxmac.attr,
+	&dev_attr_auxmac.attr.attr,
 	NULL
 };
 
diff --git a/drivers/platform/x86/toshiba_acpi.c b/drivers/platform/x86/toshiba_acpi.c
index 291f14ef6702..01cf60a015bf 100644
--- a/drivers/platform/x86/toshiba_acpi.c
+++ b/drivers/platform/x86/toshiba_acpi.c
@@ -1814,12 +1814,7 @@ static DECLARE_WORK(kbd_bl_work, toshiba_acpi_kbd_bl_work);
 /*
  * Sysfs files
  */
-static ssize_t version_show(struct device *dev,
-			    struct device_attribute *attr, char *buf)
-{
-	return sprintf(buf, "%s\n", TOSHIBA_ACPI_VERSION);
-}
-static DEVICE_ATTR_RO(version);
+static DEVICE_STRING_ATTR_RO(version, 0444, TOSHIBA_ACPI_VERSION);
 
 static ssize_t fan_store(struct device *dev,
 			 struct device_attribute *attr,
@@ -2428,7 +2423,7 @@ static ssize_t cooling_method_store(struct device *dev,
 static DEVICE_ATTR_RW(cooling_method);
 
 static struct attribute *toshiba_attributes[] = {
-	&dev_attr_version.attr,
+	&dev_attr_version.attr.attr,
 	&dev_attr_fan.attr,
 	&dev_attr_kbd_backlight_mode.attr,
 	&dev_attr_kbd_type.attr,
-- 
2.43.0

[PATCH 6/6] scsi: Use device_show_string() helper for sysfs attributes

[Lukas Wunner]

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 <lukas@wunner.de>
---
 drivers/scsi/bfa/bfad_attr.c             | 28 ++++++------------------
 drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 11 ++--------
 drivers/scsi/mvsas/mv_init.c             | 10 ++-------
 drivers/scsi/qla2xxx/qla_attr.c          | 11 ++--------
 drivers/scsi/smartpqi/smartpqi_init.c    | 11 +++-------
 5 files changed, 16 insertions(+), 55 deletions(-)

diff --git a/drivers/scsi/bfa/bfad_attr.c b/drivers/scsi/bfa/bfad_attr.c
index e96e4b6df265..54bc1539e1e9 100644
--- a/drivers/scsi/bfa/bfad_attr.c
+++ b/drivers/scsi/bfa/bfad_attr.c
@@ -853,13 +853,6 @@ bfad_im_hw_version_show(struct device *dev, struct device_attribute *attr,
 	return sysfs_emit(buf, "%s\n", hw_ver);
 }
 
-static ssize_t
-bfad_im_drv_version_show(struct device *dev, struct device_attribute *attr,
-				char *buf)
-{
-	return sysfs_emit(buf, "%s\n", BFAD_DRIVER_VERSION);
-}
-
 static ssize_t
 bfad_im_optionrom_version_show(struct device *dev,
 			 struct device_attribute *attr, char *buf)
@@ -901,13 +894,6 @@ bfad_im_num_of_ports_show(struct device *dev, struct device_attribute *attr,
 			bfa_get_nports(&bfad->bfa));
 }
 
