Re: [PATCH 1/3] net: Remove support for AIO on sockets

[Jens Axboe <axboe@kernel.dk>]

On 5/25/26 2:03 AM, Christoph Hellwig wrote:
> On Sat, May 23, 2026 at 03:43:02PM -0400, Demi Marie Obenour via B4 Relay wrote:
>> From: Demi Marie Obenour <demiobenour@gmail.com>
>>
>> The only user of msg->msg_iocb was AF_ALG, but that's deprecated.
>> It can be removed entirely at the cost of only supporting synchronous
>> operations.  This doesn't break userspace, which will silently block
>> (for a bounded amount of time) in io_submit instead of operating
>> asynchronously.
>>
>> This also makes struct msghdr smaller, helping every other caller of
>> sendmsg().
> 
> So we just had a discussion at LLC about how networking needs to support
> AIO better for zero copy.
> 
> The current TCP zerocopy implementation provides completion notification
> through the socket error code, which is freaking weird and doesn't
> integrate well with either io_uring or in-kernel callers.

We already have that via io_uring, and without needing msg_kiocb or the
(very) weird socket error code retrieving.

-- 
Jens Axboe