[PATCH 1/3] fpga: bridge: make fpga_bridge_class a static const structure

[PATCH 1/3] fpga: bridge: make fpga_bridge_class a static const structure

[Ivan Orlov]

Now that the driver core allows for struct class to be in read-only
memory, move the fpga_bridge_class structure to be declared at build
time placing it into read-only memory, instead of having to be
dynamically allocated at boot time.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
---
 drivers/fpga/fpga-bridge.c | 106 ++++++++++++++++++-------------------
 1 file changed, 52 insertions(+), 54 deletions(-)

diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
index a6c25dee9cc1..6e38ddaf16cf 100644
--- a/drivers/fpga/fpga-bridge.c
+++ b/drivers/fpga/fpga-bridge.c
@@ -14,7 +14,6 @@
 #include <linux/spinlock.h>
 
 static DEFINE_IDA(fpga_bridge_ida);
-static struct class *fpga_bridge_class;
 
 /* Lock for adding/removing bridges to linked lists*/
 static DEFINE_SPINLOCK(bridge_list_lock);
@@ -84,6 +83,53 @@ static struct fpga_bridge *__fpga_bridge_get(struct device *dev,
 	return ERR_PTR(ret);
 }
 
+static ssize_t name_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct fpga_bridge *bridge = to_fpga_bridge(dev);
+
+	return sprintf(buf, "%s\n", bridge->name);
+}
+
+static ssize_t state_show(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct fpga_bridge *bridge = to_fpga_bridge(dev);
+	int state = 1;
+
+	if (bridge->br_ops && bridge->br_ops->enable_show) {
+		state = bridge->br_ops->enable_show(bridge);
+		if (state < 0)
+			return state;
+	}
+
+	return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
+}
+
+static DEVICE_ATTR_RO(name);
+static DEVICE_ATTR_RO(state);
+
+static struct attribute *fpga_bridge_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_state.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(fpga_bridge);
+
+static void fpga_bridge_dev_release(struct device *dev)
+{
+	struct fpga_bridge *bridge = to_fpga_bridge(dev);
+
+	ida_free(&fpga_bridge_ida, bridge->dev.id);
+	kfree(bridge);
+}
+
+static const struct class fpga_bridge_class = {
+	.name = "fpga_bridge",
+	.dev_groups = fpga_bridge_groups,
+	.dev_release = fpga_bridge_dev_release,
+};
+
 /**
  * of_fpga_bridge_get - get an exclusive reference to an fpga bridge
  *
@@ -99,7 +145,7 @@ struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
 {
 	struct device *dev;
 
-	dev = class_find_device_by_of_node(fpga_bridge_class, np);
+	dev = class_find_device_by_of_node(&fpga_bridge_class, np);
 	if (!dev)
 		return ERR_PTR(-ENODEV);
 
@@ -126,7 +172,7 @@ struct fpga_bridge *fpga_bridge_get(struct device *dev,
 {
 	struct device *bridge_dev;
 
-	bridge_dev = class_find_device(fpga_bridge_class, NULL, dev,
+	bridge_dev = class_find_device(&fpga_bridge_class, NULL, dev,
 				       fpga_bridge_dev_match);
 	if (!bridge_dev)
 		return ERR_PTR(-ENODEV);
@@ -281,39 +327,6 @@ int fpga_bridge_get_to_list(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
 
-static ssize_t name_show(struct device *dev,
-			 struct device_attribute *attr, char *buf)
-{
-	struct fpga_bridge *bridge = to_fpga_bridge(dev);
-
-	return sprintf(buf, "%s\n", bridge->name);
-}
-
-static ssize_t state_show(struct device *dev,
-			  struct device_attribute *attr, char *buf)
-{
-	struct fpga_bridge *bridge = to_fpga_bridge(dev);
-	int state = 1;
-
-	if (bridge->br_ops && bridge->br_ops->enable_show) {
-		state = bridge->br_ops->enable_show(bridge);
-		if (state < 0)
-			return state;
-	}
-
-	return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
-}
-
-static DEVICE_ATTR_RO(name);
-static DEVICE_ATTR_RO(state);
-
-static struct attribute *fpga_bridge_attrs[] = {
-	&dev_attr_name.attr,
-	&dev_attr_state.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(fpga_bridge);
-
 /**
  * fpga_bridge_register - create and register an FPGA Bridge device
  * @parent:	FPGA bridge device from pdev
@@ -359,7 +372,7 @@ fpga_bridge_register(struct device *parent, const char *name,
 	bridge->priv = priv;
 
 	bridge->dev.groups = br_ops->groups;
-	bridge->dev.class = fpga_bridge_class;
+	bridge->dev.class = &fpga_bridge_class;
 	bridge->dev.parent = parent;
 	bridge->dev.of_node = parent->of_node;
 	bridge->dev.id = id;
@@ -407,29 +420,14 @@ void fpga_bridge_unregister(struct fpga_bridge *bridge)
 }
 EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
 
