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Date:   Mon, 16 Oct 2023 09:26:46 +0200
From:   Sascha Hauer <sha@pengutronix.de>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Boris Pismenny <borisp@nvidia.com>, netdev@vger.kernel.org,
        John Fastabend <john.fastabend@gmail.com>,
        linux-kernel@vger.kernel.org, io-uring@vger.kernel.org,
        kernel@pengutronix.de, Jakub Kicinski <kuba@kernel.org>,
        Pavel Begunkov <asml.silence@gmail.com>
Subject: Re: Problem with io_uring splice and KTLS
Message-ID: <20231016072646.GV3359458@pengutronix.de>
References: <20231010141932.GD3114228@pengutronix.de>
 <d729781a-3d12-423b-973e-c16fdbcbb60b@kernel.dk>
 <20231012133407.GA3359458@pengutronix.de>
 <f39ef992-4789-4c30-92ef-e3114a31d5c7@kernel.dk>
 <20231013054716.GG3359458@pengutronix.de>
 <a9dd11d9-b5b8-456d-b8b6-12257e2924ab@kernel.dk>
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On Fri, Oct 13, 2023 at 07:45:55AM -0600, Jens Axboe wrote:
> On 10/12/23 11:47 PM, Sascha Hauer wrote:
> > On Thu, Oct 12, 2023 at 07:45:07PM -0600, Jens Axboe wrote:
> >> On 10/12/23 7:34 AM, Sascha Hauer wrote:
> >>> In case you don't have encryption hardware you can create an
> >>> asynchronous encryption module using cryptd. Compile a kernel with
> >>> CONFIG_CRYPTO_USER_API_AEAD and CONFIG_CRYPTO_CRYPTD and start the
> >>> webserver with the '-c' option. /proc/crypto should then contain an
> >>> entry with:
> >>>
> >>>  name         : gcm(aes)
> >>>  driver       : cryptd(gcm_base(ctr(aes-generic),ghash-generic))
> >>>  module       : kernel
> >>>  priority     : 150
> >>
> >> I did a bit of prep work to ensure I had everything working for when
> >> there's time to dive into it, but starting it with -c doesn't register
> >> this entry. Turns out the bind() in there returns -1/ENOENT.
> > 
> > Yes, that happens here as well, that's why I don't check for the error
> > in the bind call. Nevertheless it has the desired effect that the new
> > algorithm is registered and used from there on. BTW you only need to
> > start the webserver once with -c. If you start it repeatedly with -c a
> > new gcm(aes) instance is registered each time.
> 
> Gotcha - I wasn't able to trigger the condition, which is why I thought
> perhaps I was missing something.
> 
> Can you try the below patch and see if that makes a difference? I'm not
> quite sure why it would since you said it triggers with DEFER_TASKRUN as
> well, and for that kind of notification, you should never hit the paths
> you have detailed in the debug patch.

I can confirm that this patch makes it work for me. I tested with both
software cryptd and also with my original CAAM encryption workload.
IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN is not needed.
Both my simple webserver and the original C++ Webserver from our
customer are now working without problems.

Do you think there is a chance getting this change upstream? I'm a bit
afraid the code originally uses signal_pending() instead of
task_sigpending() for a good reason.

Sascha

> 
> diff --git a/net/core/stream.c b/net/core/stream.c
> index f5c4e47df165..a9a196587254 100644
> --- a/net/core/stream.c
> +++ b/net/core/stream.c
> @@ -67,7 +67,7 @@ int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
>  			return -EPIPE;
>  		if (!*timeo_p)
>  			return -EAGAIN;
> -		if (signal_pending(tsk))
> +		if (task_sigpending(tsk))
>  			return sock_intr_errno(*timeo_p);
>  
>  		add_wait_queue(sk_sleep(sk), &wait);
> @@ -103,7 +103,7 @@ void sk_stream_wait_close(struct sock *sk, long timeout)
>  		do {
>  			if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk), &wait))
>  				break;
> -		} while (!signal_pending(current) && timeout);
> +		} while (!task_sigpending(current) && timeout);
>  
>  		remove_wait_queue(sk_sleep(sk), &wait);
>  	}
> @@ -134,7 +134,7 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
>  			goto do_error;
>  		if (!*timeo_p)
>  			goto do_eagain;
> -		if (signal_pending(current))
> +		if (task_sigpending(current))
>  			goto do_interrupted;
>  		sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
>  		if (sk_stream_memory_free(sk) && !vm_wait)
> 
> -- 
> Jens Axboe
> 
> 

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