[PATCH v6 2/5] ethdev: added new function for xstats ID

[Kuba Kozak <kubax.kozak@intel.com>]

Introduced new function: rte_eth_xstats_get_id_by_name
to retrieve xstats ids by its names.

doc: added release note

Signed-off-by: Kuba Kozak <kubax.kozak@intel.com>
---
 doc/guides/rel_notes/release_17_05.rst |  2 ++
 lib/librte_ether/rte_ethdev.c          | 44 ++++++++++++++++++++++++++++++++++
 lib/librte_ether/rte_ethdev.h          | 21 ++++++++++++++++
 lib/librte_ether/rte_ether_version.map |  1 +
 4 files changed, 68 insertions(+)

diff --git a/doc/guides/rel_notes/release_17_05.rst b/doc/guides/rel_notes/release_17_05.rst
index 5b77226..dae4261 100644
--- a/doc/guides/rel_notes/release_17_05.rst
+++ b/doc/guides/rel_notes/release_17_05.rst
@@ -423,6 +423,8 @@ API Changes
   * Added new functions ``rte_eth_xstats_get_all`` and ``rte_eth_xstats_get_names_all to provide backward compatibility for
     ``rte_eth_xstats_get`` and ``rte_eth_xstats_get_names``
 
+  * Added new function ``rte_eth_xstats_get_id_by_name``
+
 ABI Changes
 -----------
 
diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index 0adc1d0..ef30883 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -1476,6 +1476,50 @@ struct rte_eth_dev *
 }
 
 int
+rte_eth_xstats_get_id_by_name(uint8_t port_id, const char *xstat_name,
+		uint64_t *id)
+{
+	int cnt_xstats, idx_xstat;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
+
+	if (!id) {
+		RTE_PMD_DEBUG_TRACE("Error: id pointer is NULL\n");
+		return -1;
+	}
+
+	if (!xstat_name) {
+		RTE_PMD_DEBUG_TRACE("Error: xstat_name pointer is NULL\n");
+		return -1;
+	}
+
+	/* Get count */
+	cnt_xstats = rte_eth_xstats_get_names(port_id, NULL, 0, NULL);
+	if (cnt_xstats  < 0) {
+		RTE_PMD_DEBUG_TRACE("Error: Cannot get count of xstats\n");
+		return -1;
+	}
+
+	/* Get id-name lookup table */
+	struct rte_eth_xstat_name xstats_names[cnt_xstats];
+
+	if (cnt_xstats != rte_eth_xstats_get_names(
+			port_id, xstats_names, cnt_xstats, NULL)) {
+		RTE_PMD_DEBUG_TRACE("Error: Cannot get xstats lookup\n");
+		return -1;
+	}
+
+	for (idx_xstat = 0; idx_xstat < cnt_xstats; idx_xstat++) {
+		if (!strcmp(xstats_names[idx_xstat].name, xstat_name)) {
+			*id = idx_xstat;
+			return 0;
+		};
+	}
+
+	return -EINVAL;
+}
+
+int
 rte_eth_xstats_get_names_v1607(uint8_t port_id,
 	struct rte_eth_xstat_name *xstats_names,
 	unsigned int size)
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index 8c94b88..058c435 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -2346,6 +2346,27 @@ int rte_eth_tx_queue_setup(uint8_t port_id, uint16_t tx_queue_id,
  */
 void rte_eth_stats_reset(uint8_t port_id);
 
+
+/**
+ * Gets the ID of a statistic from its name.
+ *
+ * This function searches for the statistics using string compares, and
+ * as such should not be used on the fast-path. For fast-path retrieval of
+ * specific statistics, store the ID as provided in *id* from this function,
+ * and pass the ID to rte_eth_xstats_get()
+ *
+ * @param port_id The port to look up statistics from
+ * @param xstat_name The name of the statistic to return
+ * @param[out] id A pointer to an app-supplied uint64_t which should be
+ *                set to the ID of the stat if the stat exists.
+ * @return
+ *    0 on success
+ *    -ENODEV for invalid port_id,
+ *    -EINVAL if the xstat_name doesn't exist in port_id
+ */
+int rte_eth_xstats_get_id_by_name(uint8_t port_id, const char *xstat_name,
+		uint64_t *id);
+
 /**
  * Retrieve all extended statistics of an Ethernet device.
  *
diff --git a/lib/librte_ether/rte_ether_version.map b/lib/librte_ether/rte_ether_version.map
index a404434..7c41617 100644
--- a/lib/librte_ether/rte_ether_version.map
+++ b/lib/librte_ether/rte_ether_version.map
@@ -161,6 +161,7 @@ DPDK_17.05 {
 	rte_eth_find_next;
 	rte_eth_xstats_get;
 	rte_eth_xstats_get_all;
+	rte_eth_xstats_get_id_by_name;
 	rte_eth_xstats_get_names;
 	rte_eth_xstats_get_names_all;
 
-- 
1.9.1