-static void fpga_bridge_dev_release(struct device *dev)
-{
-	struct fpga_bridge *bridge = to_fpga_bridge(dev);
-
-	ida_free(&fpga_bridge_ida, bridge->dev.id);
-	kfree(bridge);
-}
-
 static int __init fpga_bridge_dev_init(void)
 {
-	fpga_bridge_class = class_create("fpga_bridge");
-	if (IS_ERR(fpga_bridge_class))
-		return PTR_ERR(fpga_bridge_class);
-
-	fpga_bridge_class->dev_groups = fpga_bridge_groups;
-	fpga_bridge_class->dev_release = fpga_bridge_dev_release;
-
-	return 0;
+	return class_register(&fpga_bridge_class);
 }
 
 static void __exit fpga_bridge_dev_exit(void)
 {
-	class_destroy(fpga_bridge_class);
+	class_unregister(&fpga_bridge_class);
 	ida_destroy(&fpga_bridge_ida);
 }
 
-- 
2.34.1

[PATCH 2/3] fpga: fpga-mgr: make fpga_mgr_class a static const structure

[Ivan Orlov]

Now that the driver core allows for struct class to be in read-only
memory, move the fpga_mgr_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
---
 drivers/fpga/fpga-mgr.c | 40 +++++++++++++++++++---------------------
 1 file changed, 19 insertions(+), 21 deletions(-)

diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
index eb583f86a0b9..cd5b7371495b 100644
--- a/drivers/fpga/fpga-mgr.c
+++ b/drivers/fpga/fpga-mgr.c
@@ -19,7 +19,6 @@
 #include <linux/highmem.h>
 
 static DEFINE_IDA(fpga_mgr_ida);
-static struct class *fpga_mgr_class;
 
 struct fpga_mgr_devres {
 	struct fpga_manager *mgr;
@@ -664,6 +663,20 @@ static struct attribute *fpga_mgr_attrs[] = {
 };
 ATTRIBUTE_GROUPS(fpga_mgr);
 
+static void fpga_mgr_dev_release(struct device *dev)
+{
+	struct fpga_manager *mgr = to_fpga_manager(dev);
+
+	ida_free(&fpga_mgr_ida, mgr->dev.id);
+	kfree(mgr);
+}
+
+static const struct class fpga_mgr_class = {
+	.name = "fpga_manager",
+	.dev_groups = fpga_mgr_groups,
+	.dev_release = fpga_mgr_dev_release,
+};
+
 static struct fpga_manager *__fpga_mgr_get(struct device *dev)
 {
 	struct fpga_manager *mgr;
@@ -693,7 +706,7 @@ static int fpga_mgr_dev_match(struct device *dev, const void *data)
  */
 struct fpga_manager *fpga_mgr_get(struct device *dev)
 {
-	struct device *mgr_dev = class_find_device(fpga_mgr_class, NULL, dev,
+	struct device *mgr_dev = class_find_device(&fpga_mgr_class, NULL, dev,
 						   fpga_mgr_dev_match);
 	if (!mgr_dev)
 		return ERR_PTR(-ENODEV);
@@ -713,7 +726,7 @@ struct fpga_manager *of_fpga_mgr_get(struct device_node *node)
 {
 	struct device *dev;
 
-	dev = class_find_device_by_of_node(fpga_mgr_class, node);
+	dev = class_find_device_by_of_node(&fpga_mgr_class, node);
 	if (!dev)
 		return ERR_PTR(-ENODEV);
 
@@ -809,7 +822,7 @@ fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *in
 	mgr->priv = info->priv;
 	mgr->compat_id = info->compat_id;
 
-	mgr->dev.class = fpga_mgr_class;
+	mgr->dev.class = &fpga_mgr_class;
 	mgr->dev.groups = mops->groups;
 	mgr->dev.parent = parent;
 	mgr->dev.of_node = parent->of_node;
@@ -959,31 +972,16 @@ devm_fpga_mgr_register(struct device *parent, const char *name,
 }
 EXPORT_SYMBOL_GPL(devm_fpga_mgr_register);
 
-static void fpga_mgr_dev_release(struct device *dev)
-{
-	struct fpga_manager *mgr = to_fpga_manager(dev);
-
-	ida_free(&fpga_mgr_ida, mgr->dev.id);
-	kfree(mgr);
-}
-
 static int __init fpga_mgr_class_init(void)
 {
 	pr_info("FPGA manager framework\n");
 