-static ssize_t
-bfad_im_drv_name_show(struct device *dev, struct device_attribute *attr,
-				char *buf)
-{
-	return sysfs_emit(buf, "%s\n", BFAD_DRIVER_NAME);
-}
-
 static ssize_t
 bfad_im_num_of_discovered_ports_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
@@ -944,15 +930,15 @@ static          DEVICE_ATTR(symbolic_name, S_IRUGO,
 				bfad_im_symbolic_name_show, NULL);
 static          DEVICE_ATTR(hardware_version, S_IRUGO,
 				bfad_im_hw_version_show, NULL);
-static          DEVICE_ATTR(driver_version, S_IRUGO,
-				bfad_im_drv_version_show, NULL);
+static		DEVICE_STRING_ATTR_RO(driver_version, S_IRUGO,
+				BFAD_DRIVER_VERSION);
 static          DEVICE_ATTR(option_rom_version, S_IRUGO,
 				bfad_im_optionrom_version_show, NULL);
 static          DEVICE_ATTR(firmware_version, S_IRUGO,
 				bfad_im_fw_version_show, NULL);
 static          DEVICE_ATTR(number_of_ports, S_IRUGO,
 				bfad_im_num_of_ports_show, NULL);
-static          DEVICE_ATTR(driver_name, S_IRUGO, bfad_im_drv_name_show, NULL);
+static		DEVICE_STRING_ATTR_RO(driver_name, S_IRUGO, BFAD_DRIVER_NAME);
 static          DEVICE_ATTR(number_of_discovered_ports, S_IRUGO,
 				bfad_im_num_of_discovered_ports_show, NULL);
 
@@ -963,11 +949,11 @@ static struct attribute *bfad_im_host_attrs[] = {
 	&dev_attr_node_name.attr,
 	&dev_attr_symbolic_name.attr,
 	&dev_attr_hardware_version.attr,
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_option_rom_version.attr,
 	&dev_attr_firmware_version.attr,
 	&dev_attr_number_of_ports.attr,
-	&dev_attr_driver_name.attr,
+	&dev_attr_driver_name.attr.attr,
 	&dev_attr_number_of_discovered_ports.attr,
 	NULL,
 };
@@ -988,11 +974,11 @@ static struct attribute *bfad_im_vport_attrs[] = {
 	&dev_attr_node_name.attr,
 	&dev_attr_symbolic_name.attr,
 	&dev_attr_hardware_version.attr,
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_option_rom_version.attr,
 	&dev_attr_firmware_version.attr,
 	&dev_attr_number_of_ports.attr,
-	&dev_attr_driver_name.attr,
+	&dev_attr_driver_name.attr.attr,
 	&dev_attr_number_of_discovered_ports.attr,
 	NULL,
 };
diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
index 68b99924ee4f..2fca17cf8b51 100644
--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
@@ -3613,12 +3613,6 @@ static void ibmvscsis_remove(struct vio_dev *vdev)
 	kfree(vscsi);
 }
 
-static ssize_t system_id_show(struct device *dev,
-			      struct device_attribute *attr, char *buf)
-{
-	return sysfs_emit(buf, "%s\n", system_id);
-}
-
 static ssize_t partition_number_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
@@ -3982,8 +3976,7 @@ static const struct target_core_fabric_ops ibmvscsis_ops = {
 
 static void ibmvscsis_dev_release(struct device *dev) {};
 
-static struct device_attribute dev_attr_system_id =
-	__ATTR(system_id, S_IRUGO, system_id_show, NULL);
+static DEVICE_STRING_ATTR_RO(system_id, S_IRUGO, system_id);
 
 static struct device_attribute dev_attr_partition_number =
 	__ATTR(partition_number, S_IRUGO, partition_number_show, NULL);
@@ -3992,7 +3985,7 @@ static struct device_attribute dev_attr_unit_address =
 	__ATTR(unit_address, S_IRUGO, unit_address_show, NULL);
 
 static struct attribute *ibmvscsis_dev_attrs[] = {
-	&dev_attr_system_id.attr,
+	&dev_attr_system_id.attr.attr,
 	&dev_attr_partition_number.attr,
 	&dev_attr_unit_address.attr,
 };
diff --git a/drivers/scsi/mvsas/mv_init.c b/drivers/scsi/mvsas/mv_init.c
index 43ebb331e216..2a25d574feb9 100644
--- a/drivers/scsi/mvsas/mv_init.c
+++ b/drivers/scsi/mvsas/mv_init.c
@@ -691,13 +691,7 @@ static struct pci_driver mvs_pci_driver = {
 	.remove		= mvs_pci_remove,
 };
 
