net/tls: Replace TLS_RX_SYNC_RUNNING with RCU

RCU synchronization is guaranteed to finish in finite time, unlike a
busy loop that polls a flag. This patch is a preparation for the bugfix
in the next patch, where the same synchronize_net() call will also be
used to sync with the TX datapath.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/tls.h b/include/net/tls.h
index 3eccb525e8f7954c43cec1b8c4212c903a35e76e..6531ace2a68bd1878f0e86327b1ad6ebc8a1ac69 100644 (file)
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -193,7 +193,6 @@ struct tls_offload_context_tx {
        (sizeof(struct tls_offload_context_tx) + TLS_DRIVER_STATE_SIZE_TX)
 
 enum tls_context_flags {
-       TLS_RX_SYNC_RUNNING = 0,
        /* Unlike RX where resync is driven entirely by the core in TX only
         * the driver knows when things went out of sync, so we need the flag
         * to be atomic.

diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index 76a6f8c2eec4bf2a71a4e02d9b598f702c488819..171752cd6910247bd5b3664700dbe06bd7bc36e3 100644 (file)
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -680,15 +680,13 @@ static void tls_device_resync_rx(struct tls_context *tls_ctx,
        struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
        struct net_device *netdev;
 
-       if (WARN_ON(test_and_set_bit(TLS_RX_SYNC_RUNNING, &tls_ctx->flags)))
-               return;
-
        trace_tls_device_rx_resync_send(sk, seq, rcd_sn, rx_ctx->resync_type);
+       rcu_read_lock();
        netdev = READ_ONCE(tls_ctx->netdev);
        if (netdev)
                netdev->tlsdev_ops->tls_dev_resync(netdev, sk, seq, rcd_sn,
                                                   TLS_OFFLOAD_CTX_DIR_RX);
-       clear_bit_unlock(TLS_RX_SYNC_RUNNING, &tls_ctx->flags);
+       rcu_read_unlock();
        TLS_INC_STATS(sock_net(sk), LINUX_MIB_TLSRXDEVICERESYNC);
 }
 
@@ -1300,9 +1298,7 @@ static int tls_device_down(struct net_device *netdev)
                        netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
                                                        TLS_OFFLOAD_CTX_DIR_RX);
                WRITE_ONCE(ctx->netdev, NULL);
-               smp_mb__before_atomic(); /* pairs with test_and_set_bit() */
-               while (test_bit(TLS_RX_SYNC_RUNNING, &ctx->flags))
-                       usleep_range(10, 200);
+               synchronize_net();
                dev_put(netdev);
                list_del_init(&ctx->list);