[PATCH 5/5] net/tls: implement ->read_sock()

[Paolo Abeni]

On Mon, 2023-07-03 at 11:04 +0200, Hannes Reinecke wrote:
> Implement ->read_sock() function for use with nvme-tcp.
> 
> Signed-off-by: Hannes Reinecke <hare at suse.de>
> Reviewed-by: Sagi Grimberg <sagi at grimberg.me>
> Cc: Boris Pismenny <boris.pismenny at gmail.com>
> Cc: Jakub Kicinski <kuba at kernel.org>
> Cc: netdev at vger.kernel.org
> ---
>  net/tls/tls.h      |  2 ++
>  net/tls/tls_main.c |  2 ++
>  net/tls/tls_sw.c   | 78 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 82 insertions(+)
> 
> diff --git a/net/tls/tls.h b/net/tls/tls.h
> index 86cef1c68e03..7e4d45537deb 100644
> --- a/net/tls/tls.h
> +++ b/net/tls/tls.h
> @@ -110,6 +110,8 @@ bool tls_sw_sock_is_readable(struct sock *sk);
>  ssize_t tls_sw_splice_read(struct socket *sock, loff_t *ppos,
>  			   struct pipe_inode_info *pipe,
>  			   size_t len, unsigned int flags);
> +int tls_sw_read_sock(struct sock *sk, read_descriptor_t *desc,
> +		     sk_read_actor_t read_actor);
>  
>  int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
>  void tls_device_splice_eof(struct socket *sock);
> diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
> index b6896126bb92..7dbb8cd8f809 100644
> --- a/net/tls/tls_main.c
> +++ b/net/tls/tls_main.c
> @@ -962,10 +962,12 @@ static void build_proto_ops(struct proto_ops ops[TLS_NUM_CONFIG][TLS_NUM_CONFIG]
>  	ops[TLS_BASE][TLS_SW  ] = ops[TLS_BASE][TLS_BASE];
>  	ops[TLS_BASE][TLS_SW  ].splice_read	= tls_sw_splice_read;
>  	ops[TLS_BASE][TLS_SW  ].poll		= tls_sk_poll;
> +	ops[TLS_BASE][TLS_SW  ].read_sock	= tls_sw_read_sock;
>  
>  	ops[TLS_SW  ][TLS_SW  ] = ops[TLS_SW  ][TLS_BASE];
>  	ops[TLS_SW  ][TLS_SW  ].splice_read	= tls_sw_splice_read;
>  	ops[TLS_SW  ][TLS_SW  ].poll		= tls_sk_poll;
> +	ops[TLS_SW  ][TLS_SW  ].read_sock	= tls_sw_read_sock;
>  
>  #ifdef CONFIG_TLS_DEVICE
>  	ops[TLS_HW  ][TLS_BASE] = ops[TLS_BASE][TLS_BASE];
> diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
> index d0636ea13009..dbf1c8a71f61 100644
> --- a/net/tls/tls_sw.c
> +++ b/net/tls/tls_sw.c
> @@ -2202,6 +2202,84 @@ ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
>  	goto splice_read_end;
>  }
>  
> +int tls_sw_read_sock(struct sock *sk, read_descriptor_t *desc,
> +		     sk_read_actor_t read_actor)
> +{
> +	struct tls_context *tls_ctx = tls_get_ctx(sk);
> +	struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
> +	struct strp_msg *rxm = NULL;
> +	struct tls_msg *tlm;
> +	struct sk_buff *skb;
> +	ssize_t copied = 0;
> +	int err, used;
> +
> +	err = tls_rx_reader_acquire(sk, ctx, true);
> +	if (err < 0)
> +		return err;
> +	if (!skb_queue_empty(&ctx->rx_list)) {
> +		skb = __skb_dequeue(&ctx->rx_list);
> +	} else {
> +		struct tls_decrypt_arg darg;
> +
> +		err = tls_rx_rec_wait(sk, NULL, true, true);
> +		if (err <= 0) {
> +			tls_rx_reader_release(sk, ctx);
> +			return err;

You can replace the 2 lines above with:

			goto read_sock_end;

> +		}
> +
> +		memset(&darg.inargs, 0, sizeof(darg.inargs));
> +
> +		err = tls_rx_one_record(sk, NULL, &darg);
> +		if (err < 0) {
> +			tls_err_abort(sk, -EBADMSG);
> +			tls_rx_reader_release(sk, ctx);
> +			return err;

Same here.

> +		}
> +
> +		tls_rx_rec_done(ctx);
> +		skb = darg.skb;
> +	}
> +
> +	do {
> +		rxm = strp_msg(skb);
> +		tlm = tls_msg(skb);
> +
> +		/* read_sock does not support reading control messages */
> +		if (tlm->control != TLS_RECORD_TYPE_DATA) {
> +			err = -EINVAL;
> +			goto read_sock_requeue;
> +		}
> +
> +		used = read_actor(desc, skb, rxm->offset, rxm->full_len);
> +		if (used <= 0) {
> +			err = used;
> +			goto read_sock_end;
> +		}
> +
> +		copied += used;
> +		if (used < rxm->full_len) {
> +			rxm->offset += used;
> +			rxm->full_len -= used;
> +			if (!desc->count)
> +				goto read_sock_requeue;
> +		} else {
> +			consume_skb(skb);
> +			if (desc->count && !skb_queue_empty(&ctx->rx_list))
> +				skb = __skb_dequeue(&ctx->rx_list);
> +			else
> +				skb = NULL;
> +		}
> +	} while (skb);
> +
> +read_sock_end:
> +	tls_rx_reader_release(sk, ctx);
> +	return copied ? : err;

WRT the return value, I think you should look at tcp_read_sock() as the
reference. The above LGTM. Some ->read_sock() callers ignore the  
return value due to the specific 'read_actor' callback used.

WRT the deadlock you see, try to run your tests with lockdep enabled,
it should provide valuable information on the deadlock cause, if any.

Cheers,

Paolo