-static ssize_t driver_version_show(struct device *cdev,
-				   struct device_attribute *attr, char *buffer)
-{
-	return sysfs_emit(buffer, "%s\n", DRV_VERSION);
-}
-
-static DEVICE_ATTR_RO(driver_version);
+static DEVICE_STRING_ATTR_RO(driver_version, 0444, DRV_VERSION);
 
 static ssize_t interrupt_coalescing_store(struct device *cdev,
 					  struct device_attribute *attr,
@@ -772,7 +766,7 @@ static void __exit mvs_exit(void)
 }
 
 static struct attribute *mvst_host_attrs[] = {
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_interrupt_coalescing.attr,
 	NULL,
 };
diff --git a/drivers/scsi/qla2xxx/qla_attr.c b/drivers/scsi/qla2xxx/qla_attr.c
index 44449c70a375..d4b420aef4a8 100644
--- a/drivers/scsi/qla2xxx/qla_attr.c
+++ b/drivers/scsi/qla2xxx/qla_attr.c
@@ -1067,13 +1067,6 @@ qla2x00_free_sysfs_attr(scsi_qla_host_t *vha, bool stop_beacon)
 
 /* Scsi_Host attributes. */
 
-static ssize_t
-qla2x00_driver_version_show(struct device *dev,
-			  struct device_attribute *attr, char *buf)
-{
-	return scnprintf(buf, PAGE_SIZE, "%s\n", qla2x00_version_str);
-}
-
 static ssize_t
 qla2x00_fw_version_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
@@ -2412,7 +2405,7 @@ qla2x00_dport_diagnostics_show(struct device *dev,
 static DEVICE_ATTR(dport_diagnostics, 0444,
 	   qla2x00_dport_diagnostics_show, NULL);
 
-static DEVICE_ATTR(driver_version, S_IRUGO, qla2x00_driver_version_show, NULL);
+static DEVICE_STRING_ATTR_RO(driver_version, S_IRUGO, qla2x00_version_str);
 static DEVICE_ATTR(fw_version, S_IRUGO, qla2x00_fw_version_show, NULL);
 static DEVICE_ATTR(serial_num, S_IRUGO, qla2x00_serial_num_show, NULL);
 static DEVICE_ATTR(isp_name, S_IRUGO, qla2x00_isp_name_show, NULL);
@@ -2478,7 +2471,7 @@ static DEVICE_ATTR(port_no, 0444, qla2x00_port_no_show, NULL);
 static DEVICE_ATTR(fw_attr, 0444, qla2x00_fw_attr_show, NULL);
 
 static struct attribute *qla2x00_host_attrs[] = {
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_fw_version.attr,
 	&dev_attr_serial_num.attr,
 	&dev_attr_isp_name.attr,
diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c
index 385180c98be4..f11cf590b2a9 100644
--- a/drivers/scsi/smartpqi/smartpqi_init.c
+++ b/drivers/scsi/smartpqi/smartpqi_init.c
@@ -6892,12 +6892,6 @@ static ssize_t pqi_firmware_version_show(struct device *dev,
 	return scnprintf(buffer, PAGE_SIZE, "%s\n", ctrl_info->firmware_version);
 }
 
-static ssize_t pqi_driver_version_show(struct device *dev,
-	struct device_attribute *attr, char *buffer)
-{
-	return scnprintf(buffer, PAGE_SIZE, "%s\n", DRIVER_VERSION BUILD_TIMESTAMP);
-}
-
 static ssize_t pqi_serial_number_show(struct device *dev,
 	struct device_attribute *attr, char *buffer)
 {
@@ -7066,7 +7060,8 @@ static ssize_t pqi_host_enable_r6_writes_store(struct device *dev,
 	return count;
 }
 
