[dpdk-dev] [PATCH v2 07/11 1/2] vdev: new registration API

[Olivier Matz <olivier.matz@6wind.com>]

Instead of having a list of virtual device drivers in EAL code, add an
API to register drivers. Thanks to this new registration method, we can
remove the references to pmd_ring, pmd_pcap and pmd_xenvirt in EAL code.
This also enables the ability to register a virtual device driver as
a shared library.

The registration is done in an init function flaged with
__attribute__((constructor)). The new convention is to name this
function rte_pmd_xyz_init(). The per-device init function is renamed
rte_pmd_xyz_devinit().

By the way the internal PMDs are now also .so/standalone ready. Let's do
it later on. It will be required to ease maintenance.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 app/test/test_pmd_ring.c                 |  6 +--
 lib/librte_eal/common/Makefile           |  2 +-
 lib/librte_eal/common/eal_common_vdev.c  | 80 ++++++++++++----------------
 lib/librte_eal/common/include/rte_vdev.h | 90 ++++++++++++++++++++++++++++++++
 lib/librte_pmd_pcap/Makefile             |  2 +-
 lib/librte_pmd_pcap/rte_eth_pcap.c       | 18 +++++--
 lib/librte_pmd_pcap/rte_eth_pcap.h       | 54 -------------------
 lib/librte_pmd_ring/rte_eth_ring.c       | 15 +++++-
 lib/librte_pmd_ring/rte_eth_ring.h       |  6 +--
 lib/librte_pmd_xenvirt/rte_eth_xenvirt.c | 16 +++++-
 lib/librte_pmd_xenvirt/rte_eth_xenvirt.h |  8 ---
 11 files changed, 173 insertions(+), 124 deletions(-)
 create mode 100644 lib/librte_eal/common/include/rte_vdev.h
 delete mode 100644 lib/librte_pmd_pcap/rte_eth_pcap.h

Hi Thomas,

You are right, I splitted the previous commit as requested. I also
completely remove rte_eth_pcap.h which is not used anymore.

diff --git a/app/test/test_pmd_ring.c b/app/test/test_pmd_ring.c
index c8242b3..4d9c2ba 100644
--- a/app/test/test_pmd_ring.c
+++ b/app/test/test_pmd_ring.c
@@ -315,12 +315,12 @@ test_pmd_ring_init(void)
 
 	printf("Testing ring pmd init\n");
 
-	if (rte_pmd_ring_init(name1, params_null) < 0) {
+	if (rte_pmd_ring_devinit(name1, params_null) < 0) {
 		printf("Testing ring pmd init fail\n");
 		return -1;
 	}
 
-	if (rte_pmd_ring_init(name2, params) < 0) {
+	if (rte_pmd_ring_devinit(name2, params) < 0) {
 		printf("Testing ring pmd init fail\n");
 		return -1;
 	}
@@ -372,7 +372,7 @@ test_pmd_ring_init(void)
 	rte_eth_dev_stop(RXTX_PORT2);
 
 	/* Test init same name pmd ring */
-	rte_pmd_ring_init(name1, params_null);
+	rte_pmd_ring_devinit(name1, params_null);
 	return 0;
 }
 
diff --git a/lib/librte_eal/common/Makefile b/lib/librte_eal/common/Makefile
index b9f3b88..2f99bf4 100644
--- a/lib/librte_eal/common/Makefile
+++ b/lib/librte_eal/common/Makefile
@@ -38,7 +38,7 @@ INC += rte_pci_dev_ids.h rte_per_lcore.h rte_prefetch.h rte_random.h
 INC += rte_rwlock.h rte_spinlock.h rte_tailq.h rte_interrupts.h rte_alarm.h
 INC += rte_string_fns.h rte_cpuflags.h rte_version.h rte_tailq_elem.h
 INC += rte_eal_memconfig.h rte_malloc_heap.h
-INC += rte_hexdump.h rte_devargs.h
+INC += rte_hexdump.h rte_devargs.h rte_vdev.h
 
 ifeq ($(CONFIG_RTE_INSECURE_FUNCTION_WARNING),y)
 INC += rte_warnings.h
diff --git a/lib/librte_eal/common/eal_common_vdev.c b/lib/librte_eal/common/eal_common_vdev.c
index 02d3fd6..62d0302 100644
--- a/lib/librte_eal/common/eal_common_vdev.c
+++ b/lib/librte_eal/common/eal_common_vdev.c
@@ -34,56 +34,43 @@
 
