[PATCH v2 3/3] driver core: Constify the signature of device_show/store_*()

["Thomas Weißschuh" <linux@weissschuh.net>]

Prepare for the constification of 'struct dev_ext_attribute' by changing
the signature of the standard callback functions.

Migrate the hv-24x7 driver in the same commit. It is the only user to
manually assign one of the standard callbacks.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 arch/powerpc/perf/hv-24x7.c |  2 +-
 drivers/base/core.c         | 30 +++++++++++++++---------------
 include/linux/device.h      | 14 +++++++-------
 3 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index b0eedf185960..3e094dc7d76b 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -462,7 +462,7 @@ static struct attribute *device_str_attr_create_(char *name, char *str)
 	attr->var = str;
 	attr->attr.attr.name = name;
 	attr->attr.attr.mode = 0444;
-	attr->attr.show = device_show_string;
+	attr->attr.show_const = device_show_string;
 
 	return &attr->attr.attr;
 }
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 4c0c373998a1..5daa88fa724a 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2517,13 +2517,13 @@ static const struct sysfs_ops dev_sysfs_ops = {
 	.store	= dev_attr_store,
 };
 
-#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
+#define to_ext_attr(x) container_of_const(x, struct dev_ext_attribute, attr)
 
 ssize_t device_store_ulong(struct device *dev,
-			   struct device_attribute *attr,
+			   const struct device_attribute *attr,
 			   const char *buf, size_t size)
 {
-	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	const struct dev_ext_attribute *ea = to_ext_attr(attr);
 	int ret;
 	unsigned long new;
 
@@ -2537,19 +2537,19 @@ ssize_t device_store_ulong(struct device *dev,
 EXPORT_SYMBOL_GPL(device_store_ulong);
 
 ssize_t device_show_ulong(struct device *dev,
-			  struct device_attribute *attr,
+			  const struct device_attribute *attr,
 			  char *buf)
 {
-	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	const struct dev_ext_attribute *ea = to_ext_attr(attr);
 	return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var));
 }
 EXPORT_SYMBOL_GPL(device_show_ulong);
 
 ssize_t device_store_int(struct device *dev,
-			 struct device_attribute *attr,
+			 const struct device_attribute *attr,
 			 const char *buf, size_t size)
 {
-	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	const struct dev_ext_attribute *ea = to_ext_attr(attr);
 	int ret;
 	long new;
 
@@ -2566,19 +2566,19 @@ ssize_t device_store_int(struct device *dev,
 EXPORT_SYMBOL_GPL(device_store_int);
 
 ssize_t device_show_int(struct device *dev,
-			struct device_attribute *attr,
+			const struct device_attribute *attr,
 			char *buf)
 {
-	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	const struct dev_ext_attribute *ea = to_ext_attr(attr);
 
 	return sysfs_emit(buf, "%d\n", *(int *)(ea->var));
 }
 EXPORT_SYMBOL_GPL(device_show_int);
 
-ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
+ssize_t device_store_bool(struct device *dev, const struct device_attribute *attr,
 			  const char *buf, size_t size)
 {
-	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	const struct dev_ext_attribute *ea = to_ext_attr(attr);
 
 	if (kstrtobool(buf, ea->var) < 0)
 		return -EINVAL;
@@ -2587,19 +2587,19 @@ ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
 }
 EXPORT_SYMBOL_GPL(device_store_bool);
 
-ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
+ssize_t device_show_bool(struct device *dev, const struct device_attribute *attr,
 			 char *buf)
 {
-	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	const struct dev_ext_attribute *ea = to_ext_attr(attr);
 
 	return sysfs_emit(buf, "%d\n", *(bool *)(ea->var));
 }
 EXPORT_SYMBOL_GPL(device_show_bool);
 
 ssize_t device_show_string(struct device *dev,
-			   struct device_attribute *attr, char *buf)
+			   const struct device_attribute *attr, char *buf)
 {
-	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	const struct dev_ext_attribute *ea = to_ext_attr(attr);
 
 	return sysfs_emit(buf, "%s\n", (char *)ea->var);
 }
diff --git a/include/linux/device.h b/include/linux/device.h
index aee79fd6b32b..90cdd77458bb 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -129,19 +129,19 @@ struct dev_ext_attribute {
 	void *var;
 };
 
-ssize_t device_show_ulong(struct device *dev, struct device_attribute *attr,
+ssize_t device_show_ulong(struct device *dev, const struct device_attribute *attr,
 			  char *buf);
-ssize_t device_store_ulong(struct device *dev, struct device_attribute *attr,
+ssize_t device_store_ulong(struct device *dev, const struct device_attribute *attr,
 			   const char *buf, size_t count);
-ssize_t device_show_int(struct device *dev, struct device_attribute *attr,
+ssize_t device_show_int(struct device *dev, const struct device_attribute *attr,
 			char *buf);
-ssize_t device_store_int(struct device *dev, struct device_attribute *attr,
+ssize_t device_store_int(struct device *dev, const struct device_attribute *attr,
 			 const char *buf, size_t count);
-ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
+ssize_t device_show_bool(struct device *dev, const struct device_attribute *attr,
 			char *buf);
-ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
+ssize_t device_store_bool(struct device *dev, const struct device_attribute *attr,
 			 const char *buf, size_t count);
-ssize_t device_show_string(struct device *dev, struct device_attribute *attr,
+ssize_t device_show_string(struct device *dev, const struct device_attribute *attr,
 			   char *buf);
 
 typedef ssize_t __device_show_handler_const(struct device *dev, const struct device_attribute *attr,

-- 
2.55.0