-static DEVICE_ATTR(driver_version, 0444, pqi_driver_version_show, NULL);
+static DEVICE_STRING_ATTR_RO(driver_version, 0444,
+	DRIVER_VERSION BUILD_TIMESTAMP);
 static DEVICE_ATTR(firmware_version, 0444, pqi_firmware_version_show, NULL);
 static DEVICE_ATTR(model, 0444, pqi_model_show, NULL);
 static DEVICE_ATTR(serial_number, 0444, pqi_serial_number_show, NULL);
@@ -7083,7 +7078,7 @@ static DEVICE_ATTR(enable_r6_writes, 0644,
 	pqi_host_enable_r6_writes_show, pqi_host_enable_r6_writes_store);
 
 static struct attribute *pqi_shost_attrs[] = {
-	&dev_attr_driver_version.attr,
+	&dev_attr_driver_version.attr.attr,
 	&dev_attr_firmware_version.attr,
 	&dev_attr_model.attr,
 	&dev_attr_serial_number.attr,
-- 
2.43.0

Re: [PATCH 2/6] hwmon: Use device_show_string() helper for sysfs attributes

[Guenter Roeck]

On Sat, Apr 20, 2024 at 10:00:02PM +0200, Lukas Wunner wrote:
> 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 <lukas@wunner.de>

Acked-by: Guenter Roeck <linux@roeck-us.net>

Guenter

Re: [PATCH 1/6] driver core: Add device_show_string() helper for sysfs attributes

[Michael Ellerman]

Lukas Wunner <lukas@wunner.de> writes:
> For drivers wishing to expose an unsigned long, int or bool at a static
> memory location in sysfs, the driver core provides ready-made helpers
> such as device_show_ulong() to be used as ->show() callback.
>
> Some drivers need to expose a string and so far they all provide their
> own ->show() implementation.  arch/powerpc/perf/hv-24x7.c went so far
> as to create a device_show_string() helper but kept it private.
>
> Make it public for reuse by other drivers.  The pattern seems to be
> sufficiently frequent to merit a public helper.
>
> Add a DEVICE_STRING_ATTR_RO() macro in line with the existing
> DEVICE_ULONG_ATTR() and similar macros to ease declaration of string
> attributes.
>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> ---
>  arch/powerpc/perf/hv-24x7.c | 10 ----------
>  drivers/base/core.c         |  9 +++++++++
>  include/linux/device.h      | 15 +++++++++++++++
>  3 files changed, 24 insertions(+), 10 deletions(-)

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

cheers

Re: [PATCH 5/6] platform/x86: Use device_show_string() helper for sysfs attributes

[Hans de Goede]

Hi,

On 4/20/24 10:00 PM, Lukas Wunner wrote:
> 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 <lukas@wunner.de>

Thanks, patch looks good to me:

Acked-by: Hans de Goede <hdegoede@redhat.com>

Feel free to upstream this though whatever git tree is convenient.