-	fpga_mgr_class = class_create("fpga_manager");
-	if (IS_ERR(fpga_mgr_class))
-		return PTR_ERR(fpga_mgr_class);
-
-	fpga_mgr_class->dev_groups = fpga_mgr_groups;
-	fpga_mgr_class->dev_release = fpga_mgr_dev_release;
-
-	return 0;
+	return class_register(&fpga_mgr_class);
 }
 
 static void __exit fpga_mgr_class_exit(void)
 {
-	class_destroy(fpga_mgr_class);
+	class_unregister(&fpga_mgr_class);
 	ida_destroy(&fpga_mgr_ida);
 }
 
-- 
2.34.1

[PATCH 3/3] fpga: region: make fpga_region_class a static const structure

[Ivan Orlov]

Now that the driver core allows for struct class to be in read-only
memory, move the fpga_region_class structure to be declared at build
time placing it into read-only memory, instead of having to be
dynamically allocated at boot time.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
---
 drivers/fpga/fpga-region.c | 64 ++++++++++++++++++--------------------
 1 file changed, 31 insertions(+), 33 deletions(-)

diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
index ccf6fdab1360..01cf4c2f83d1 100644
--- a/drivers/fpga/fpga-region.c
+++ b/drivers/fpga/fpga-region.c
@@ -16,21 +16,6 @@
 #include <linux/spinlock.h>
 
 static DEFINE_IDA(fpga_region_ida);
-static struct class *fpga_region_class;
-
-struct fpga_region *
-fpga_region_class_find(struct device *start, const void *data,
-		       int (*match)(struct device *, const void *))
-{
-	struct device *dev;
-
-	dev = class_find_device(fpga_region_class, start, data, match);
-	if (!dev)
-		return NULL;
-
-	return to_fpga_region(dev);
-}
-EXPORT_SYMBOL_GPL(fpga_region_class_find);
 
 /**
  * fpga_region_get - get an exclusive reference to an fpga region
@@ -179,6 +164,34 @@ static struct attribute *fpga_region_attrs[] = {
 };
 ATTRIBUTE_GROUPS(fpga_region);
 
+static void fpga_region_dev_release(struct device *dev)
+{
+	struct fpga_region *region = to_fpga_region(dev);
+
+	ida_free(&fpga_region_ida, region->dev.id);
+	kfree(region);
+}
+
+static const struct class fpga_region_class = {
+	.name = "fpga_region",
+	.dev_groups = fpga_region_groups,
+	.dev_release = fpga_region_dev_release,
+};
+
+struct fpga_region *
+fpga_region_class_find(struct device *start, const void *data,
+		       int (*match)(struct device *, const void *))
+{
+	struct device *dev;
+
+	dev = class_find_device(&fpga_region_class, start, data, match);
+	if (!dev)
+		return NULL;
+
+	return to_fpga_region(dev);
+}
+EXPORT_SYMBOL_GPL(fpga_region_class_find);
+
 /**
  * fpga_region_register_full - create and register an FPGA Region device
  * @parent: device parent
@@ -216,7 +229,7 @@ fpga_region_register_full(struct device *parent, const struct fpga_region_info *
 	mutex_init(&region->mutex);
 	INIT_LIST_HEAD(&region->bridge_list);
 
-	region->dev.class = fpga_region_class;
+	region->dev.class = &fpga_region_class;
 	region->dev.parent = parent;
 	region->dev.of_node = parent->of_node;
 	region->dev.id = id;
@@ -279,33 +292,18 @@ void fpga_region_unregister(struct fpga_region *region)
 }
 EXPORT_SYMBOL_GPL(fpga_region_unregister);
 
-static void fpga_region_dev_release(struct device *dev)
-{
-	struct fpga_region *region = to_fpga_region(dev);
-
-	ida_free(&fpga_region_ida, region->dev.id);
-	kfree(region);
-}
-
 /**
  * fpga_region_init - init function for fpga_region class
  * Creates the fpga_region class and registers a reconfig notifier.
  */
 static int __init fpga_region_init(void)
 {
-	fpga_region_class = class_create("fpga_region");
-	if (IS_ERR(fpga_region_class))
-		return PTR_ERR(fpga_region_class);
-
-	fpga_region_class->dev_groups = fpga_region_groups;
-	fpga_region_class->dev_release = fpga_region_dev_release;
-
-	return 0;
+	return class_register(&fpga_region_class);
 }
 
 static void __exit fpga_region_exit(void)
 {
-	class_destroy(fpga_region_class);
+	class_unregister(&fpga_region_class);
 	ida_destroy(&fpga_region_ida);
 }
 