 #include <string.h>
 #include <inttypes.h>
-#include <rte_string_fns.h>
-#ifdef RTE_LIBRTE_PMD_RING
-#include <rte_eth_ring.h>
-#endif
-#ifdef RTE_LIBRTE_PMD_PCAP
-#include <rte_eth_pcap.h>
-#endif
-#ifdef RTE_LIBRTE_PMD_XENVIRT
-#include <rte_eth_xenvirt.h>
-#endif
+#include <sys/queue.h>
+
+#include <rte_vdev.h>
+#include <rte_devargs.h>
 #include <rte_debug.h>
 #include <rte_devargs.h>
+
 #include "eal_private.h"
 
-struct device_init {
-	const char *dev_prefix;
-	int (*init_fn)(const char*, const char *);
-};
+/** Global list of virtual device drivers. */
+static struct rte_vdev_driver_list vdev_driver_list =
+	TAILQ_HEAD_INITIALIZER(vdev_driver_list);
 
-#define NUM_DEV_TYPES (sizeof(dev_types)/sizeof(dev_types[0]))
-struct device_init dev_types[] = {
-#ifdef RTE_LIBRTE_PMD_RING
-		{
-			.dev_prefix = RTE_ETH_RING_PARAM_NAME,
-			.init_fn = rte_pmd_ring_init
-		},
-#endif
-#ifdef RTE_LIBRTE_PMD_PCAP
-		{
-			.dev_prefix = RTE_ETH_PCAP_PARAM_NAME,
-			.init_fn = rte_pmd_pcap_init
-		},
-#endif
-#ifdef RTE_LIBRTE_PMD_XENVIRT
-		{
-			.dev_prefix = RTE_ETH_XENVIRT_PARAM_NAME,
-			.init_fn = rte_pmd_xenvirt_init
-		},
-#endif
-		{
-			.dev_prefix = "-nodev-",
-			.init_fn = NULL
-		}
-};
+/* register a driver */
+void
+rte_eal_vdev_driver_register(struct rte_vdev_driver *driver)
+{
+	TAILQ_INSERT_TAIL(&vdev_driver_list, driver, next);
+}
+
+/* unregister a driver */
+void
+rte_eal_vdev_driver_unregister(struct rte_vdev_driver *driver)
+{
+	TAILQ_REMOVE(&vdev_driver_list, driver, next);
+}
 
 int
 rte_eal_vdev_init(void)
 {
 	struct rte_devargs *devargs;
-	uint8_t i;
+	struct rte_vdev_driver *driver;
+
+	/* No need to register drivers that are embeded in DPDK
+	 * (pmd_pcap, pmd_ring, ...). The initialization function have
+	 * the ((constructor)) attribute so they will register at
+	 * startup. */
 
 	/* call the init function for each virtual device */
 	TAILQ_FOREACH(devargs, &devargs_list, next) {
@@ -91,18 +78,17 @@ rte_eal_vdev_init(void)
 		if (devargs->type != RTE_DEVTYPE_VIRTUAL)
 			continue;
 
-		for (i = 0; i < NUM_DEV_TYPES; i++) {
+		TAILQ_FOREACH(driver, &vdev_driver_list, next) {
 			/* search a driver prefix in virtual device name */
-			if (!strncmp(dev_types[i].dev_prefix,
-				    devargs->virtual.drv_name,
-				     sizeof(dev_types[i].dev_prefix) - 1)) {
-				dev_types[i].init_fn(devargs->virtual.drv_name,
-						     devargs->args);
+			if (!strncmp(driver->name, devargs->virtual.drv_name,
+					strlen(driver->name))) {
+				driver->init(devargs->virtual.drv_name,
+					devargs->args);
 				break;
 			}
 		}
 
