[PATCH 6/6] of: make kobject and bin_attribute support configurable

From: Rob Herring
Date: Thu Oct 05 2017 - 15:45:05 EST

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Next in thread: Rob Herring: "[PATCH 4/6] of: move kobj_to_device_node() into dynamic.c"
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Having device_nodes be kobjects is only needed if sysfs or OF_DYNAMIC is
enabled. Otherwise, having a kobject in struct device_node is
unnecessary bloat in minimal kernel configurations.

Likewise, bin_attribute is only needed in struct property when sysfs is
enabled, so we can make it configurable too.

Cc: Nicolas Pitre <nico@xxxxxxxxxx>
Cc: Frank Rowand <frowand.list@xxxxxxxxx>
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
---
drivers/of/Kconfig | 4 ++
drivers/of/Makefile | 1 +
drivers/of/base.c | 130 --------------------------------------
drivers/of/dynamic.c | 22 -------
drivers/of/kobj.c | 164 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/of/of_private.h | 23 +++++++
include/linux/of.h | 22 +++----
7 files changed, 202 insertions(+), 164 deletions(-)
create mode 100644 drivers/of/kobj.c

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index ba7b034b2b91..ad9a9578f9c4 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -46,10 +46,14 @@ config OF_EARLY_FLATTREE
config OF_PROMTREE
bool

+config OF_KOBJ
+ def_bool SYSFS
+
# Hardly any platforms need this. It is safe to select, but only do so if you
# need it.
config OF_DYNAMIC
bool "Support for dynamic device trees" if OF_UNITTEST
+ select OF_KOBJ
help
On some platforms, the device tree can be manipulated at runtime.
While this option is selected automatically on such platforms, you
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 97dc01c81438..83d61a7c5e82 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -1,4 +1,5 @@
obj-y = base.o device.o platform.o property.o
+obj-$(CONFIG_OF_KOBJ) += kobj.o
obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
obj-$(CONFIG_OF_FLATTREE) += fdt.o
obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 9e9bd17121fb..b98f3adffbb0 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -95,105 +95,6 @@ int __weak of_node_to_nid(struct device_node *np)
}
#endif

-#ifndef CONFIG_OF_DYNAMIC
-static void of_node_release(struct kobject *kobj)
-{
- /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
-}
-#endif /* CONFIG_OF_DYNAMIC */
-
-struct kobj_type of_node_ktype = {
- .release = of_node_release,
-};
-
-static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
- struct bin_attribute *bin_attr, char *buf,
- loff_t offset, size_t count)
-{
- struct property *pp = container_of(bin_attr, struct property, attr);
- return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
-}
-
-/* always return newly allocated name, caller must free after use */
-static const char *safe_name(struct kobject *kobj, const char *orig_name)
-{
- const char *name = orig_name;
- struct kernfs_node *kn;
- int i = 0;
-
- /* don't be a hero. After 16 tries give up */
- while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
- sysfs_put(kn);
- if (name != orig_name)
- kfree(name);
- name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
- }
-
- if (name == orig_name) {
- name = kstrdup(orig_name, GFP_KERNEL);
- } else {
- pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
- kobject_name(kobj), name);
- }
- return name;
-}
-
-int __of_add_property_sysfs(struct device_node *np, struct property *pp)
-{
- int rc;
-
- /* Important: Don't leak passwords */
- bool secure = strncmp(pp->name, "security-", 9) == 0;
-
- if (!IS_ENABLED(CONFIG_SYSFS))
- return 0;
-
- if (!of_kset || !of_node_is_attached(np))
- return 0;
-
- sysfs_bin_attr_init(&pp->attr);
- pp->attr.attr.name = safe_name(&np->kobj, pp->name);
- pp->attr.attr.mode = secure ? 0400 : 0444;
- pp->attr.size = secure ? 0 : pp->length;
- pp->attr.read = of_node_property_read;
-
- rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
- WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
- return rc;
-}
-
-int __of_attach_node_sysfs(struct device_node *np)
-{
- const char *name;
- struct kobject *parent;
- struct property *pp;
- int rc;
-
- if (!of_kset)
- return 0;
-
- np->kobj.kset = of_kset;
- if (!np->parent) {
- /* Nodes without parents are new top level trees */
- name = safe_name(&of_kset->kobj, "base");
- parent = NULL;
- } else {
- name = safe_name(&np->parent->kobj, kbasename(np->full_name));
- parent = &np->parent->kobj;
- }
- if (!name)
- return -ENOMEM;
- rc = kobject_add(&np->kobj, parent, "%s", name);
- kfree(name);
- if (rc)
- return rc;
-
- for_each_property_of_node(np, pp)
- __of_add_property_sysfs(np, pp);
-
- return 0;
-}
-
void __init of_core_init(void)
{
struct device_node *np;
@@ -1501,22 +1402,6 @@ int __of_remove_property(struct device_node *np, struct property *prop)
return 0;
}

