[dpdk-dev] [PATCH 07/11] vdev: allow external registration of virtual device drivers

[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 change:
- we don't need to reference pmd_ring, pmd_pcap and pmd_xenvirt in EAL code
- it is now possible to provide 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/eal_common_vdev.c  | 72 +++++++++++++++-----------------
 lib/librte_eal/linuxapp/eal/eal.c        |  7 ++--
 lib/librte_pmd_pcap/rte_eth_pcap.c       | 16 ++++++-
 lib/librte_pmd_pcap/rte_eth_pcap.h       |  8 ----
 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 | 14 ++++++-
 lib/librte_pmd_xenvirt/rte_eth_xenvirt.h |  4 +-
 9 files changed, 85 insertions(+), 63 deletions(-)

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/eal_common_vdev.c b/lib/librte_eal/common/eal_common_vdev.c
index 02d3fd6..84547c7 100644
--- a/lib/librte_eal/common/eal_common_vdev.c
+++ b/lib/librte_eal/common/eal_common_vdev.c
@@ -34,7 +34,11 @@
 
 #include <string.h>
 #include <inttypes.h>
-#include <rte_string_fns.h>
+#include <sys/queue.h>
+
+#include <rte_vdev.h>
+#include <rte_devargs.h>
+#include <rte_debug.h>
 #ifdef RTE_LIBRTE_PMD_RING
 #include <rte_eth_ring.h>
 #endif
@@ -46,44 +50,37 @@
 #endif
 #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 +88,17 @@ 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/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 2f3222d..6502755 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -1039,10 +1039,8 @@ rte_eal_init(int argc, char **argv)
 
 	rte_eal_mcfg_complete();
 
-	if (rte_eal_vdev_init() < 0)
-		rte_panic("Cannot init virtual devices\n");
-
 	TAILQ_FOREACH(solib, &solib_list, next) {
+		RTE_LOG(INFO, EAL, "open shared lib %s\n", solib->name);
 		solib->lib_handle = dlopen(solib->name, RTLD_NOW);
 		if ((solib->lib_handle == NULL) && (solib->name[0] != '/')) {
 			/* relative path: try again with "./" prefix */
@@ -1054,6 +1052,9 @@ rte_eal_init(int argc, char **argv)
 			RTE_LOG(WARNING, EAL, "%s\n", dlerror());
 	}
 
+	if (rte_eal_vdev_init() < 0)
+		rte_panic("Cannot init virtual devices\n");
+
 	RTE_LOG(DEBUG, EAL, "Master core %u is ready (tid=%x)\n",
 		rte_config.master_lcore, (int)thread_id);
 
diff --git a/lib/librte_pmd_pcap/rte_eth_pcap.c b/lib/librte_pmd_pcap/rte_eth_pcap.c
index 03e6e6c..15f7469 100644
--- a/lib/librte_pmd_pcap/rte_eth_pcap.c
+++ b/lib/librte_pmd_pcap/rte_eth_pcap.c
@@ -40,6 +40,7 @@
 #include <rte_string_fns.h>
 #include <rte_cycles.h>
 #include <rte_kvargs.h>
+#include <rte_vdev.h>
 
 #include <net/if.h>
 
@@ -697,8 +698,8 @@ 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;
@@ -777,3 +778,14 @@ 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
index c0bc5d8..473b6cb 100644
--- a/lib/librte_pmd_pcap/rte_eth_pcap.h
+++ b/lib/librte_pmd_pcap/rte_eth_pcap.h
@@ -45,8 +45,6 @@ extern "C" {
 #undef PCAP_CAN_SEND
 #endif
 
-#define RTE_ETH_PCAP_PARAM_NAME "eth_pcap"
-
 /* struct args_dict is declared in rte_eth_pcap_args_parser.h */
 struct args_dict;
 
@@ -64,12 +62,6 @@ int rte_eth_from_pcaps_n_dumpers(pcap_t * const rx_queues[],
 		const unsigned numa_node,
 		struct args_dict *dict);
 
-/**
- * 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
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..d142973 100644
--- a/lib/librte_pmd_xenvirt/rte_eth_xenvirt.c
+++ b/lib/librte_pmd_xenvirt/rte_eth_xenvirt.c
@@ -689,7 +689,7 @@ err:
 
 /*TODO: Support multiple process model */
 int
-rte_pmd_xenvirt_init(const char *name, const char *params)
+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..f3f3220 100644
--- a/lib/librte_pmd_xenvirt/rte_eth_xenvirt.h
+++ b/lib/librte_pmd_xenvirt/rte_eth_xenvirt.h
@@ -41,13 +41,11 @@ 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);
+int rte_pmd_xenvirt_devinit(const char *name, const char *params);
 
 /**
  * Creates mempool for xen virtio PMD.
-- 
1.8.5.3