-- 
2.34.1

Re: [PATCH 1/3] fpga: bridge: make fpga_bridge_class a static const structure

[Xu Yilun]

On 2023-08-10 at 21:22:08 +0400, Ivan Orlov wrote:
> Now that the driver core allows for struct class to be in read-only
> memory, move the fpga_bridge_class structure to be declared at build
> time placing it into read-only memory, instead of having to be
> dynamically allocated at boot time.
> 
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
> ---
>  drivers/fpga/fpga-bridge.c | 106 ++++++++++++++++++-------------------
>  1 file changed, 52 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
> index a6c25dee9cc1..6e38ddaf16cf 100644
> --- a/drivers/fpga/fpga-bridge.c
> +++ b/drivers/fpga/fpga-bridge.c
> @@ -14,7 +14,6 @@
>  #include <linux/spinlock.h>
>  
>  static DEFINE_IDA(fpga_bridge_ida);
> -static struct class *fpga_bridge_class;

Could we still use the forward declaration, to avoid moving too
much code block.

>  
>  /* Lock for adding/removing bridges to linked lists*/
>  static DEFINE_SPINLOCK(bridge_list_lock);
> @@ -84,6 +83,53 @@ static struct fpga_bridge *__fpga_bridge_get(struct device *dev,
>  	return ERR_PTR(ret);
>  }
>  
> +static ssize_t name_show(struct device *dev,
> +			 struct device_attribute *attr, char *buf)
> +{
> +	struct fpga_bridge *bridge = to_fpga_bridge(dev);
> +
> +	return sprintf(buf, "%s\n", bridge->name);
> +}
> +
> +static ssize_t state_show(struct device *dev,
> +			  struct device_attribute *attr, char *buf)
> +{
> +	struct fpga_bridge *bridge = to_fpga_bridge(dev);
> +	int state = 1;
> +
> +	if (bridge->br_ops && bridge->br_ops->enable_show) {
> +		state = bridge->br_ops->enable_show(bridge);
> +		if (state < 0)
> +			return state;
> +	}
> +
> +	return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
> +}
> +
> +static DEVICE_ATTR_RO(name);
> +static DEVICE_ATTR_RO(state);
> +
> +static struct attribute *fpga_bridge_attrs[] = {
> +	&dev_attr_name.attr,
> +	&dev_attr_state.attr,
> +	NULL,
> +};
> +ATTRIBUTE_GROUPS(fpga_bridge);
> +
> +static void fpga_bridge_dev_release(struct device *dev)
> +{
> +	struct fpga_bridge *bridge = to_fpga_bridge(dev);
> +
> +	ida_free(&fpga_bridge_ida, bridge->dev.id);
> +	kfree(bridge);
> +}
> +
> +static const struct class fpga_bridge_class = {
> +	.name = "fpga_bridge",
> +	.dev_groups = fpga_bridge_groups,
> +	.dev_release = fpga_bridge_dev_release,
> +};

Insert them between __fpga_bridge_get() and of_fpga_bridge_get() is not
preferred. See below comments.

