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From: Al Viro <viro@zeniv.linux.org.uk>
To: Alice Ryhl <aliceryhl@google.com>
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Miguel Ojeda" <ojeda@kernel.org>,
	"Christian Brauner" <brauner@kernel.org>,
	"Jan Kara" <jack@suse.cz>, "Boqun Feng" <boqun.feng@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <benno.lossin@proton.me>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Trevor Gross" <tmgross@umich.edu>,
	rust-for-linux@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] rust: file: add f_pos and set_f_pos
Date: Thu, 26 Sep 2024 23:08:21 +0100	[thread overview]
Message-ID: <20240926220821.GP3550746@ZenIV> (raw)
In-Reply-To: <20240926-b4-miscdevice-v1-2-7349c2b2837a@google.com>

On Thu, Sep 26, 2024 at 02:58:56PM +0000, Alice Ryhl wrote:
> Add accessors for the file position. Most of the time, you should not
> use these methods directly, and you should instead use a guard for the
> file position to prove that you hold the fpos lock. However, under
> limited circumstances, files are allowed to choose a different locking
> strategy for their file position. These accessors can be used to handle
> that case.
> 
> For now, these accessors are the only way to access the file position
> within the llseek and read_iter callbacks.

You really should not do that within ->read_iter().  If your method
does that, it has the wrong signature.

If nothing else, it should be usable for preadv(2), so what file position
are you talking about?

  reply	other threads:[~2024-09-26 22:08 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-26 14:58 [PATCH 0/3] Miscdevices in Rust Alice Ryhl
2024-09-26 14:58 ` [PATCH 1/3] rust: types: add Opaque::try_ffi_init Alice Ryhl
2024-09-27  9:00   ` Fiona Behrens
2024-09-26 14:58 ` [PATCH 2/3] rust: file: add f_pos and set_f_pos Alice Ryhl
2024-09-26 22:08   ` Al Viro [this message]
2024-09-26 22:47     ` Al Viro
2024-09-26 22:52       ` Al Viro
2024-09-27  6:56       ` Alice Ryhl
2024-09-27 19:38         ` Al Viro
2024-10-01  8:20           ` Alice Ryhl
2024-09-27  6:48     ` Alice Ryhl
2024-09-27  7:32   ` Christian Brauner
2024-09-26 14:58 ` [PATCH 3/3] rust: miscdevice: add abstraction for defining miscdevices Alice Ryhl
2024-09-26 15:05 ` [PATCH 0/3] Miscdevices in Rust Greg Kroah-Hartman
2024-09-26 15:11   ` Miguel Ojeda
2024-09-26 15:20   ` Alice Ryhl
2024-09-26 15:36     ` Greg Kroah-Hartman
2024-09-26 18:58 ` Benno Lossin
2024-09-27  6:04   ` Greg Kroah-Hartman

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