Merge tag 'driver-core-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the "big" set of driver core and kernfs changes for 6.9-rc1.

  Nothing all that crazy here, just some good updates that include:

   - automatic attribute group hiding from Dan Williams (he fixed up my
     horrible attempt at doing this.)

   - kobject lock contention fixes from Eric Dumazet

   - driver core cleanups from Andy

   - kernfs rcu work from Tejun

   - fw_devlink changes to resolve some reported issues

   - other minor changes, all details in the shortlog

  All of these have been in linux-next for a long time with no reported
  issues"

* tag 'driver-core-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (28 commits)
  device: core: Log warning for devices pending deferred probe on timeout
  driver: core: Use dev_* instead of pr_* so device metadata is added
  driver: core: Log probe failure as error and with device metadata
  of: property: fw_devlink: Add support for "post-init-providers" property
  driver core: Add FWLINK_FLAG_IGNORE to completely ignore a fwnode link
  driver core: Adds flags param to fwnode_link_add()
  debugfs: fix wait/cancellation handling during remove
  device property: Don't use "proxy" headers
  device property: Move enum dev_dma_attr to fwnode.h
  driver core: Move fw_devlink stuff to where it belongs
  driver core: Drop unneeded 'extern' keyword in fwnode.h
  firmware_loader: Suppress warning on FW_OPT_NO_WARN flag
  sysfs:Addresses documentation in sysfs_merge_group and sysfs_unmerge_group.
  firmware_loader: introduce __free() cleanup hanler
  platform-msi: Remove usage of the deprecated ida_simple_xx() API
  sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE()
  sysfs: Document new "group visible" helpers
  sysfs: Fix crash on empty group attributes array
  sysfs: Introduce a mechanism to hide static attribute_groups
  sysfs: Introduce a mechanism to hide static attribute_groups
  ...

1 files changed, 130 insertions, 12 deletions

diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index b717a70219f651..326341c623857e 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -61,22 +61,32 @@ do {							\
 /**
  * struct attribute_group - data structure used to declare an attribute group.
  * @name:	Optional: Attribute group name
- *		If specified, the attribute group will be created in
- *		a new subdirectory with this name.
+ *		If specified, the attribute group will be created in a
+ *		new subdirectory with this name. Additionally when a
+ *		group is named, @is_visible and @is_bin_visible may
+ *		return SYSFS_GROUP_INVISIBLE to control visibility of
+ *		the directory itself.
  * @is_visible:	Optional: Function to return permissions associated with an
- *		attribute of the group. Will be called repeatedly for each
- *		non-binary attribute in the group. Only read/write
+ *		attribute of the group. Will be called repeatedly for
+ *		each non-binary attribute in the group. Only read/write
  *		permissions as well as SYSFS_PREALLOC are accepted. Must
- *		return 0 if an attribute is not visible. The returned value
- *		will replace static permissions defined in struct attribute.
+ *		return 0 if an attribute is not visible. The returned
+ *		value will replace static permissions defined in struct
+ *		attribute. Use SYSFS_GROUP_VISIBLE() when assigning this
+ *		callback to specify separate _group_visible() and
+ *		_attr_visible() handlers.
  * @is_bin_visible:
  *		Optional: Function to return permissions associated with a
  *		binary attribute of the group. Will be called repeatedly
  *		for each binary attribute in the group. Only read/write
- *		permissions as well as SYSFS_PREALLOC are accepted. Must
- *		return 0 if a binary attribute is not visible. The returned
- *		value will replace static permissions defined in
- *		struct bin_attribute.
+ *		permissions as well as SYSFS_PREALLOC (and the
+ *		visibility flags for named groups) are accepted. Must
+ *		return 0 if a binary attribute is not visible. The
+ *		returned value will replace static permissions defined
+ *		in struct bin_attribute. If @is_visible is not set, Use
+ *		SYSFS_GROUP_VISIBLE() when assigning this callback to
+ *		specify separate _group_visible() and _attr_visible()
+ *		handlers.
  * @attrs:	Pointer to NULL terminated list of attributes.
  * @bin_attrs:	Pointer to NULL terminated list of binary attributes.
  *		Either attrs or bin_attrs or both must be provided.
@@ -91,13 +101,121 @@ struct attribute_group {
 	struct bin_attribute	**bin_attrs;
 };
 