> +
>  /**
>   * of_fpga_bridge_get - get an exclusive reference to an fpga bridge
>   *
> @@ -99,7 +145,7 @@ struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
>  {
>  	struct device *dev;
>  
> -	dev = class_find_device_by_of_node(fpga_bridge_class, np);
> +	dev = class_find_device_by_of_node(&fpga_bridge_class, np);
>  	if (!dev)
>  		return ERR_PTR(-ENODEV);
>  
> @@ -126,7 +172,7 @@ struct fpga_bridge *fpga_bridge_get(struct device *dev,
>  {
>  	struct device *bridge_dev;
>  
> -	bridge_dev = class_find_device(fpga_bridge_class, NULL, dev,
> +	bridge_dev = class_find_device(&fpga_bridge_class, NULL, dev,
>  				       fpga_bridge_dev_match);
>  	if (!bridge_dev)
>  		return ERR_PTR(-ENODEV);
> @@ -281,39 +327,6 @@ int fpga_bridge_get_to_list(struct device *dev,
>  }
>  EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
>  
> -static ssize_t name_show(struct device *dev,
> -			 struct device_attribute *attr, char *buf)
> -{
> -	struct fpga_bridge *bridge = to_fpga_bridge(dev);
> -
> -	return sprintf(buf, "%s\n", bridge->name);
> -}
> -
> -static ssize_t state_show(struct device *dev,
> -			  struct device_attribute *attr, char *buf)
> -{
> -	struct fpga_bridge *bridge = to_fpga_bridge(dev);
> -	int state = 1;
> -
> -	if (bridge->br_ops && bridge->br_ops->enable_show) {
> -		state = bridge->br_ops->enable_show(bridge);
> -		if (state < 0)
> -			return state;
> -	}
> -
> -	return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
> -}
> -
> -static DEVICE_ATTR_RO(name);
> -static DEVICE_ATTR_RO(state);
> -
> -static struct attribute *fpga_bridge_attrs[] = {
> -	&dev_attr_name.attr,
> -	&dev_attr_state.attr,
> -	NULL,
> -};
> -ATTRIBUTE_GROUPS(fpga_bridge);
> -
>  /**
>   * fpga_bridge_register - create and register an FPGA Bridge device
>   * @parent:	FPGA bridge device from pdev
> @@ -359,7 +372,7 @@ fpga_bridge_register(struct device *parent, const char *name,
>  	bridge->priv = priv;
>  
>  	bridge->dev.groups = br_ops->groups;
> -	bridge->dev.class = fpga_bridge_class;
> +	bridge->dev.class = &fpga_bridge_class;
>  	bridge->dev.parent = parent;
>  	bridge->dev.of_node = parent->of_node;
>  	bridge->dev.id = id;
> @@ -407,29 +420,14 @@ void fpga_bridge_unregister(struct fpga_bridge *bridge)
>  }
>  EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
>  
> -static void fpga_bridge_dev_release(struct device *dev)
> -{
> -	struct fpga_bridge *bridge = to_fpga_bridge(dev);
> -
> -	ida_free(&fpga_bridge_ida, bridge->dev.id);
> -	kfree(bridge);
> -}
> -

How about put the fpga_bridge_class definition here?

Thanks,
Yilun

>  static int __init fpga_bridge_dev_init(void)
>  {
> -	fpga_bridge_class = class_create("fpga_bridge");
> -	if (IS_ERR(fpga_bridge_class))
> -		return PTR_ERR(fpga_bridge_class);
> -
> -	fpga_bridge_class->dev_groups = fpga_bridge_groups;
> -	fpga_bridge_class->dev_release = fpga_bridge_dev_release;
> -
> -	return 0;
> +	return class_register(&fpga_bridge_class);
>  }
>  
>  static void __exit fpga_bridge_dev_exit(void)
>  {
> -	class_destroy(fpga_bridge_class);
> +	class_unregister(&fpga_bridge_class);
>  	ida_destroy(&fpga_bridge_ida);
>  }
>  
> -- 
> 2.34.1
> 

Re: [PATCH 2/3] fpga: fpga-mgr: make fpga_mgr_class a static const structure

[Xu Yilun]

On 2023-08-10 at 21:22:09 +0400, Ivan Orlov wrote:
> Now that the driver core allows for struct class to be in read-only
> memory, move the fpga_mgr_class structure to be declared at build time
> placing it into read-only memory, instead of having to be dynamically
> allocated at boot time.
> 
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
> ---
>  drivers/fpga/fpga-mgr.c | 40 +++++++++++++++++++---------------------
>  1 file changed, 19 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
> index eb583f86a0b9..cd5b7371495b 100644
> --- a/drivers/fpga/fpga-mgr.c
> +++ b/drivers/fpga/fpga-mgr.c
> @@ -19,7 +19,6 @@
>  #include <linux/highmem.h>
>  
>  static DEFINE_IDA(fpga_mgr_ida);
> -static struct class *fpga_mgr_class;
>  
>  struct fpga_mgr_devres {
>  	struct fpga_manager *mgr;
> @@ -664,6 +663,20 @@ static struct attribute *fpga_mgr_attrs[] = {
>  };
>  ATTRIBUTE_GROUPS(fpga_mgr);
>  
> +static void fpga_mgr_dev_release(struct device *dev)
> +{
> +	struct fpga_manager *mgr = to_fpga_manager(dev);
> +
> +	ida_free(&fpga_mgr_ida, mgr->dev.id);
> +	kfree(mgr);
> +}
> +
> +static const struct class fpga_mgr_class = {
> +	.name = "fpga_manager",
> +	.dev_groups = fpga_mgr_groups,
> +	.dev_release = fpga_mgr_dev_release,
> +};

Same concern as fpga_bridge, keep the forward declaration and put the
definiton below.

