This is a note to let you know that I've just added the patch titled
eventfs: Shortcut eventfs_iterate() by skipping entries already read
to the 6.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
eventfs-shortcut-eventfs_iterate-by-skipping-entries-already-read.patch
and it can be found in the queue-6.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From SRS0=eEWY=JP=rostedt.homelinux.com=rostedt@xxxxxxxxxx Tue Feb 6 12:33:32 2024
From: Steven Rostedt <rostedt@xxxxxxxxxxx>
Date: Tue, 06 Feb 2024 06:32:05 -0500
Subject: eventfs: Shortcut eventfs_iterate() by skipping entries already read
To: linux-kernel@xxxxxxxxxxxxxxx, stable@xxxxxxxxxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Sasha Levin <sashal@xxxxxxxxxx>, Masami Hiramatsu <mhiramat@xxxxxxxxxx>, Mark Rutland <mark.rutland@xxxxxxx>, Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Al Viro <viro@xxxxxxxxxxxxxxxxxx>, Christian Brauner <brauner@xxxxxxxxxx>
Message-ID: <20240206113359.229236339@xxxxxxxxxxxxxxxxxxxxx>
From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
commit 1de94b52d5e8d8b32f0252f14fad1f1edc2e71f1 upstream.
As the ei->entries array is fixed for the duration of the eventfs_inode,
it can be used to skip over already read entries in eventfs_iterate().
That is, if ctx->pos is greater than zero, there's no reason in doing the
loop across the ei->entries array for the entries less than ctx->pos.
Instead, start the lookup of the entries at the current ctx->pos.
Link: https://lore.kernel.org/all/CAHk-=wiKwDUDv3+jCsv-uacDcHDVTYsXtBR9=6sGM5mqX+DhOg@xxxxxxxxxxxxxx/
Link: https://lore.kernel.org/linux-trace-kernel/20240104220048.494956957@xxxxxxxxxxx
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/tracefs/event_inode.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -708,21 +708,15 @@ static int eventfs_iterate(struct file *
if (!ei || !ei_dentry)
goto out;
- ret = 0;
-
/*
* Need to create the dentries and inodes to have a consistent
* inode number.
*/
- for (i = 0; i < ei->nr_entries; i++) {
- void *cdata = ei->data;
-
- if (c > 0) {
- c--;
- continue;
- }
+ ret = 0;
- ctx->pos++;
+ /* Start at 'c' to jump over already read entries */
+ for (i = c; i < ei->nr_entries; i++, ctx->pos++) {
+ void *cdata = ei->data;
entry = &ei->entries[i];
name = entry->name;
@@ -731,7 +725,7 @@ static int eventfs_iterate(struct file *
/* If ei->is_freed then just bail here, nothing more to do */
if (ei->is_freed) {
mutex_unlock(&eventfs_mutex);
- goto out_dec;
+ goto out;
}
r = entry->callback(name, &mode, &cdata, &fops);
mutex_unlock(&eventfs_mutex);
@@ -740,14 +734,17 @@ static int eventfs_iterate(struct file *
dentry = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
if (!dentry)
- goto out_dec;
+ goto out;
ino = dentry->d_inode->i_ino;
dput(dentry);
if (!dir_emit(ctx, name, strlen(name), ino, DT_REG))
- goto out_dec;
+ goto out;
}
+ /* Subtract the skipped entries above */
+ c -= min((unsigned int)c, (unsigned int)ei->nr_entries);
+
list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
Patches currently in stable-queue which might be from rostedt@xxxxxxxxxx are
queue-6.7/eventfs-keep-all-directory-links-at-1.patch
queue-6.7/eventfs-save-directory-inodes-in-the-eventfs_inode-structure.patch
queue-6.7/tracefs-zero-out-the-tracefs_inode-when-allocating-it.patch
queue-6.7/eventfs-read-ei-entries-before-ei-children-in-eventfs_iterate.patch
queue-6.7/eventfs-remove-lookup-parameter-from-create_dir-file_dentry.patch
queue-6.7/eventfs-remove-fsnotify-functions-from-lookup.patch
queue-6.7/eventfs-stop-using-dcache_readdir-for-getdents.patch
queue-6.7/tracefs-avoid-using-the-ei-dentry-pointer-unnecessarily.patch
queue-6.7/eventfs-initialize-the-tracefs-inode-properly.patch
queue-6.7/eventfs-do-ctx-pos-update-for-all-iterations-in-eventfs_iterate.patch
queue-6.7/tracefs-dentry-lookup-crapectomy.patch
queue-6.7/eventfs-have-the-inodes-all-for-files-and-directories-all-be-the-same.patch
queue-6.7/eventfs-use-kcalloc-instead-of-kzalloc.patch
queue-6.7/eventfs-shortcut-eventfs_iterate-by-skipping-entries-already-read.patch
queue-6.7/eventfs-do-not-create-dentries-nor-inodes-in-iterate_shared.patch
queue-6.7/eventfs-have-eventfs_iterate-stop-immediately-if-ei-is_freed-is-set.patch
queue-6.7/eventfs-restructure-eventfs_inode-structure-to-be-more-condensed.patch
queue-6.7/eventfs-warn-if-an-eventfs_inode-is-freed-without-is_freed-being-set.patch
queue-6.7/eventfs-get-rid-of-dentry-pointers-without-refcounts.patch
queue-6.7/eventfs-remove-unused-d_parent-pointer-field.patch
queue-6.7/eventfs-clean-up-dentry-ops-and-add-revalidate-function.patch
