net/mlx5: fix HW counters path in switchdev mode

When debugging performance of a DPDK application the user may
need to view the different statistics of DPDK (for example out_of_buffer)
This can be enabled by using testpmd command 'show port xstats
<port_id>' for example.

The current implementation assumes legacy mode in which the counters
are at <ibdev_path>/<port_id>/hw_counters/<file_name>.
In switchdev mode the counters file is located right after the device
name, hence resides at <ibdev_path>/hw_counters.

The fix tries to open the path in the second location after a failure
to open the file from the first location.

Fixes: 9c0a9eed37f1 ("net/mlx5: switch to the names in the shared IB context")
Cc: stable@dpdk.org
Signed-off-by: Shy Shyman <shys@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>

diff --git a/drivers/net/mlx5/linux/mlx5_os.c b/drivers/net/mlx5/linux/mlx5_os.c
index 9622eb3..c4e6c6f 100644 (file)
--- a/drivers/net/mlx5/linux/mlx5_os.c
+++ b/drivers/net/mlx5/linux/mlx5_os.c
@@ -2166,10 +2166,20 @@ mlx5_os_read_dev_stat(struct mlx5_priv *priv, const char *ctr_name,
 
        if (priv->sh) {
                MKSTR(path, "%s/ports/%d/hw_counters/%s",
-                         priv->sh->ibdev_path,
-                         priv->dev_port,
-                         ctr_name);
+                     priv->sh->ibdev_path,
+                     priv->dev_port,
+                     ctr_name);
                fd = open(path, O_RDONLY);
+               /*
+                * in switchdev the file location is not per port
+                * but rather in <ibdev_path>/hw_counters/<file_name>.
+                */
+               if (fd == -1) {
+                       MKSTR(path1, "%s/hw_counters/%s",
+                             priv->sh->ibdev_path,
+                             ctr_name);
+                       fd = open(path1, O_RDONLY);
+               }
                if (fd != -1) {
                        char buf[21] = {'\0'};
                        ssize_t n = read(fd, buf, sizeof(buf));