Thanks,
Yilun

> +
>  static struct fpga_manager *__fpga_mgr_get(struct device *dev)
>  {
>  	struct fpga_manager *mgr;
> @@ -693,7 +706,7 @@ static int fpga_mgr_dev_match(struct device *dev, const void *data)
>   */
>  struct fpga_manager *fpga_mgr_get(struct device *dev)
>  {
> -	struct device *mgr_dev = class_find_device(fpga_mgr_class, NULL, dev,
> +	struct device *mgr_dev = class_find_device(&fpga_mgr_class, NULL, dev,
>  						   fpga_mgr_dev_match);
>  	if (!mgr_dev)
>  		return ERR_PTR(-ENODEV);
> @@ -713,7 +726,7 @@ struct fpga_manager *of_fpga_mgr_get(struct device_node *node)
>  {
>  	struct device *dev;
>  
> -	dev = class_find_device_by_of_node(fpga_mgr_class, node);
> +	dev = class_find_device_by_of_node(&fpga_mgr_class, node);
>  	if (!dev)
>  		return ERR_PTR(-ENODEV);
>  
> @@ -809,7 +822,7 @@ fpga_mgr_register_full(struct device *parent, const struct fpga_manager_info *in
>  	mgr->priv = info->priv;
>  	mgr->compat_id = info->compat_id;
>  
> -	mgr->dev.class = fpga_mgr_class;
> +	mgr->dev.class = &fpga_mgr_class;
>  	mgr->dev.groups = mops->groups;
>  	mgr->dev.parent = parent;
>  	mgr->dev.of_node = parent->of_node;
> @@ -959,31 +972,16 @@ devm_fpga_mgr_register(struct device *parent, const char *name,
>  }
>  EXPORT_SYMBOL_GPL(devm_fpga_mgr_register);
>  
> -static void fpga_mgr_dev_release(struct device *dev)
> -{
> -	struct fpga_manager *mgr = to_fpga_manager(dev);
> -
> -	ida_free(&fpga_mgr_ida, mgr->dev.id);
> -	kfree(mgr);
> -}
> -
>  static int __init fpga_mgr_class_init(void)
>  {
>  	pr_info("FPGA manager framework\n");
>  
> -	fpga_mgr_class = class_create("fpga_manager");
> -	if (IS_ERR(fpga_mgr_class))
> -		return PTR_ERR(fpga_mgr_class);
> -
> -	fpga_mgr_class->dev_groups = fpga_mgr_groups;
> -	fpga_mgr_class->dev_release = fpga_mgr_dev_release;
> -
> -	return 0;
> +	return class_register(&fpga_mgr_class);
>  }
>  
>  static void __exit fpga_mgr_class_exit(void)
>  {
> -	class_destroy(fpga_mgr_class);
> +	class_unregister(&fpga_mgr_class);
>  	ida_destroy(&fpga_mgr_ida);
>  }
>  
> -- 
> 2.34.1
> 

Re: [PATCH 3/3] fpga: region: make fpga_region_class a static const structure

[Xu Yilun]

On 2023-08-10 at 21:22:10 +0400, Ivan Orlov wrote:
> Now that the driver core allows for struct class to be in read-only
> memory, move the fpga_region_class structure to be declared at build
> time placing it into read-only memory, instead of having to be
> dynamically allocated at boot time.
> 
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
> ---
>  drivers/fpga/fpga-region.c | 64 ++++++++++++++++++--------------------
>  1 file changed, 31 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index ccf6fdab1360..01cf4c2f83d1 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -16,21 +16,6 @@
>  #include <linux/spinlock.h>
>  
>  static DEFINE_IDA(fpga_region_ida);
> -static struct class *fpga_region_class;
> -
> -struct fpga_region *
> -fpga_region_class_find(struct device *start, const void *data,
> -		       int (*match)(struct device *, const void *))
> -{
> -	struct device *dev;
> -
> -	dev = class_find_device(fpga_region_class, start, data, match);
> -	if (!dev)
> -		return NULL;
> -
> -	return to_fpga_region(dev);
> -}
> -EXPORT_SYMBOL_GPL(fpga_region_class_find);
>  
>  /**
>   * fpga_region_get - get an exclusive reference to an fpga region
> @@ -179,6 +164,34 @@ static struct attribute *fpga_region_attrs[] = {
>  };
>  ATTRIBUTE_GROUPS(fpga_region);
>  
> +static void fpga_region_dev_release(struct device *dev)
> +{
> +	struct fpga_region *region = to_fpga_region(dev);
> +
> +	ida_free(&fpga_region_ida, region->dev.id);
> +	kfree(region);
> +}
> +
> +static const struct class fpga_region_class = {
> +	.name = "fpga_region",
> +	.dev_groups = fpga_region_groups,
> +	.dev_release = fpga_region_dev_release,
> +};