+#define SYSFS_PREALLOC		010000
+#define SYSFS_GROUP_INVISIBLE	020000
+
+/*
+ * DEFINE_SYSFS_GROUP_VISIBLE(name):
+ *	A helper macro to pair with the assignment of ".is_visible =
+ *	SYSFS_GROUP_VISIBLE(name)", that arranges for the directory
+ *	associated with a named attribute_group to optionally be hidden.
+ *	This allows for static declaration of attribute_groups, and the
+ *	simplification of attribute visibility lifetime that implies,
+ *	without polluting sysfs with empty attribute directories.
+ * Ex.
+ *
+ * static umode_t example_attr_visible(struct kobject *kobj,
+ *                                   struct attribute *attr, int n)
+ * {
+ *       if (example_attr_condition)
+ *               return 0;
+ *       else if (ro_attr_condition)
+ *               return 0444;
+ *       return a->mode;
+ * }
+ *
+ * static bool example_group_visible(struct kobject *kobj)
+ * {
+ *       if (example_group_condition)
+ *               return false;
+ *       return true;
+ * }
+ *
+ * DEFINE_SYSFS_GROUP_VISIBLE(example);
+ *
+ * static struct attribute_group example_group = {
+ *       .name = "example",
+ *       .is_visible = SYSFS_GROUP_VISIBLE(example),
+ *       .attrs = &example_attrs,
+ * };
+ *
+ * Note that it expects <name>_attr_visible and <name>_group_visible to
+ * be defined. For cases where individual attributes do not need
+ * separate visibility consideration, only entire group visibility at
+ * once, see DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE().
+ */
+#define DEFINE_SYSFS_GROUP_VISIBLE(name)                             \
+	static inline umode_t sysfs_group_visible_##name(            \
+		struct kobject *kobj, struct attribute *attr, int n) \
+	{                                                            \
+		if (n == 0 && !name##_group_visible(kobj))           \
+			return SYSFS_GROUP_INVISIBLE;                \
+		return name##_attr_visible(kobj, attr, n);           \
+	}
+
+/*
+ * DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE(name):
+ *	A helper macro to pair with SYSFS_GROUP_VISIBLE() that like
+ *	DEFINE_SYSFS_GROUP_VISIBLE() controls group visibility, but does
+ *	not require the implementation of a per-attribute visibility
+ *	callback.
+ * Ex.
+ *
+ * static bool example_group_visible(struct kobject *kobj)
+ * {
+ *       if (example_group_condition)
+ *               return false;
+ *       return true;
+ * }
+ *
+ * DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE(example);
+ *
+ * static struct attribute_group example_group = {
+ *       .name = "example",
+ *       .is_visible = SYSFS_GROUP_VISIBLE(example),
+ *       .attrs = &example_attrs,
+ * };
+ */
+#define DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE(name)                   \
+	static inline umode_t sysfs_group_visible_##name(         \
+		struct kobject *kobj, struct attribute *a, int n) \
+	{                                                         \
+		if (n == 0 && !name##_group_visible(kobj))        \
+			return SYSFS_GROUP_INVISIBLE;             \
+		return a->mode;                                   \
+	}
+
+/*
+ * Same as DEFINE_SYSFS_GROUP_VISIBLE, but for groups with only binary
+ * attributes. If an attribute_group defines both text and binary
+ * attributes, the group visibility is determined by the function
+ * specified to is_visible() not is_bin_visible()
+ */
+#define DEFINE_SYSFS_BIN_GROUP_VISIBLE(name)                             \
+	static inline umode_t sysfs_group_visible_##name(                \
+		struct kobject *kobj, struct bin_attribute *attr, int n) \
+	{                                                                \
+		if (n == 0 && !name##_group_visible(kobj))               \
+			return SYSFS_GROUP_INVISIBLE;                    \
+		return name##_attr_visible(kobj, attr, n);               \
+	}
+
+#define DEFINE_SIMPLE_SYSFS_BIN_GROUP_VISIBLE(name)                   \
+	static inline umode_t sysfs_group_visible_##name(             \
+		struct kobject *kobj, struct bin_attribute *a, int n) \
+	{                                                             \
+		if (n == 0 && !name##_group_visible(kobj))            \
+			return SYSFS_GROUP_INVISIBLE;                 \
+		return a->mode;                                       \
+	}
+
+#define SYSFS_GROUP_VISIBLE(fn) sysfs_group_visible_##fn
+
 /*
  * Use these macros to make defining attributes easier.
  * See include/linux/device.h for examples..
  */
 
-#define SYSFS_PREALLOC 010000
-
 #define __ATTR(_name, _mode, _show, _store) {				\
 	.attr = {.name = __stringify(_name),				\
 		 .mode = VERIFY_OCTAL_PERMISSIONS(_mode) },		\