Re: [PATCH v2] nvme/tcp: handle tls partially sent records in write_space()

[Wilfred Mallawa <wilfred.opensource@gmail.com>]

On Fri, 2025-10-10 at 09:03 +0200, Hannes Reinecke wrote:
> On 10/10/25 06:25, Wilfred Mallawa wrote:
> > From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
> > 
> > With TLS enabled, records that are encrypted and appended to TLS TX
> > list can fail to see a retry if the underlying TCP socket is busy,
> > for
> > example, hitting an EAGAIN from tcp_sendmsg_locked(). This is not
> > known
> > to the NVMe TCP driver, as the TLS layer successfully generated a
> > record.
> > 
> > Typically, the TLS write_space() callback would ensure such records
> > are
> > retried, but in the NVMe TCP Host driver, write_space() invokes
> > nvme_tcp_write_space(). This causes a partially sent record in the
> > TLS TX
> > list to timeout after not being retried.
> > 
> > This patch fixes the above by calling queue->write_space(), which
> > calls
> > into the TLS layer to retry any pending records.
> > 
> > Fixes: be8e82caa685 ("nvme-tcp: enable TLS handshake upcall")
> > Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
> > ---
> > V2:
> >      - Unconditionally invoke TLS write_space(). This means we
> > don't need
> >        to export tls_is_partially_sent_record()
> > ---
> > drivers/nvme/host/tcp.c | 5 +++++
> >   1 file changed, 5 insertions(+)
> > 
> > diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> > index 1413788ca7d5..6016510577bd 100644
> > --- a/drivers/nvme/host/tcp.c
> > +++ b/drivers/nvme/host/tcp.c
> > @@ -1079,8 +1079,13 @@ static void nvme_tcp_write_space(struct sock
> > *sk)
> >   
> >   	read_lock_bh(&sk->sk_callback_lock);
> >   	queue = sk->sk_user_data;
> > +
> >   	if (likely(queue && sk_stream_is_writeable(sk))) {
> >   		clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
> > +		/* Ensure pending TLS partial records are retried
> > */
> > +		if (nvme_tcp_queue_tls(queue))
> > +			queue->write_space(sk);
> > +
> >   		queue_work_on(queue->io_cpu, nvme_tcp_wq, &queue-
> > >io_work);
> >   	}
> >   	read_unlock_bh(&sk->sk_callback_lock);
> 
> Minus the whitespace change:
> 
> Reviewed-by: Hannes Reinecke <hare@suse.de>

Ah only just saw this, sent a V3 with the white-space fixed. Thanks for
the review!

Regards,
Wilfred

> 
> Cheers,
> 
> Hannes