Same concern as previous patches。

Thanks,
Yilun

> +
> +struct fpga_region *
> +fpga_region_class_find(struct device *start, const void *data,
> +		       int (*match)(struct device *, const void *))
> +{
> +	struct device *dev;
> +
> +	dev = class_find_device(&fpga_region_class, start, data, match);
> +	if (!dev)
> +		return NULL;
> +
> +	return to_fpga_region(dev);
> +}
> +EXPORT_SYMBOL_GPL(fpga_region_class_find);
> +
>  /**
>   * fpga_region_register_full - create and register an FPGA Region device
>   * @parent: device parent
> @@ -216,7 +229,7 @@ fpga_region_register_full(struct device *parent, const struct fpga_region_info *
>  	mutex_init(&region->mutex);
>  	INIT_LIST_HEAD(&region->bridge_list);
>  
> -	region->dev.class = fpga_region_class;
> +	region->dev.class = &fpga_region_class;
>  	region->dev.parent = parent;
>  	region->dev.of_node = parent->of_node;
>  	region->dev.id = id;
> @@ -279,33 +292,18 @@ void fpga_region_unregister(struct fpga_region *region)
>  }
>  EXPORT_SYMBOL_GPL(fpga_region_unregister);
>  
> -static void fpga_region_dev_release(struct device *dev)
> -{
> -	struct fpga_region *region = to_fpga_region(dev);
> -
> -	ida_free(&fpga_region_ida, region->dev.id);
> -	kfree(region);
> -}
> -
>  /**
>   * fpga_region_init - init function for fpga_region class
>   * Creates the fpga_region class and registers a reconfig notifier.
>   */
>  static int __init fpga_region_init(void)
>  {
> -	fpga_region_class = class_create("fpga_region");
> -	if (IS_ERR(fpga_region_class))
> -		return PTR_ERR(fpga_region_class);
> -
> -	fpga_region_class->dev_groups = fpga_region_groups;
> -	fpga_region_class->dev_release = fpga_region_dev_release;
> -
> -	return 0;
> +	return class_register(&fpga_region_class);
>  }
>  
>  static void __exit fpga_region_exit(void)
>  {
> -	class_destroy(fpga_region_class);
> +	class_unregister(&fpga_region_class);
>  	ida_destroy(&fpga_region_ida);
>  }
>  
> -- 
> 2.34.1
> 

Re: [PATCH 1/3] fpga: bridge: make fpga_bridge_class a static const structure

[Ivan Orlov]