-void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
-{
- sysfs_remove_bin_file(&np->kobj, &prop->attr);
- kfree(prop->attr.attr.name);
-}
-
-void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
-{
- if (!IS_ENABLED(CONFIG_SYSFS))
- return;
-
- /* at early boot, bail here and defer setup to of_init() */
- if (of_kset && of_node_is_attached(np))
- __of_sysfs_remove_bin_file(np, prop);
-}
-
/**
* of_remove_property - Remove a property from a node.
*
@@ -1576,21 +1461,6 @@ int __of_update_property(struct device_node *np, struct property *newprop,
return 0;
}

-void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
- struct property *oldprop)
-{
- if (!IS_ENABLED(CONFIG_SYSFS))
- return;
-
- /* At early boot, bail out and defer setup to of_init() */
- if (!of_kset)
- return;
-
- if (oldprop)
- __of_sysfs_remove_bin_file(np, oldprop);
- __of_add_property_sysfs(np, newprop);
-}
-
/*
* of_update_property - Update a property in a node, if the property does
* not exist, add it.
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 9d6ba18c529f..39e8cf731764 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -48,28 +48,6 @@ void of_node_put(struct device_node *node)
}
EXPORT_SYMBOL(of_node_put);

-void __of_detach_node_sysfs(struct device_node *np)
-{
- struct property *pp;
-
- if (!IS_ENABLED(CONFIG_SYSFS))
- return;
-
- BUG_ON(!of_node_is_initialized(np));
- if (!of_kset)
- return;
-
- /* only remove properties if on sysfs */
- if (of_node_is_attached(np)) {
- for_each_property_of_node(np, pp)
- __of_sysfs_remove_bin_file(np, pp);
- kobject_del(&np->kobj);
- }
-
- /* finally remove the kobj_init ref */
- of_node_put(np);
-}
-
static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);

int of_reconfig_notifier_register(struct notifier_block *nb)
diff --git a/drivers/of/kobj.c b/drivers/of/kobj.c
new file mode 100644
index 000000000000..250fc7bb550f
--- /dev/null
+++ b/drivers/of/kobj.c
@@ -0,0 +1,164 @@
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#include "of_private.h"
+
+/* true when node is initialized */
+static int of_node_is_initialized(struct device_node *node)
+{
+ return node && node->kobj.state_initialized;
+}
+
+/* true when node is attached (i.e. present on sysfs) */
+int of_node_is_attached(struct device_node *node)
+{
+ return node && node->kobj.state_in_sysfs;
+}
+
+
+#ifndef CONFIG_OF_DYNAMIC
+static void of_node_release(struct kobject *kobj)
+{
+ /* Without CONFIG_OF_DYNAMIC, no nodes gets freed */
+}
+#endif /* CONFIG_OF_DYNAMIC */
+
+struct kobj_type of_node_ktype = {
+ .release = of_node_release,
+};
+
+static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr, char *buf,
+ loff_t offset, size_t count)
+{
+ struct property *pp = container_of(bin_attr, struct property, attr);
+ return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);
+}
+
+/* always return newly allocated name, caller must free after use */
+static const char *safe_name(struct kobject *kobj, const char *orig_name)
+{
+ const char *name = orig_name;
+ struct kernfs_node *kn;
+ int i = 0;
+
+ /* don't be a hero. After 16 tries give up */
+ while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {
+ sysfs_put(kn);
+ if (name != orig_name)
+ kfree(name);
+ name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);
+ }
+
+ if (name == orig_name) {
+ name = kstrdup(orig_name, GFP_KERNEL);
+ } else {
+ pr_warn("Duplicate name in %s, renamed to \"%s\"\n",
+ kobject_name(kobj), name);
+ }
+ return name;
+}
+
+int __of_add_property_sysfs(struct device_node *np, struct property *pp)
+{
+ int rc;
+
+ /* Important: Don't leak passwords */
+ bool secure = strncmp(pp->name, "security-", 9) == 0;
+
+ if (!IS_ENABLED(CONFIG_SYSFS))
+ return 0;
+
+ if (!of_kset || !of_node_is_attached(np))
+ return 0;
+
+ sysfs_bin_attr_init(&pp->attr);
+ pp->attr.attr.name = safe_name(&np->kobj, pp->name);
+ pp->attr.attr.mode = secure ? 0400 : 0444;
+ pp->attr.size = secure ? 0 : pp->length;
+ pp->attr.read = of_node_property_read;
+
+ rc = sysfs_create_bin_file(&np->kobj, &pp->attr);
+ WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);
+ return rc;
+}
+
+void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)
+{
+ if (!IS_ENABLED(CONFIG_SYSFS))
+ return;
+
+ sysfs_remove_bin_file(&np->kobj, &prop->attr);
+ kfree(prop->attr.attr.name);
+}
+
+void __of_remove_property_sysfs(struct device_node *np, struct property *prop)
+{
+ /* at early boot, bail here and defer setup to of_init() */
+ if (of_kset && of_node_is_attached(np))
+ __of_sysfs_remove_bin_file(np, prop);
+}
+
+void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
+ struct property *oldprop)
+{
+ /* At early boot, bail out and defer setup to of_init() */
+ if (!of_kset)
+ return;
+
+ if (oldprop)
+ __of_sysfs_remove_bin_file(np, oldprop);
+ __of_add_property_sysfs(np, newprop);
+}
+
+int __of_attach_node_sysfs(struct device_node *np)
+{
+ const char *name;
+ struct kobject *parent;
+ struct property *pp;
+ int rc;
+
+ if (!of_kset)
+ return 0;
+
+ np->kobj.kset = of_kset;
+ if (!np->parent) {
+ /* Nodes without parents are new top level trees */
+ name = safe_name(&of_kset->kobj, "base");
+ parent = NULL;
+ } else {
+ name = safe_name(&np->parent->kobj, kbasename(np->full_name));
+ parent = &np->parent->kobj;
+ }
+ if (!name)
+ return -ENOMEM;
+ rc = kobject_add(&np->kobj, parent, "%s", name);
+ kfree(name);
+ if (rc)
+ return rc;
+
+ for_each_property_of_node(np, pp)
+ __of_add_property_sysfs(np, pp);
+
+ return 0;
+}
+
+void __of_detach_node_sysfs(struct device_node *np)
+{
+ struct property *pp;
+
+ BUG_ON(!of_node_is_initialized(np));
+ if (!of_kset)
+ return;
+
+ /* only remove properties if on sysfs */
+ if (of_node_is_attached(np)) {
+ for_each_property_of_node(np, pp)
+ __of_sysfs_remove_bin_file(np, pp);
+ kobject_del(&np->kobj);
+ }
+
+ /* finally remove the kobj_init ref */
+ of_node_put(np);
+}
+
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index cc86a974f35f..43df14f0cbce 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -49,6 +49,29 @@ static inline int of_property_notify(int action, struct device_node *np,
}
#endif /* CONFIG_OF_DYNAMIC */

