net: Explicitly initialize u64_stats_sync structures for lockdep

In order to enable lockdep on seqcount/seqlock structures, we
must explicitly initialize any locks.

The u64_stats_sync structure, uses a seqcount, and thus we need
to introduce a u64_stats_init() function and use it to initialize
the structure.

This unfortunately adds a lot of fairly trivial initialization code
to a number of drivers. But the benefit of ensuring correctness makes
this worth while.

Because these changes are required for lockdep to be enabled, and the
changes are quite trivial, I've not yet split this patch out into 30-some
separate patches, as I figured it would be better to get the various
maintainers thoughts on how to best merge this change along with
the seqcount lockdep enablement.

Feedback would be appreciated!

Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: James Morris <jmorris@namei.org>
Cc: Jesse Gross <jesse@nicira.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mirko Lindner <mlindner@marvell.com>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Roger Luethi <rl@hellgate.ch>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Simon Horman <horms@verge.net.au>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Wensong Zhang <wensong@linux-vs.org>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/1381186321-4906-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 9 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 8cf44f2a8ccd..b6edb93a8fc1 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -1223,6 +1223,9 @@ static int igb_alloc_q_vector(struct igb_adapter *adapter,
                 ring->count = adapter->tx_ring_count;
                 ring->queue_index = txr_idx;
 
+                u64_stats_init(&ring->tx_syncp);
+                u64_stats_init(&ring->tx_syncp2);
+
                 /* assign ring to adapter */
                 adapter->tx_ring[txr_idx] = ring;
 
@@ -1256,6 +1259,8 @@ static int igb_alloc_q_vector(struct igb_adapter *adapter,
                 ring->count = adapter->rx_ring_count;
                 ring->queue_index = rxr_idx;
 
+                u64_stats_init(&ring->rx_syncp);
+
                 /* assign ring to adapter */
                 adapter->rx_ring[rxr_idx] = ring;
         }
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 0ade0cd5ef53..c1750364ddc0 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -4867,6 +4867,8 @@ int ixgbe_setup_tx_resources(struct ixgbe_ring *tx_ring)
         if (!tx_ring->tx_buffer_info)
                 goto err;
 
+        u64_stats_init(&tx_ring->syncp);
+
         /* round up to nearest 4K */
         tx_ring->size = tx_ring->count * sizeof(union ixgbe_adv_tx_desc);
         tx_ring->size = ALIGN(tx_ring->size, 4096);
@@ -4949,6 +4951,8 @@ int ixgbe_setup_rx_resources(struct ixgbe_ring *rx_ring)
         if (!rx_ring->rx_buffer_info)
                 goto err;
 
+        u64_stats_init(&rx_ring->syncp);
+
         /* Round up to nearest 4K */
         rx_ring->size = rx_ring->count * sizeof(union ixgbe_adv_rx_desc);
         rx_ring->size = ALIGN(rx_ring->size, 4096);