Re: [PATCH v3 0/3] Rust scatterlist abstractions

From: "Qingsong Chen" <changxian.cqs@antgroup.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, 田洪亮 <tate.thl@antgroup.com>,
	"Miguel Ojeda" <ojeda@kernel.org>,
	"Alex Gaynor" <alex.gaynor@gmail.com>,
	"Wedson Almeida Filho" <wedsonaf@gmail.com>,
	"Boqun Feng" <boqun.feng@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <benno.lossin@proton.me>,
	rust-for-linux@vger.kernel.org
Subject: Re: [PATCH v3 0/3] Rust scatterlist abstractions
Date: Mon, 12 Jun 2023 15:03:14 +0800	[thread overview]
Message-ID: <5469fb25-e88a-b703-c0d9-204f0cbcab91@antgroup.com> (raw)
In-Reply-To: <2023061257-unbeaten-dropkick-a25c@gregkh>

On 6/12/23 1:38 PM, Greg KH wrote:
> On Mon, Jun 12, 2023 at 11:49:51AM +0800, Qingsong Chen wrote:
>> On 6/10/23 11:35 PM, Greg KH wrote:
>>> On Sat, Jun 10, 2023 at 05:33:47PM +0200, Greg KH wrote:
>>>> On Sat, Jun 10, 2023 at 06:49:06PM +0800, Qingsong Chen wrote:
>>>>> Hi All!
>>>>>
>>>>> This is a version of scatterlist abstractions for Rust drivers.
>>>>>
>>>>> Scatterlist is used for efficient management of memory buffers, which is
>>>>> essential for many kernel-level operations such as Direct Memory Access
>>>>> (DMA) transfers and crypto APIs.
>>>>>
>>>>> This patch should be a good start to introduce the crypto APIs for Rust
>>>>> drivers and to develop cipher algorithms in Rust later.
>>>>
>>>> I thought we were getting rid of the scatter list api for the crypto
>>>> drivers, so this shouldn't be needed going forward, right?  Why not just
>>>> use the direct apis instead?
>>>
>>> See https://lore.kernel.org/r/ZH2hgrV6po9dkxi+@gondor.apana.org.au for
>>> the details of that (sorry I forgot the link first time...)
>>
>> Thanks for the information. I agree that turning simple buffers into
>> sg-bufs is not a good idea. If I were implementing a new cipher
>> algorithm, I would definitely follow the `struct cipher_alg`, which
>> takes simple `u8 *` pointer as parameter. However, if we'd like to
>> utilize some existing ciphers, such as aead, we still need scatterlists
>> to construct an `aead_request` for further operations, util changes are
>> made to the underlying interface.
> 
> Why not make the changes to the C code first, and get those changes
> merged, making this patch series not needed at all?
> 

Yes, you're right. I believe Herbert would work on that. And I would
stop this patch series. Thanks.

Qingsong Chen