Subject: [PATCH 15/24] net/tls: don't pay attention to sk_write_pending when pushing partial records

From: Jakub Kicinski <[email-masked]>
Date: Tue, 5 Nov 2019 14:24:34 -0800

[ Upstream commit 02b1fa07bb58f5d1f349b5b09eb936739a7b20fc ]

sk_write_pending being not zero does not guarantee that partial
record will be pushed. If the thread waiting for memory times out
the pending record may get stuck.

In case of tls_device there is no path where parial record is
set and writer present in the first place. Partial record is
set only in tls_push_sg() and tls_push_sg() will return an
error immediately. All tls_device callers of tls_push_sg()
will return (and not wait for memory) if it failed.

Fixes: a42055e8d2c3 ("net/tls: Add support for async encryption of records for performance")
Signed-off-by: Jakub Kicinski <[email-masked]>
Reviewed-by: Simon Horman <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/tls/tls_device.c | 4 +++-
 net/tls/tls_sw.c     | 9 +++------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index 43922d86e510..479ebc0ed866 100644
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -575,9 +575,11 @@ static int tls_device_push_pending_record(struct sock *sk, int flags)
 
 void tls_device_write_space(struct sock *sk, struct tls_context *ctx)
 {
-	if (!sk->sk_write_pending && tls_is_partially_sent_record(ctx)) {
+	if (tls_is_partially_sent_record(ctx)) {
 		gfp_t sk_allocation = sk->sk_allocation;
 
+		WARN_ON_ONCE(sk->sk_write_pending);
+
 		sk->sk_allocation = GFP_ATOMIC;
 		tls_push_partial_record(sk, ctx,
 					MSG_DONTWAIT | MSG_NOSIGNAL |
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 91d21b048a9b..b751adc3876c 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2182,12 +2182,9 @@ void tls_sw_write_space(struct sock *sk, struct tls_context *ctx)
 	struct tls_sw_context_tx *tx_ctx = tls_sw_ctx_tx(ctx);
 
 	/* Schedule the transmission if tx list is ready */
-	if (is_tx_ready(tx_ctx) && !sk->sk_write_pending) {
-		/* Schedule the transmission */
-		if (!test_and_set_bit(BIT_TX_SCHEDULED,
-				      &tx_ctx->tx_bitmask))
-			schedule_delayed_work(&tx_ctx->tx_work.work, 0);
-	}
+	if (is_tx_ready(tx_ctx) &&
+	    !test_and_set_bit(BIT_TX_SCHEDULED, &tx_ctx->tx_bitmask))
+		schedule_delayed_work(&tx_ctx->tx_work.work, 0);
 }
 
 void tls_sw_strparser_arm(struct sock *sk, struct tls_context *tls_ctx)
-- 
2.20.1