[dpdk-dev] [PATCH] net/mlx5: fix invalid network interface index value

[Adrien Mazarguil]

Network interface indices being unsigned, an invalid index or error is
normally expressed through a zero value (see if_nametoindex()).

mlx5_ifindex() has a signed return type for negative values in case of
error. Since mlx5_nl.c does not check for errors, these may be fed back as
invalid interfaces indices to subsequent system calls. This usage would
have been correct if mlx5_ifindex() returned a zero value instead.

This patch makes mlx5_ifindex() unsigned for convenience.

Fixes: ccdcba53a3f4 ("net/mlx5: use Netlink to add/remove MAC addresses")
Cc: Nelio Laranjeiro <nelio.laranje...@6wind.com>
Cc: sta...@dpdk.org

Signed-off-by: Adrien Mazarguil <adrien.mazarg...@6wind.com>
Acked-by: Nelio Laranjeiro <nelio.laranje...@6wind.com>
---
 drivers/net/mlx5/mlx5.h        |  2 +-
 drivers/net/mlx5/mlx5_ethdev.c | 20 ++++++++------------
 drivers/net/mlx5/mlx5_nl.c     |  6 +++---
 3 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
index db8a5fa01..25345baea 100644
--- a/drivers/net/mlx5/mlx5.h
+++ b/drivers/net/mlx5/mlx5.h
@@ -243,7 +243,7 @@ int mlx5_getenv_int(const char *);
 int mlx5_get_master_ifname(const struct rte_eth_dev *dev,
                           char (*ifname)[IF_NAMESIZE]);
 int mlx5_get_ifname(const struct rte_eth_dev *dev, char 
(*ifname)[IF_NAMESIZE]);
-int mlx5_ifindex(const struct rte_eth_dev *dev);
+unsigned int mlx5_ifindex(const struct rte_eth_dev *dev);
 int mlx5_ifreq(const struct rte_eth_dev *dev, int req, struct ifreq *ifr,
               int master);
 int mlx5_get_mtu(struct rte_eth_dev *dev, uint16_t *mtu);
diff --git a/drivers/net/mlx5/mlx5_ethdev.c b/drivers/net/mlx5/mlx5_ethdev.c
index 9cf2dc5f1..a1c1b50a6 100644
--- a/drivers/net/mlx5/mlx5_ethdev.c
+++ b/drivers/net/mlx5/mlx5_ethdev.c
@@ -245,24 +245,20 @@ mlx5_get_ifname(const struct rte_eth_dev *dev, char 
(*ifname)[IF_NAMESIZE])
  *   Pointer to Ethernet device.
  *
  * @return
- *   Interface index on success, a negative errno value otherwise and
- *   rte_errno is set.
+ *   Nonzero interface index on success, zero otherwise and rte_errno is set.
  */
-int
+unsigned int
 mlx5_ifindex(const struct rte_eth_dev *dev)
 {
        char ifname[IF_NAMESIZE];
-       unsigned int ret;
+       unsigned int ifindex;
 
-       ret = mlx5_get_ifname(dev, &ifname);
-       if (ret)
-               return ret;
-       ret = if_nametoindex(ifname);
-       if (ret == 0) {
+       if (mlx5_get_ifname(dev, &ifname))
+               return 0;
+       ifindex = if_nametoindex(ifname);
+       if (!ifindex)
                rte_errno = errno;
-               return -rte_errno;
-       }
-       return ret;
+       return ifindex;
 }
 
 /**
diff --git a/drivers/net/mlx5/mlx5_nl.c b/drivers/net/mlx5/mlx5_nl.c
index 008cd2c31..cc562dfc9 100644
--- a/drivers/net/mlx5/mlx5_nl.c
+++ b/drivers/net/mlx5/mlx5_nl.c
@@ -365,7 +365,7 @@ mlx5_nl_mac_addr_list(struct rte_eth_dev *dev, struct 
ether_addr (*mac)[],
                      int *mac_n)
 {
        struct priv *priv = dev->data->dev_private;
-       int iface_idx = mlx5_ifindex(dev);
+       unsigned int iface_idx = mlx5_ifindex(dev);
        struct {
                struct nlmsghdr hdr;
                struct ifinfomsg ifm;
@@ -424,7 +424,7 @@ mlx5_nl_mac_addr_modify(struct rte_eth_dev *dev, struct 
ether_addr *mac,
                        int add)
 {
        struct priv *priv = dev->data->dev_private;
-       int iface_idx = mlx5_ifindex(dev);
+       unsigned int iface_idx = mlx5_ifindex(dev);
        struct {
                struct nlmsghdr hdr;
                struct ndmsg ndm;
@@ -603,7 +603,7 @@ static int
 mlx5_nl_device_flags(struct rte_eth_dev *dev, uint32_t flags, int enable)
 {
        struct priv *priv = dev->data->dev_private;
-       int iface_idx = mlx5_ifindex(dev);
+       unsigned int iface_idx = mlx5_ifindex(dev);
        struct {
                struct nlmsghdr hdr;
                struct ifinfomsg ifi;
-- 
2.11.0