Regards,

Hans



> ---
>  drivers/platform/x86/asus-wmi.c      | 62 +++++++---------------------
>  drivers/platform/x86/thinkpad_acpi.c | 10 +----
>  drivers/platform/x86/toshiba_acpi.c  |  9 +---
>  3 files changed, 20 insertions(+), 61 deletions(-)
> 
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index 3f07bbf809ef..78d7579b2fdd 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -915,17 +915,12 @@ static ssize_t kbd_rgb_mode_store(struct device *dev,
>  }
>  static DEVICE_ATTR_WO(kbd_rgb_mode);
>  
> -static ssize_t kbd_rgb_mode_index_show(struct device *device,
> -						 struct device_attribute *attr,
> -						 char *buf)
> -{
> -	return sysfs_emit(buf, "%s\n", "cmd mode red green blue speed");
> -}
> -static DEVICE_ATTR_RO(kbd_rgb_mode_index);
> +static DEVICE_STRING_ATTR_RO(kbd_rgb_mode_index, 0444,
> +			     "cmd mode red green blue speed");
>  
>  static struct attribute *kbd_rgb_mode_attrs[] = {
>  	&dev_attr_kbd_rgb_mode.attr,
> -	&dev_attr_kbd_rgb_mode_index.attr,
> +	&dev_attr_kbd_rgb_mode_index.attr.attr,
>  	NULL,
>  };
>  
> @@ -967,17 +962,12 @@ static ssize_t kbd_rgb_state_store(struct device *dev,
>  }
>  static DEVICE_ATTR_WO(kbd_rgb_state);
>  
> -static ssize_t kbd_rgb_state_index_show(struct device *device,
> -						 struct device_attribute *attr,
> -						 char *buf)
> -{
> -	return sysfs_emit(buf, "%s\n", "cmd boot awake sleep keyboard");
> -}
> -static DEVICE_ATTR_RO(kbd_rgb_state_index);
> +static DEVICE_STRING_ATTR_RO(kbd_rgb_state_index, 0444,
> +			     "cmd boot awake sleep keyboard");
>  
>  static struct attribute *kbd_rgb_state_attrs[] = {
>  	&dev_attr_kbd_rgb_state.attr,
> -	&dev_attr_kbd_rgb_state_index.attr,
> +	&dev_attr_kbd_rgb_state_index.attr.attr,
>  	NULL,
>  };
>  
> @@ -2493,13 +2483,6 @@ static ssize_t pwm1_enable_store(struct device *dev,
>  	return count;
>  }
>  
> -static ssize_t fan1_label_show(struct device *dev,
> -					  struct device_attribute *attr,
> -					  char *buf)
> -{
> -	return sysfs_emit(buf, "%s\n", ASUS_FAN_DESC);
> -}
> -
>  static ssize_t asus_hwmon_temp1(struct device *dev,
>  				struct device_attribute *attr,
>  				char *buf)
> @@ -2534,13 +2517,6 @@ static ssize_t fan2_input_show(struct device *dev,
>  	return sysfs_emit(buf, "%d\n", value * 100);
>  }
>  
> -static ssize_t fan2_label_show(struct device *dev,
> -					  struct device_attribute *attr,
> -					  char *buf)
> -{
> -	return sysfs_emit(buf, "%s\n", ASUS_GPU_FAN_DESC);
> -}
> -
>  /* Middle/Center fan on modern ROG laptops */
>  static ssize_t fan3_input_show(struct device *dev,
>  					struct device_attribute *attr,
> @@ -2559,13 +2535,6 @@ static ssize_t fan3_input_show(struct device *dev,
>  	return sysfs_emit(buf, "%d\n", value * 100);
>  }
>  
> -static ssize_t fan3_label_show(struct device *dev,
> -					  struct device_attribute *attr,
> -					  char *buf)
> -{
> -	return sysfs_emit(buf, "%s\n", ASUS_MID_FAN_DESC);
> -}
> -
>  static ssize_t pwm2_enable_show(struct device *dev,
>  				struct device_attribute *attr,
>  				char *buf)
> @@ -2662,15 +2631,16 @@ static ssize_t pwm3_enable_store(struct device *dev,
>  static DEVICE_ATTR_RW(pwm1);
>  static DEVICE_ATTR_RW(pwm1_enable);
>  static DEVICE_ATTR_RO(fan1_input);
> -static DEVICE_ATTR_RO(fan1_label);
> +static DEVICE_STRING_ATTR_RO(fan1_label, 0444, ASUS_FAN_DESC);
> +
>  /* Fan2 - GPU fan */
>  static DEVICE_ATTR_RW(pwm2_enable);
>  static DEVICE_ATTR_RO(fan2_input);
> -static DEVICE_ATTR_RO(fan2_label);
> +static DEVICE_STRING_ATTR_RO(fan2_label, 0444, ASUS_GPU_FAN_DESC);