-		if (i == NUM_DEV_TYPES) {
+		if (driver == NULL) {
 			rte_panic("no driver found for %s\n",
 				  devargs->virtual.drv_name);
 		}
diff --git a/lib/librte_eal/common/include/rte_vdev.h b/lib/librte_eal/common/include/rte_vdev.h
new file mode 100644
index 0000000..48f71b7
--- /dev/null
+++ b/lib/librte_eal/common/include/rte_vdev.h
@@ -0,0 +1,90 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2014 6WIND S.A.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of 6WIND S.A. nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _RTE_VDEV_H_
+#define _RTE_VDEV_H_
+
+/**
+ * @file
+ *
+ * RTE Virtual Devices Interface
+ *
+ * This file manages the list of the virtual device drivers.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <sys/queue.h>
+
+/** Double linked list of virtual device drivers. */
+TAILQ_HEAD(rte_vdev_driver_list, rte_vdev_driver);
+
+/**
+ * Initialization function called for each virtual device probing.
+ */
+typedef int (rte_vdev_init_t)(const char *name, const char *args);
+
+/**
+ * A structure describing a virtual device driver.
+ */
+struct rte_vdev_driver {
+	TAILQ_ENTRY(rte_vdev_driver) next;  /**< Next in list. */
+	const char *name;                   /**< Driver name. */
+	rte_vdev_init_t *init;              /**< Device init. function. */
+};
+
+/**
+ * Register a virtual device driver.
+ *
+ * @param driver
+ *   A pointer to a rte_vdev structure describing the driver
+ *   to be registered.
+ */
+void rte_eal_vdev_driver_register(struct rte_vdev_driver *driver);
+
+/**
+ * Unregister a virtual device driver.
+ *
+ * @param driver
+ *   A pointer to a rte_vdev structure describing the driver
+ *   to be unregistered.
+ */
+void rte_eal_vdev_driver_unregister(struct rte_vdev_driver *driver);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_VDEV_H_ */
diff --git a/lib/librte_pmd_pcap/Makefile b/lib/librte_pmd_pcap/Makefile
index 5218f28..a8b289f 100644
--- a/lib/librte_pmd_pcap/Makefile
+++ b/lib/librte_pmd_pcap/Makefile
@@ -48,7 +48,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_PMD_PCAP) += rte_eth_pcap.c
 #
 # Export include files
 #
-SYMLINK-y-include += rte_eth_pcap.h
+SYMLINK-y-include +=
 
 # this lib depends upon:
 DEPDIRS-$(CONFIG_RTE_LIBRTE_PMD_PCAP) += lib/librte_mbuf
diff --git a/lib/librte_pmd_pcap/rte_eth_pcap.c b/lib/librte_pmd_pcap/rte_eth_pcap.c
index fe94a79..680dfdc 100644
--- a/lib/librte_pmd_pcap/rte_eth_pcap.c
+++ b/lib/librte_pmd_pcap/rte_eth_pcap.c
@@ -40,10 +40,11 @@
 #include <rte_string_fns.h>
 #include <rte_cycles.h>
 #include <rte_kvargs.h>
+#include <rte_vdev.h>
 
 #include <net/if.h>
 
-#include "rte_eth_pcap.h"
+#include <pcap.h>
 
 #define RTE_ETH_PCAP_SNAPSHOT_LEN 65535
 #define RTE_ETH_PCAP_SNAPLEN 4096
@@ -685,8 +686,8 @@ rte_eth_from_pcaps(pcap_t * const rx_queues[],
 }
 
 
-int
-rte_pmd_pcap_init(const char *name, const char *params)
+static int
+rte_pmd_pcap_devinit(const char *name, const char *params)
 {
 	unsigned numa_node, using_dumpers = 0;
 	int ret;
@@ -766,3 +767,14 @@ rte_pmd_pcap_init(const char *name, const char *params)
 
 }
 
+static struct rte_vdev_driver pmd_pcap_drv = {
+	.name = "eth_pcap",
+	.init = rte_pmd_pcap_devinit,
+};
+
+__attribute__((constructor))
+static void
+rte_pmd_pcap_init(void)
+{
+	rte_eal_vdev_driver_register(&pmd_pcap_drv);
+}
diff --git a/lib/librte_pmd_pcap/rte_eth_pcap.h b/lib/librte_pmd_pcap/rte_eth_pcap.h
deleted file mode 100644
index 79373c0..0000000
--- a/lib/librte_pmd_pcap/rte_eth_pcap.h
+++ /dev/null
@@ -1,54 +0,0 @@
-/*-
- *   BSD LICENSE
- * 
- *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
- *   All rights reserved.
- * 
- *   Redistribution and use in source and binary forms, with or without
- *   modification, are permitted provided that the following conditions
- *   are met:
- * 
- *     * Redistributions of source code must retain the above copyright
- *       notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above copyright
- *       notice, this list of conditions and the following disclaimer in
- *       the documentation and/or other materials provided with the
- *       distribution.
- *     * Neither the name of Intel Corporation nor the names of its
- *       contributors may be used to endorse or promote products derived
- *       from this software without specific prior written permission.
- * 
- *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifndef _RTE_ETH_PCAP_H_
-#define _RTE_ETH_PCAP_H_
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-#include <pcap.h>
-
-#define RTE_ETH_PCAP_PARAM_NAME "eth_pcap"
-
-/**
- * For use by the EAL only. Called as part of EAL init to set up any dummy NICs
- * configured on command line.
- */
-int rte_pmd_pcap_init(const char *name, const char *params);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif
diff --git a/lib/librte_pmd_ring/rte_eth_ring.c b/lib/librte_pmd_ring/rte_eth_ring.c
index 24635f3..cee3fff 100644
--- a/lib/librte_pmd_ring/rte_eth_ring.c
+++ b/lib/librte_pmd_ring/rte_eth_ring.c
@@ -37,6 +37,7 @@
 #include <rte_malloc.h>
 #include <rte_memcpy.h>
 #include <rte_string_fns.h>
+#include <rte_vdev.h>
 
 struct ring_queue {
 	struct rte_ring *rng;
@@ -382,7 +383,7 @@ rte_eth_ring_pair_attach(const char *name, const unsigned numa_node)
 }
 
 int
-rte_pmd_ring_init(const char *name, const char *params)
+rte_pmd_ring_devinit(const char *name, const char *params)
 {
 	RTE_LOG(INFO, PMD, "Initializing pmd_ring for %s\n", name);
 
