Re: io_uring_enter() with opcode IORING_OP_RECV ignores MSG_WAITALL in msg_flags

From: Jens Axboe
Date: Wed Mar 23 2022 - 08:19:17 EST


On 3/23/22 4:31 AM, Constantine Gavrilov wrote:
> I get partial receives on TCP socket, even though I specify
> MSG_WAITALL with IORING_OP_RECV opcode. Looking at tcpdump in
> wireshark, I see entire reassambled packet (+4k), so it is not a
> disconnect. The MTU is smaller than 4k.
>
> From the mailing list history, looks like this was discussed before
> and it seems the fix was supposed to be in. Can someone clarify the
> expected behavior?
>
> I do not think rsvmsg() has this issue.

Do you have a test case? I added the io-uring list, that's the
appropriate forum for this kind of discussion.

--
Jens Axboe