From 9f0fc191371843c4fc000a226b0a26b6c059aacd Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sat, 18 May 2024 19:40:19 +0200
Subject: Merging upstream version 6.7.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 include/linux/tracefs.h | 73 +++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 58 insertions(+), 15 deletions(-)

(limited to 'include/linux/tracefs.h')

diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h
index 009072792..7a5fe17b6 100644
--- a/include/linux/tracefs.h
+++ b/include/linux/tracefs.h
@@ -23,26 +23,69 @@ struct file_operations;
 
 struct eventfs_file;
 
-struct dentry *eventfs_create_events_dir(const char *name,
-					 struct dentry *parent);
-
-struct eventfs_file *eventfs_add_subsystem_dir(const char *name,
-					       struct dentry *parent);
+/**
+ * eventfs_callback - A callback function to create dynamic files in eventfs
+ * @name: The name of the file that is to be created
+ * @mode: return the file mode for the file (RW access, etc)
+ * @data: data to pass to the created file ops
+ * @fops: the file operations of the created file
+ *
+ * The evetnfs files are dynamically created. The struct eventfs_entry array
+ * is passed to eventfs_create_dir() or eventfs_create_events_dir() that will
+ * be used to create the files within those directories. When a lookup
+ * or access to a file within the directory is made, the struct eventfs_entry
+ * array is used to find a callback() with the matching name that is being
+ * referenced (for lookups, the entire array is iterated and each callback
+ * will be called).
+ *
+ * The callback will be called with @name for the name of the file to create.
+ * The callback can return less than 1 to indicate  that no file should be
+ * created.
+ *
+ * If a file is to be created, then @mode should be populated with the file
+ * mode (permissions) for which the file is created for. This would be
+ * used to set the created inode i_mode field.
+ *
+ * The @data should be set to the data passed to the other file operations
+ * (read, write, etc). Note, @data will also point to the data passed in
+ * to eventfs_create_dir() or eventfs_create_events_dir(), but the callback
+ * can replace the data if it chooses to. Otherwise, the original data
+ * will be used for the file operation functions.
+ *
+ * The @fops should be set to the file operations that will be used to create
+ * the inode.
+ *
+ * NB. This callback is called while holding internal locks of the eventfs
+ *     system. The callback must not call any code that might also call into
+ *     the tracefs or eventfs system or it will risk creating a deadlock.
+ */
+typedef int (*eventfs_callback)(const char *name, umode_t *mode, void **data,
+				const struct file_operations **fops);
 
-struct eventfs_file *eventfs_add_dir(const char *name,
-				     struct eventfs_file *ef_parent);
+/**
+ * struct eventfs_entry - dynamically created eventfs file call back handler
+ * @name:	Then name of the dynamic file in an eventfs directory
+ * @callback:	The callback to get the fops of the file when it is created
+ *
+ * See evenfs_callback() typedef for how to set up @callback.
+ */
+struct eventfs_entry {
+	const char			*name;
+	eventfs_callback		callback;
+};
 
-int eventfs_add_file(const char *name, umode_t mode,
-		     struct eventfs_file *ef_parent, void *data,
-		     const struct file_operations *fops);
+struct eventfs_inode;
 
-int eventfs_add_events_file(const char *name, umode_t mode,
-			 struct dentry *parent, void *data,
-			 const struct file_operations *fops);
+struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry *parent,
+						const struct eventfs_entry *entries,
+						int size, void *data);
 
-void eventfs_remove(struct eventfs_file *ef);
+struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode *parent,
+					 const struct eventfs_entry *entries,
+					 int size, void *data);
 
-void eventfs_remove_events_dir(struct dentry *dentry);
+void eventfs_remove_events_dir(struct eventfs_inode *ei);
+void eventfs_remove_dir(struct eventfs_inode *ei);
 
 struct dentry *tracefs_create_file(const char *name, umode_t mode,
 				   struct dentry *parent, void *data,
-- 
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