@@ -395,3 +396,15 @@ rte_pmd_ring_init(const char *name, const char *params)
 	}
 	return 0;
 }
+
+static struct rte_vdev_driver pmd_ring_drv = {
+	.name = "eth_ring",
+	.init = rte_pmd_ring_devinit,
+};
+
+__attribute__((constructor))
+static void
+rte_pmd_ring_init(void)
+{
+	rte_eal_vdev_driver_register(&pmd_ring_drv);
+}
diff --git a/lib/librte_pmd_ring/rte_eth_ring.h b/lib/librte_pmd_ring/rte_eth_ring.h
index a222ecb..b84a29e 100644
--- a/lib/librte_pmd_ring/rte_eth_ring.h
+++ b/lib/librte_pmd_ring/rte_eth_ring.h
@@ -40,8 +40,6 @@ extern "C" {
 
 #include <rte_ring.h>
 
-#define RTE_ETH_RING_PARAM_NAME "eth_ring"
-
 int rte_eth_from_rings(struct rte_ring * const rx_queues[],
 		const unsigned nb_rx_queues,
 		struct rte_ring *const tx_queues[],
@@ -52,10 +50,10 @@ int rte_eth_ring_pair_create(const char *name, const unsigned numa_node);
 int rte_eth_ring_pair_attach(const char *name, const unsigned numa_node);
 
 /**
- * For use by the EAL only. Called as part of EAL init to set up any dummy NICs
+ * For use by test apps only. Called as part of EAL init to set up any dummy NICs
  * configured on command line.
  */
-int rte_pmd_ring_init(const char *name, const char *params);
+int rte_pmd_ring_devinit(const char *name, const char *params);
 
 #ifdef __cplusplus
 }
diff --git a/lib/librte_pmd_xenvirt/rte_eth_xenvirt.c b/lib/librte_pmd_xenvirt/rte_eth_xenvirt.c
index bad8dd4..533aa76 100644
--- a/lib/librte_pmd_xenvirt/rte_eth_xenvirt.c
+++ b/lib/librte_pmd_xenvirt/rte_eth_xenvirt.c
@@ -688,8 +688,8 @@ err:
 
 
 /*TODO: Support multiple process model */
-int
-rte_pmd_xenvirt_init(const char *name, const char *params)
+static int
+rte_pmd_xenvirt_devinit(const char *name, const char *params)
 {
 	if (virtio_idx == 0) {
 		if (xenstore_init() != 0) {
@@ -704,3 +704,15 @@ rte_pmd_xenvirt_init(const char *name, const char *params)
 	eth_dev_xenvirt_create(name, params, rte_socket_id(), DEV_CREATE);
 	return 0;
 }
+
+static struct rte_vdev_driver pmd_xenvirt_drv = {
+	.name = "eth_xenvirt",
+	.init = rte_pmd_xenvirt_devinit,
+};
+
+__attribute__((constructor))
+static void
+rte_pmd_xenvirt_init(void)
+{
+	rte_eal_vdev_driver_register(&pmd_xenvirt_drv);
+}
diff --git a/lib/librte_pmd_xenvirt/rte_eth_xenvirt.h b/lib/librte_pmd_xenvirt/rte_eth_xenvirt.h
index cb1924a..acdeb30 100644
--- a/lib/librte_pmd_xenvirt/rte_eth_xenvirt.h
+++ b/lib/librte_pmd_xenvirt/rte_eth_xenvirt.h
@@ -41,14 +41,6 @@ extern "C" {
 #include <rte_mempool.h>
 #include <rte_ring.h>
 
-#define RTE_ETH_XENVIRT_PARAM_NAME "eth_xenvirt"
-
-/**
- * For use by the EAL only. Called as part of EAL init to set up any dummy NICs
- * configured on command line.
- */
-int rte_pmd_xenvirt_init(const char *name, const char *params);
-
 /**
  * Creates mempool for xen virtio PMD.
  * This function uses memzone_reserve to allocate memory for meta data,
-- 
1.8.5.3