On 8/11/23 07:09, Xu Yilun wrote:
> On 2023-08-10 at 21:22:08 +0400, Ivan Orlov wrote:
>> Now that the driver core allows for struct class to be in read-only
>> memory, move the fpga_bridge_class structure to be declared at build
>> time placing it into read-only memory, instead of having to be
>> dynamically allocated at boot time.
>>
>> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>
>> Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
>> ---
>>   drivers/fpga/fpga-bridge.c | 106 ++++++++++++++++++-------------------
>>   1 file changed, 52 insertions(+), 54 deletions(-)
>>
>> diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
>> index a6c25dee9cc1..6e38ddaf16cf 100644
>> --- a/drivers/fpga/fpga-bridge.c
>> +++ b/drivers/fpga/fpga-bridge.c
>> @@ -14,7 +14,6 @@
>>   #include <linux/spinlock.h>
>>   
>>   static DEFINE_IDA(fpga_bridge_ida);
>> -static struct class *fpga_bridge_class;
> 
> Could we still use the forward declaration, to avoid moving too
> much code block.
> 
>>   
>>   /* Lock for adding/removing bridges to linked lists*/
>>   static DEFINE_SPINLOCK(bridge_list_lock);
>> @@ -84,6 +83,53 @@ static struct fpga_bridge *__fpga_bridge_get(struct device *dev,
>>   	return ERR_PTR(ret);
>>   }
>>   
>> +static ssize_t name_show(struct device *dev,
>> +			 struct device_attribute *attr, char *buf)
>> +{
>> +	struct fpga_bridge *bridge = to_fpga_bridge(dev);
>> +
>> +	return sprintf(buf, "%s\n", bridge->name);
>> +}
>> +
>> +static ssize_t state_show(struct device *dev,
>> +			  struct device_attribute *attr, char *buf)
>> +{
>> +	struct fpga_bridge *bridge = to_fpga_bridge(dev);
>> +	int state = 1;
>> +
>> +	if (bridge->br_ops && bridge->br_ops->enable_show) {
>> +		state = bridge->br_ops->enable_show(bridge);
>> +		if (state < 0)
>> +			return state;
>> +	}
>> +
>> +	return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
>> +}
>> +
>> +static DEVICE_ATTR_RO(name);
>> +static DEVICE_ATTR_RO(state);
>> +
>> +static struct attribute *fpga_bridge_attrs[] = {
>> +	&dev_attr_name.attr,
>> +	&dev_attr_state.attr,
>> +	NULL,
>> +};
>> +ATTRIBUTE_GROUPS(fpga_bridge);
>> +
>> +static void fpga_bridge_dev_release(struct device *dev)
>> +{
>> +	struct fpga_bridge *bridge = to_fpga_bridge(dev);
>> +
>> +	ida_free(&fpga_bridge_ida, bridge->dev.id);
>> +	kfree(bridge);
>> +}
>> +
>> +static const struct class fpga_bridge_class = {
>> +	.name = "fpga_bridge",
>> +	.dev_groups = fpga_bridge_groups,
>> +	.dev_release = fpga_bridge_dev_release,
>> +};
> 
> Insert them between __fpga_bridge_get() and of_fpga_bridge_get() is not
> preferred. See below comments.
> 
>> +
>>   /**
>>    * of_fpga_bridge_get - get an exclusive reference to an fpga bridge
>>    *
>> @@ -99,7 +145,7 @@ struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
>>   {
>>   	struct device *dev;
>>   
>> -	dev = class_find_device_by_of_node(fpga_bridge_class, np);
>> +	dev = class_find_device_by_of_node(&fpga_bridge_class, np);
>>   	if (!dev)
>>   		return ERR_PTR(-ENODEV);
>>   
>> @@ -126,7 +172,7 @@ struct fpga_bridge *fpga_bridge_get(struct device *dev,
>>   {
>>   	struct device *bridge_dev;
>>   
>> -	bridge_dev = class_find_device(fpga_bridge_class, NULL, dev,
>> +	bridge_dev = class_find_device(&fpga_bridge_class, NULL, dev,
>>   				       fpga_bridge_dev_match);
>>   	if (!bridge_dev)
>>   		return ERR_PTR(-ENODEV);
>> @@ -281,39 +327,6 @@ int fpga_bridge_get_to_list(struct device *dev,
>>   }
>>   EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
>>   
>> -static ssize_t name_show(struct device *dev,
>> -			 struct device_attribute *attr, char *buf)
>> -{
>> -	struct fpga_bridge *bridge = to_fpga_bridge(dev);
>> -
>> -	return sprintf(buf, "%s\n", bridge->name);
>> -}
>> -
>> -static ssize_t state_show(struct device *dev,
>> -			  struct device_attribute *attr, char *buf)
>> -{
>> -	struct fpga_bridge *bridge = to_fpga_bridge(dev);
>> -	int state = 1;
>> -
>> -	if (bridge->br_ops && bridge->br_ops->enable_show) {
>> -		state = bridge->br_ops->enable_show(bridge);
>> -		if (state < 0)
>> -			return state;
>> -	}
>> -
>> -	return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
>> -}
>> -
>> -static DEVICE_ATTR_RO(name);
>> -static DEVICE_ATTR_RO(state);
>> -
>> -static struct attribute *fpga_bridge_attrs[] = {
>> -	&dev_attr_name.attr,
>> -	&dev_attr_state.attr,
>> -	NULL,
>> -};
>> -ATTRIBUTE_GROUPS(fpga_bridge);
>> -
>>   /**
>>    * fpga_bridge_register - create and register an FPGA Bridge device
>>    * @parent:	FPGA bridge device from pdev
>> @@ -359,7 +372,7 @@ fpga_bridge_register(struct device *parent, const char *name,
>>   	bridge->priv = priv;
>>   
>>   	bridge->dev.groups = br_ops->groups;
>> -	bridge->dev.class = fpga_bridge_class;
>> +	bridge->dev.class = &fpga_bridge_class;
>>   	bridge->dev.parent = parent;
>>   	bridge->dev.of_node = parent->of_node;
>>   	bridge->dev.id = id;
>> @@ -407,29 +420,14 @@ void fpga_bridge_unregister(struct fpga_bridge *bridge)
>>   }
>>   EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
>>   
>> -static void fpga_bridge_dev_release(struct device *dev)
>> -{
>> -	struct fpga_bridge *bridge = to_fpga_bridge(dev);
>> -
>> -	ida_free(&fpga_bridge_ida, bridge->dev.id);
>> -	kfree(bridge);
>> -}
>> -
> 
> How about put the fpga_bridge_class definition here?
> 
> Thanks,
> Yilun

Hi Yilun,

Thank you for the review, I agree that forward declaration is better in 
this case. I'll send you the V2 after making suggested changes.

--
Kind regards,
Ivan Orlov