net/txgbe: fix build by simplifying xstats return

When DPDK is compiled with gcc 7.5 with the optimization level set to 1
gcc sees the 'offset' variable in txgbe_ethdev.c as possibly being
uninitialised.
The 'txgbe_get_offset_by_id()' return value, "-(int)(id + 1)", seems
confusing gcc that it assumes '0' can be returned in the failure case.
To correct this the return statement for error case in
'txgbe_get_offset_by_id()' is simplified to return '-1'.

Fixes: 91fe49c87d76 ("net/txgbe: support device xstats")

Signed-off-by: Conor Walsh <conor.walsh@intel.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>

diff --git a/drivers/net/txgbe/txgbe_ethdev.c b/drivers/net/txgbe/txgbe_ethdev.c
index 9f53360..f8dffe1 100644 (file)
--- a/drivers/net/txgbe/txgbe_ethdev.c
+++ b/drivers/net/txgbe/txgbe_ethdev.c
@@ -2140,9 +2140,8 @@ txgbe_get_offset_by_id(uint32_t id, uint32_t *offset)
                        nb * (TXGBE_NB_QP_STATS * sizeof(uint64_t));
                return 0;
        }
-       id -= TXGBE_NB_QP_STATS * TXGBE_MAX_QP;
 
-       return -(int)(id + 1);
+       return -1;
 }
 
 static int txgbe_dev_xstats_get_names(struct rte_eth_dev *dev,