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

[Wilfred Mallawa]

From: Wilfred Mallawa <wilfred.mallawa at 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 aims to address the above by first publically exposing
tls_is_partially_sent_record(), then, using this in the NVMe TCP host
driver to invoke the TLS write_space() handler where appropriate.

Signed-off-by: Wilfred Mallawa <wilfred.mallawa at wdc.com>
Fixes: be8e82caa685 ("nvme-tcp: enable TLS handshake upcall")
---
 drivers/nvme/host/tcp.c | 8 ++++++++
 include/net/tls.h       | 5 +++++
 net/tls/tls.h           | 5 -----
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 1413788ca7d5..e3d02c33243b 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1076,11 +1076,18 @@ static void nvme_tcp_data_ready(struct sock *sk)
 static void nvme_tcp_write_space(struct sock *sk)
 {
 	struct nvme_tcp_queue *queue;
+	struct tls_context *ctx = tls_get_ctx(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) &&
+		    tls_is_partially_sent_record(ctx))
+			queue->write_space(sk);
+
 		queue_work_on(queue->io_cpu, nvme_tcp_wq, &queue->io_work);
 	}
 	read_unlock_bh(&sk->sk_callback_lock);
@@ -1306,6 +1313,7 @@ static int nvme_tcp_try_send_ddgst(struct nvme_tcp_request *req)
 static int nvme_tcp_try_send(struct nvme_tcp_queue *queue)
 {
 	struct nvme_tcp_request *req;
+	struct tls_context *ctx = tls_get_ctx(queue->sock->sk);
 	unsigned int noreclaim_flag;
 	int ret = 1;
 
diff --git a/include/net/tls.h b/include/net/tls.h
index 857340338b69..9c61a2de44bf 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -373,6 +373,11 @@ static inline struct tls_context *tls_get_ctx(const struct sock *sk)
 	return (__force void *)icsk->icsk_ulp_data;
 }
 
+static inline bool tls_is_partially_sent_record(struct tls_context *ctx)
+{
+	return !!ctx->partially_sent_record;
+}
+
 static inline struct tls_sw_context_rx *tls_sw_ctx_rx(
 		const struct tls_context *tls_ctx)
 {
diff --git a/net/tls/tls.h b/net/tls/tls.h
index 2f86baeb71fc..7839a2effe31 100644
--- a/net/tls/tls.h
+++ b/net/tls/tls.h
@@ -271,11 +271,6 @@ int tls_push_partial_record(struct sock *sk, struct tls_context *ctx,
 			    int flags);
 void tls_free_partial_record(struct sock *sk, struct tls_context *ctx);
 
-static inline bool tls_is_partially_sent_record(struct tls_context *ctx)
-{
-	return !!ctx->partially_sent_record;
-}
-
 static inline bool tls_is_pending_open_record(struct tls_context *tls_ctx)
 {
 	return tls_ctx->pending_open_record_frags;
-- 
2.51.0