>  /* Fan3 - Middle/center fan */
>  static DEVICE_ATTR_RW(pwm3_enable);
>  static DEVICE_ATTR_RO(fan3_input);
> -static DEVICE_ATTR_RO(fan3_label);
> +static DEVICE_STRING_ATTR_RO(fan3_label, 0444, ASUS_MID_FAN_DESC);
>  
>  /* Temperature */
>  static DEVICE_ATTR(temp1_input, S_IRUGO, asus_hwmon_temp1, NULL);
> @@ -2681,11 +2651,11 @@ static struct attribute *hwmon_attributes[] = {
>  	&dev_attr_pwm2_enable.attr,
>  	&dev_attr_pwm3_enable.attr,
>  	&dev_attr_fan1_input.attr,
> -	&dev_attr_fan1_label.attr,
> +	&dev_attr_fan1_label.attr.attr,
>  	&dev_attr_fan2_input.attr,
> -	&dev_attr_fan2_label.attr,
> +	&dev_attr_fan2_label.attr.attr,
>  	&dev_attr_fan3_input.attr,
> -	&dev_attr_fan3_label.attr,
> +	&dev_attr_fan3_label.attr.attr,
>  
>  	&dev_attr_temp1_input.attr,
>  	NULL
> @@ -2702,17 +2672,17 @@ static umode_t asus_hwmon_sysfs_is_visible(struct kobject *kobj,
>  		if (asus->fan_type != FAN_TYPE_AGFN)
>  			return 0;
>  	} else if (attr == &dev_attr_fan1_input.attr
> -	    || attr == &dev_attr_fan1_label.attr
> +	    || attr == &dev_attr_fan1_label.attr.attr
>  	    || attr == &dev_attr_pwm1_enable.attr) {
>  		if (asus->fan_type == FAN_TYPE_NONE)
>  			return 0;
>  	} else if (attr == &dev_attr_fan2_input.attr
> -	    || attr == &dev_attr_fan2_label.attr
> +	    || attr == &dev_attr_fan2_label.attr.attr
>  	    || attr == &dev_attr_pwm2_enable.attr) {
>  		if (asus->gpu_fan_type == FAN_TYPE_NONE)
>  			return 0;
>  	} else if (attr == &dev_attr_fan3_input.attr
> -	    || attr == &dev_attr_fan3_label.attr
> +	    || attr == &dev_attr_fan3_label.attr.attr
>  	    || attr == &dev_attr_pwm3_enable.attr) {
>  		if (asus->mid_fan_type == FAN_TYPE_NONE)
>  			return 0;
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index 82429e59999d..47a64a213d14 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -10991,13 +10991,7 @@ static struct ibm_struct auxmac_data = {
>  	.name = "auxmac",
>  };
>  
> -static ssize_t auxmac_show(struct device *dev,
> -			   struct device_attribute *attr,
> -			   char *buf)
> -{
> -	return sysfs_emit(buf, "%s\n", auxmac);
> -}
> -static DEVICE_ATTR_RO(auxmac);
> +static DEVICE_STRING_ATTR_RO(auxmac, 0444, auxmac);
>  
>  static umode_t auxmac_attr_is_visible(struct kobject *kobj,
>  				      struct attribute *attr, int n)
> @@ -11006,7 +11000,7 @@ static umode_t auxmac_attr_is_visible(struct kobject *kobj,
>  }
>  
>  static struct attribute *auxmac_attributes[] = {
> -	&dev_attr_auxmac.attr,
> +	&dev_attr_auxmac.attr.attr,
>  	NULL
>  };
>  
> diff --git a/drivers/platform/x86/toshiba_acpi.c b/drivers/platform/x86/toshiba_acpi.c
> index 291f14ef6702..01cf60a015bf 100644
> --- a/drivers/platform/x86/toshiba_acpi.c
> +++ b/drivers/platform/x86/toshiba_acpi.c
> @@ -1814,12 +1814,7 @@ static DECLARE_WORK(kbd_bl_work, toshiba_acpi_kbd_bl_work);
>  /*
>   * Sysfs files
>   */
> -static ssize_t version_show(struct device *dev,
> -			    struct device_attribute *attr, char *buf)
> -{
> -	return sprintf(buf, "%s\n", TOSHIBA_ACPI_VERSION);
> -}
> -static DEVICE_ATTR_RO(version);
> +static DEVICE_STRING_ATTR_RO(version, 0444, TOSHIBA_ACPI_VERSION);
>  
>  static ssize_t fan_store(struct device *dev,
>  			 struct device_attribute *attr,
> @@ -2428,7 +2423,7 @@ static ssize_t cooling_method_store(struct device *dev,
>  static DEVICE_ATTR_RW(cooling_method);
>  
>  static struct attribute *toshiba_attributes[] = {
> -	&dev_attr_version.attr,
> +	&dev_attr_version.attr.attr,
>  	&dev_attr_fan.attr,
>  	&dev_attr_kbd_backlight_mode.attr,
>  	&dev_attr_kbd_type.attr,