+#if defined(CONFIG_OF_KOBJ)
+int of_node_is_attached(struct device_node *node);
+int __of_add_property_sysfs(struct device_node *np, struct property *pp);
+void __of_remove_property_sysfs(struct device_node *np, struct property *prop);
+void __of_update_property_sysfs(struct device_node *np, struct property *newprop,
+ struct property *oldprop);
+int __of_attach_node_sysfs(struct device_node *np);
+void __of_detach_node_sysfs(struct device_node *np);
+#else
+static inline int __of_add_property_sysfs(struct device_node *np, struct property *pp)
+{
+ return 0;
+}
+static inline void __of_remove_property_sysfs(struct device_node *np, struct property *prop) {}
+static inline void __of_update_property_sysfs(struct device_node *np,
+ struct property *newprop, struct property *oldprop) {}
+static inline int __of_attach_node_sysfs(struct device_node *np)
+{
+ return 0;
+}
+static inline void __of_detach_node_sysfs(struct device_node *np) {}
+#endif
+
#if defined(CONFIG_OF_UNITTEST) && defined(CONFIG_OF_OVERLAY)
extern void __init unittest_unflatten_overlay_base(void);
#else
diff --git a/include/linux/of.h b/include/linux/of.h
index 2d685e769409..7b0f17be7830 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -43,7 +43,9 @@ struct property {
#if defined(CONFIG_OF_PROMTREE)
unsigned int unique_id;
#endif
+#if defined(CONFIG_OF_KOBJ)
struct bin_attribute attr;
+#endif
};

#if defined(CONFIG_SPARC)
@@ -62,7 +64,9 @@ struct device_node {
struct device_node *parent;
struct device_node *child;
struct device_node *sibling;
+#if defined(CONFIG_OF_KOBJ)
struct kobject kobj;
+#endif
unsigned long _flags;
void *data;
#if defined(CONFIG_SPARC)
@@ -107,23 +111,17 @@ extern struct kobj_type of_node_ktype;
extern const struct fwnode_operations of_fwnode_ops;
static inline void of_node_init(struct device_node *node)
{
+#if defined(CONFIG_OF_KOBJ)
kobject_init(&node->kobj, &of_node_ktype);
+#endif
node->fwnode.ops = &of_fwnode_ops;
}

+#if defined(CONFIG_OF_KOBJ)
#define of_node_kobj(n) (&(n)->kobj)
-
-/* true when node is initialized */
-static inline int of_node_is_initialized(struct device_node *node)
-{
- return node && node->kobj.state_initialized;
-}
-
-/* true when node is attached (i.e. present on sysfs) */
-static inline int of_node_is_attached(struct device_node *node)
-{
- return node && node->kobj.state_in_sysfs;
-}
+#else
+#define of_node_kobj(n) NULL
+#endif

#ifdef CONFIG_OF_DYNAMIC
extern struct device_node *of_node_get(struct device_node *node);
--
2.11.0

Next message: Rob Herring: "[PATCH 4/6] of: move kobj_to_device_node() into dynamic.c"
Previous message: Tim Hansen: "[PATCH] net/ipv6: remove unused err variable on icmpv6_push_pending_frames"
In reply to: Greg Kroah-Hartman: "Re: [PATCH 5/6] of: wrap accesses to device_node kobject"
Next in thread: Rob Herring: "[PATCH 4/6] of: move kobj_to_device_node() into dynamic.c"
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