From: Jakub Kicinski <kuba@kernel•org>
To: Sagi Grimberg <sagi@grimberg•me>
Cc: Hannes Reinecke <hare@suse•de>, Christoph Hellwig <hch@lst•de>,
Keith Busch <kbusch@kernel•org>,
linux-nvme@lists•infradead.org,
Eric Dumazet <edumazet@google•com>,
Paolo Abeni <pabeni@redhat•com>,
netdev@vger•kernel.org, Boris Pismenny <boris.pismenny@gmail•com>
Subject: Re: [PATCH 4/4] net/tls: implement ->read_sock()
Date: Tue, 20 Jun 2023 10:08:43 -0700 [thread overview]
Message-ID: <20230620100843.19569d60@kernel.org> (raw)
In-Reply-To: <5bbb6ce4-a251-a357-3efc-9e899e470b9c@grimberg.me>
On Tue, 20 Jun 2023 16:21:22 +0300 Sagi Grimberg wrote:
> > + err = tls_rx_reader_lock(sk, ctx, true);
> > + if (err < 0)
> > + return err;
>
> Unlike recvmsg or splice_read, the caller of read_sock is assumed to
> have the socket locked, and tls_rx_reader_lock also calls lock_sock,
> how is this not a deadlock?
Yeah :|
> I'm not exactly clear why the lock is needed here or what is the subtle
> distinction between tls_rx_reader_lock and what lock_sock provides.
It's a bit of a workaround for the consistency of the data stream.
There's bunch of state in the TLS ULP and waiting for mem or data
releases and re-takes the socket lock. So to stop the flow annoying
corner case races I slapped a lock around all of the reader.
IMHO depending on the socket lock for anything non-trivial and outside
of the socket itself is a bad idea in general.
The immediate need at the time was that if you did a read() and someone
else did a peek() at the same time from a stream of A B C D you may read
A D B C.
next prev parent reply other threads:[~2023-06-20 17:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-20 10:28 [PATCHv5 0/4] net/tls: fixes for NVMe-over-TLS Hannes Reinecke
2023-06-20 10:28 ` [PATCH 1/4] net/tls: handle MSG_EOR for tls_sw TX flow Hannes Reinecke
2023-06-20 10:28 ` [PATCH 2/4] net/tls: handle MSG_EOR for tls_device " Hannes Reinecke
2023-06-20 17:12 ` Sabrina Dubroca
2023-06-21 6:09 ` Hannes Reinecke
2023-06-20 10:28 ` [PATCH 3/4] selftests/net/tls: add test for MSG_EOR Hannes Reinecke
2023-06-20 10:28 ` [PATCH 4/4] net/tls: implement ->read_sock() Hannes Reinecke
2023-06-20 13:21 ` Sagi Grimberg
2023-06-20 17:08 ` Jakub Kicinski [this message]
2023-06-21 6:44 ` Hannes Reinecke
2023-06-21 8:39 ` Sagi Grimberg
2023-06-21 9:08 ` Hannes Reinecke
2023-06-21 9:49 ` Sagi Grimberg
2023-06-21 19:31 ` Jakub Kicinski
-- strict thread matches above, loose matches on Subject: below --
2023-06-14 6:22 [PATCHv4 0/4] net/tls: fixes for NVMe-over-TLS Hannes Reinecke
2023-06-14 6:22 ` [PATCH 4/4] net/tls: implement ->read_sock() Hannes Reinecke
2023-06-17 6:28 ` Jakub Kicinski
2023-06-17 14:08 ` Simon Horman
2023-06-19 8:16 ` Dan Carpenter
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