[PATCH net v2 1/2] Revert "net/tls: avoid NULL-deref on resync during device removal"

[Jakub Kicinski <jakub.kicinski@netronome.com>]

This reverts commit 38030d7cb77963ba84cdbe034806e2b81245339f.
Unfortunately the RX resync may get called from soft IRQ,
so we can't take the rwsem to protect from the device
disappearing.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
 net/tls/tls_device.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index b95c408fd771..49b3a2ff8ef3 100644
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -553,8 +553,8 @@ void tls_device_write_space(struct sock *sk, struct tls_context *ctx)
 void handle_device_resync(struct sock *sk, u32 seq, u64 rcd_sn)
 {
 	struct tls_context *tls_ctx = tls_get_ctx(sk);
+	struct net_device *netdev = tls_ctx->netdev;
 	struct tls_offload_context_rx *rx_ctx;
-	struct net_device *netdev;
 	u32 is_req_pending;
 	s64 resync_req;
 	u32 req_seq;
@@ -568,15 +568,10 @@ void handle_device_resync(struct sock *sk, u32 seq, u64 rcd_sn)
 	is_req_pending = resync_req;
 
 	if (unlikely(is_req_pending) && req_seq == seq &&
-	    atomic64_try_cmpxchg(&rx_ctx->resync_req, &resync_req, 0)) {
-		seq += TLS_HEADER_SIZE - 1;
-		down_read(&device_offload_lock);
-		netdev = tls_ctx->netdev;
-		if (netdev)
-			netdev->tlsdev_ops->tls_dev_resync_rx(netdev, sk, seq,
-							      rcd_sn);
-		up_read(&device_offload_lock);
-	}
+	    atomic64_try_cmpxchg(&rx_ctx->resync_req, &resync_req, 0))
+		netdev->tlsdev_ops->tls_dev_resync_rx(netdev, sk,
+						      seq + TLS_HEADER_SIZE - 1,
+						      rcd_sn);
 }
 
 static int tls_device_reencrypt(struct sock *sk, struct sk_buff *skb)
-- 
2.21.0