linux-kernel - Re: Linux 5.19-rc7 liburing test `poll-mshot-overflow.t` and `read-write.t` fail

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Message-ID: <3761ef37-85fc-de81-b211-39eaf3fe2362@gnuweeb.org>
Date:   Thu, 21 Jul 2022 20:08:19 +0700
From:   Ammar Faizi <ammarfaizi2@...weeb.org>
To:     Dylan Yudaken <dylany@...com>
Cc:     Jens Axboe <axboe@...nel.dk>,
        Pavel Begunkov <asml.silence@...il.com>,
        Fernanda Ma'rouf <fernandafmr12@...weeb.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        io-uring Mailing List <io-uring@...r.kernel.org>,
        GNU/Weeb Mailing List <gwml@...r.gnuweeb.org>
Subject: Re: Linux 5.19-rc7 liburing test `poll-mshot-overflow.t` and
 `read-write.t` fail

On 7/21/22 7:05 PM, Dylan Yudaken wrote:
> It seems to be a problem with blocking reads, buffer select and READV.
> My guess is that ext4/xfs are not blocking.
> 
> in b66e65f41426 ("io_uring: never call io_buffer_select() for a buffer
> re-select"), this line was added in __io_iov_buffer_select
> 
> -       iov[0].iov_len = len;
> +       req->rw.len = iov[0].iov_len = len;
> 
> Basically stashing the buffer length in rw.len. The problem is that the
> next time around that breaks at
> 
>          if (req->rw.len != 1)
>                  return -EINVAL;
> 
> 
> The below fixes it as an example, but it's not great. Maybe someone can
> figure out a better patch? Otherwise I can try tomorrow:

It's 8:05 PM from my end. I'll try to play with your patch after dinner
while waiting for others say something.

-- 
Ammar Faizi