[dpdk-dev] [PATCH] net/thunderx: fix build with gcc optimization on

[Ferruh Yigit]

build error gcc version 6.3.1 20161221 (Red Hat 6.3.1-1),
with EXTRA_CFLAGS="-O3":

.../drivers/net/thunderx/nicvf_ethdev.c:907:9:
   error: ‘txq’ may be used uninitialized in this function
   [-Werror=maybe-uninitialized]
  if (txq->pool_free == nicvf_single_pool_free_xmited_buffers)
      ~~~^~~~~~~~~~~
.../drivers/net/thunderx/nicvf_ethdev.c:886:20:
   note: ‘txq’ was declared here
  struct nicvf_txq *txq;
                    ^~~

Same error on function 'nicvf_eth_dev_init' and 'nicvf_dev_start', it
seems 'nicvf_set_tx_function' inlined when optimization enabled.

Initialize the txq and add NULL check before using it to fix.

Fixes: 7413feee662d ("net/thunderx: add device start/stop and close")
Cc: stable at dpdk.org

Reported-by: Richard Walsh <richard.walsh at intel.com>
Signed-off-by: Ferruh Yigit <ferruh.yigit at intel.com>
---

Btw, no compiler optimization enabled, only nicvf_rxtx.c has -Ofast,
is this intentional?
---
 drivers/net/thunderx/nicvf_ethdev.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/thunderx/nicvf_ethdev.c b/drivers/net/thunderx/nicvf_ethdev.c
index 99fcd516b..4ab1bfbe6 100644
--- a/drivers/net/thunderx/nicvf_ethdev.c
+++ b/drivers/net/thunderx/nicvf_ethdev.c
@@ -883,7 +883,7 @@ nicvf_dev_tx_queue_release(void *sq)
 static void
 nicvf_set_tx_function(struct rte_eth_dev *dev)
 {
-	struct nicvf_txq *txq;
+	struct nicvf_txq *txq = NULL;
 	size_t i;
 	bool multiseg = false;
 
@@ -904,6 +904,9 @@ nicvf_set_tx_function(struct rte_eth_dev *dev)
 		dev->tx_pkt_burst = nicvf_xmit_pkts;
 	}
 
+	if (!txq)
+		return;
+
 	if (txq->pool_free == nicvf_single_pool_free_xmited_buffers)
 		PMD_DRV_LOG(DEBUG, "Using single-mempool tx free method");
 	else
-- 
2.17.1