Re: [PATCH 0/6] Deduplicate string exposure in sysfs

[Lukas Wunner]

Dear Greg,

On Sat, Apr 20, 2024 at 10:00:00PM +0200, Lukas Wunner wrote:
> Introduce a generic ->show() callback to expose a string as a device
> attribute in sysfs.  Deduplicate various identical callbacks across
> the tree.
> 
> Result:  Minus 216 LoC, minus 1576 bytes vmlinux size (x86_64 allyesconfig).
> 
> This is a byproduct of my upcoming PCI device authentication v2 patches.
> 
> 
> Lukas Wunner (6):
>   driver core: Add device_show_string() helper for sysfs attributes
>   hwmon: Use device_show_string() helper for sysfs attributes
>   IB/qib: Use device_show_string() helper for sysfs attributes
>   perf: Use device_show_string() helper for sysfs attributes
>   platform/x86: Use device_show_string() helper for sysfs attributes
>   scsi: Use device_show_string() helper for sysfs attributes

This series hasn't been applied to driver-core-next AFAICS and the
merge window is drawing closer.

So far only patches 1, 2 and 5 have been ack'ed by the respective
subsystem maintainers.  If the missing acks are the reason it hasn't
been applied, would it be possibe to apply only 1, 2 and 5?

I would then resubmit the other ones individually to the subsystem
maintainers in the next cycle.

Thanks!

Lukas

Re: [PATCH 0/6] Deduplicate string exposure in sysfs

[Greg Kroah-Hartman]

On Sat, May 04, 2024 at 04:31:42PM +0200, Lukas Wunner wrote:
> Dear Greg,
> 
> On Sat, Apr 20, 2024 at 10:00:00PM +0200, Lukas Wunner wrote:
> > Introduce a generic ->show() callback to expose a string as a device
> > attribute in sysfs.  Deduplicate various identical callbacks across
> > the tree.
> > 
> > Result:  Minus 216 LoC, minus 1576 bytes vmlinux size (x86_64 allyesconfig).
> > 
> > This is a byproduct of my upcoming PCI device authentication v2 patches.
> > 
> > 
> > Lukas Wunner (6):
> >   driver core: Add device_show_string() helper for sysfs attributes
> >   hwmon: Use device_show_string() helper for sysfs attributes
> >   IB/qib: Use device_show_string() helper for sysfs attributes
> >   perf: Use device_show_string() helper for sysfs attributes
> >   platform/x86: Use device_show_string() helper for sysfs attributes
> >   scsi: Use device_show_string() helper for sysfs attributes
> 
> This series hasn't been applied to driver-core-next AFAICS and the
> merge window is drawing closer.
> 
> So far only patches 1, 2 and 5 have been ack'ed by the respective
> subsystem maintainers.  If the missing acks are the reason it hasn't
> been applied, would it be possibe to apply only 1, 2 and 5?
> 
> I would then resubmit the other ones individually to the subsystem
> maintainers in the next cycle.

I'll just pick it up now, thanks!

greg k-h