From 600ce805363601104cf7678eaf30fa409226996a Mon Sep 17 00:00:00 2001
From: Gaetan Rivet <gaetan.rivet@6wind.com>
Date: Wed, 19 Sep 2018 18:03:35 +0200
Subject: [PATCH] ethdev: add private generic device iterator

This iterator can be customized with a comparison function that will
trigger a stopping condition.

It can be leveraged to write several different iterators that have
similar but non-identical purposes.

It is private to librte_ethdev.

Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
---
 lib/librte_ethdev/Makefile         |  1 +
 lib/librte_ethdev/ethdev_private.c | 31 ++++++++++++++++++++++++++++++
 lib/librte_ethdev/ethdev_private.h | 26 +++++++++++++++++++++++++
 lib/librte_ethdev/meson.build      |  3 ++-
 4 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 lib/librte_ethdev/ethdev_private.c
 create mode 100644 lib/librte_ethdev/ethdev_private.h

diff --git a/lib/librte_ethdev/Makefile b/lib/librte_ethdev/Makefile
index 0935a275e8..4b0eeaac70 100644
--- a/lib/librte_ethdev/Makefile
+++ b/lib/librte_ethdev/Makefile
@@ -18,6 +18,7 @@ EXPORT_MAP := rte_ethdev_version.map
 
 LIBABIVER := 10
 
+SRCS-y += ethdev_private.c
 SRCS-y += rte_ethdev.c
 SRCS-y += rte_flow.c
 SRCS-y += rte_tm.c
diff --git a/lib/librte_ethdev/ethdev_private.c b/lib/librte_ethdev/ethdev_private.c
new file mode 100644
index 0000000000..768c8b2ed5
--- /dev/null
+++ b/lib/librte_ethdev/ethdev_private.c
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2018 Gaëtan Rivet
+ */
+
+#include "rte_ethdev.h"
+#include "ethdev_private.h"
+
+struct rte_eth_dev *
+eth_find_device(const struct rte_eth_dev *start, rte_eth_cmp_t cmp,
+		const void *data)
+{
+	struct rte_eth_dev *edev;
+	ptrdiff_t idx;
+
+	/* Avoid Undefined Behaviour */
+	if (start != NULL &&
+	    (start < &rte_eth_devices[0] ||
+	     start > &rte_eth_devices[RTE_MAX_ETHPORTS]))
+		return NULL;
+	if (start != NULL)
+		idx = start - &rte_eth_devices[0] + 1;
+	else
+		idx = 0;
+	for (; idx < RTE_MAX_ETHPORTS; idx++) {
+		edev = &rte_eth_devices[idx];
+		if (cmp(edev, data) == 0)
+			return edev;
+	}
+	return NULL;
+}
+
diff --git a/lib/librte_ethdev/ethdev_private.h b/lib/librte_ethdev/ethdev_private.h
new file mode 100644
index 0000000000..0f5c6d5c45
--- /dev/null
+++ b/lib/librte_ethdev/ethdev_private.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2018 Gaëtan Rivet
+ */
+
+#ifndef _RTE_ETH_PRIVATE_H_
+#define _RTE_ETH_PRIVATE_H_
+
+#include "rte_ethdev.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Generic rte_eth_dev comparison function. */
+typedef int (*rte_eth_cmp_t)(const struct rte_eth_dev *, const void *);
+
+/* Generic rte_eth_dev iterator. */
+struct rte_eth_dev *
+eth_find_device(const struct rte_eth_dev *_start, rte_eth_cmp_t cmp,
+		const void *data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_ETH_PRIVATE_H_ */
diff --git a/lib/librte_ethdev/meson.build b/lib/librte_ethdev/meson.build
index 596cd0f39a..7798217d04 100644
--- a/lib/librte_ethdev/meson.build
+++ b/lib/librte_ethdev/meson.build
@@ -4,7 +4,8 @@
 name = 'ethdev'
 version = 10
 allow_experimental_apis = true
-sources = files('ethdev_profile.c',
+sources = files('ethdev_private.c',
+	'ethdev_profile.c',
 	'rte_ethdev.c',
 	'rte_flow.c',
 	'rte_mtr.c',
-- 
2.20.1