linux-kernel - Re: [PATCH v5 4/4] rust: samples: Add debugfs sample

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aCUVuXO_jORqlxwr@pollux>
Date: Thu, 15 May 2025 00:14:17 +0200
From: Danilo Krummrich <dakr@...nel.org>
To: Matthew Maurer <mmaurer@...gle.com>
Cc: Benno Lossin <lossin@...nel.org>, Miguel Ojeda <ojeda@...nel.org>,
	Alex Gaynor <alex.gaynor@...il.com>,
	Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>,
	Björn Roy Baron <bjorn3_gh@...tonmail.com>,
	Benno Lossin <benno.lossin@...ton.me>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Sami Tolvanen <samitolvanen@...gle.com>,
	Timur Tabi <ttabi@...dia.com>, linux-kernel@...r.kernel.org,
	rust-for-linux@...r.kernel.org
Subject: Re: [PATCH v5 4/4] rust: samples: Add debugfs sample

On Wed, May 14, 2025 at 03:08:21PM -0700, Matthew Maurer wrote:
> On Wed, May 14, 2025 at 2:54 AM Benno Lossin <lossin@...nel.org> wrote:
> > Another problem that only affects complicated debugfs structures is that
> > you would have to store all subdirs & files somewhere. If the structure
> > is dynamic and changes over the lifetime of the driver, then you'll need
> > a `Vec` or store the dirs in `Arc` or similar, leading to extra
> > allocations.
> 
> Yep, this is part of why I tried to follow the "Build it, then hold
> the needed handles to keep it alive" approach rather than keeping the
> entire structure around.

I already replied to that [1]:

"If it changes dynamically then it's pretty likely that we do not only want to
add entries dynamically, but also remove them, which implies that we need to be
able to drop them. So, I don't think that's a problem."

It is much more of a problem if we can't remove certain entries anymore without
removing all of them.

[1] https://lore.kernel.org/rust-for-linux/aCR9cD7OcSefeaUm@pollux/