Re: [PATCH] blktrace: remove debugfs file dentries from struct blk_trace

From: Steven Rostedt
Date: Mon Feb 22 2021 - 18:03:43 EST



Jens,

I guess this goes through your tree.

I'm pinging you in case you did what I did, and confused this patch as one
of Greg's stable patches (which I almost archived as such)!

No, this is an actual update from Greg, not a patch that was backported.

-- Steve

On Tue, 16 Feb 2021 16:52:47 +0100
Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:

> These debugfs dentries do not need to be saved for anything as the whole
> directory and everything in it is properly cleaned up when the parent
> directory is removed. So remove them from struct blk_trace and don't
> save them when created as it's not necessary.
>
> Cc: Jens Axboe <axboe@xxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: linux-block@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
> include/linux/blktrace_api.h | 2 --
> kernel/trace/blktrace.c | 8 ++------
> 2 files changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
> index 05556573b896..79979d33c140 100644
> --- a/include/linux/blktrace_api.h
> +++ b/include/linux/blktrace_api.h
> @@ -23,8 +23,6 @@ struct blk_trace {
> u32 pid;
> u32 dev;
> struct dentry *dir;
> - struct dentry *dropped_file;
> - struct dentry *msg_file;
> struct list_head running_list;
> atomic_t dropped;
> };
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index fb0fe4c66b84..67c730f0b6ef 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -311,8 +311,6 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
>
> static void blk_trace_free(struct blk_trace *bt)
> {
> - debugfs_remove(bt->msg_file);
> - debugfs_remove(bt->dropped_file);
> relay_close(bt->rchan);
> debugfs_remove(bt->dir);
> free_percpu(bt->sequence);
> @@ -544,10 +542,8 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
> INIT_LIST_HEAD(&bt->running_list);
>
> ret = -EIO;
> - bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
> - &blk_dropped_fops);
> -
> - bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
> + debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
> + debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
>
> bt->rchan = relay_open("trace", dir, buts->buf_size,
> buts->buf_nr, &blk_relay_callbacks, bt);