Re: [PATCH] fuse: don't set file->private_data in fuse_conn_waiting_read

From: Miklos Szeredi
Date: Fri Feb 14 2025 - 05:18:08 EST


On Tue, 4 Feb 2025 at 16:04, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
>
> I see no reason to set the private_data on the file to this value. Just
> grab the result of the atomic_read() and output it without setting
> private_data.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/fuse/control.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/fs/fuse/control.c b/fs/fuse/control.c
> index 2a730d88cc3bdb50ea1f8a3185faad5f05fc6e74..17ef07cf0c38e44bd7eadb3450bd53a8acc5e885 100644
> --- a/fs/fuse/control.c
> +++ b/fs/fuse/control.c
> @@ -49,18 +49,17 @@ static ssize_t fuse_conn_waiting_read(struct file *file, char __user *buf,
> {
> char tmp[32];
> size_t size;
> + int value;
>
> if (!*ppos) {
> - long value;
> struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
> if (!fc)
> return 0;
>
> value = atomic_read(&fc->num_waiting);
> - file->private_data = (void *)value;
> fuse_conn_put(fc);
> }

"value" is uninitialized if *ppos is non-zero.

I also wonder why this patch is an improvement (with the bug fixed)?

Thanks,
Mikos