[PATCH] eventfs: Restructure eventfs_inode structure to be more condensed

From: Steven Rostedt
Date: Wed Jan 31 2024 - 14:51:10 EST


From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>

Some of the eventfs_inode structure has holes in it. Rework the structure
to be a bit more condensed, and also remove the no longer used llist
field.

Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wgh0otaSyV0MNrQpwFDTjT3=TWV94Wit2eUuPdh2KdyVg@xxxxxxxxxxxxxx/

Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
fs/tracefs/internal.h | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 1886f1826cd8..beb3dcd0e434 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -32,40 +32,37 @@ struct eventfs_attr {
/*
* struct eventfs_inode - hold the properties of the eventfs directories.
* @list: link list into the parent directory
+ * @rcu: Union with @list for freeing
+ * @children: link list into the child eventfs_inode
* @entries: the array of entries representing the files in the directory
* @name: the name of the directory to create
- * @children: link list into the child eventfs_inode
* @events_dir: the dentry of the events directory
* @entry_attrs: Saved mode and ownership of the @d_children
- * @attr: Saved mode and ownership of eventfs_inode itself
* @data: The private data to pass to the callbacks
+ * @attr: Saved mode and ownership of eventfs_inode itself
* @is_freed: Flag set if the eventfs is on its way to be freed
* Note if is_freed is set, then dentry is corrupted.
+ * @is_events: Flag set for only the top level "events" directory
* @nr_entries: The number of items in @entries
+ * @ino: The saved inode number
*/
struct eventfs_inode {
- struct kref kref;
- struct list_head list;
+ union {
+ struct list_head list;
+ struct rcu_head rcu;
+ };
+ struct list_head children;
const struct eventfs_entry *entries;
const char *name;
- struct list_head children;
struct dentry *events_dir;
struct eventfs_attr *entry_attrs;
- struct eventfs_attr attr;
void *data;
+ struct eventfs_attr attr;
+ struct kref kref;
unsigned int is_freed:1;
unsigned int is_events:1;
unsigned int nr_entries:30;
unsigned int ino;
- /*
- * Union - used for deletion
- * @llist: for calling dput() if needed after RCU
- * @rcu: eventfs_inode to delete in RCU
- */
- union {
- struct llist_node llist;
- struct rcu_head rcu;
- };
};

static inline struct tracefs_inode *get_tracefs(const struct inode *inode)
--
2.43.0