[dpdk-dev] [PATCH v2 2/5] devargs: refactor scratch buffer storage

[Xueming Li <xuemingl@nvidia.com>]

In current design, legacy parser rte_devargs_parse() saved scratch
buffer to devargs.args while new parser rte_devargs_layers_parse() saved
to devargs.data. Code using devargs had to know the difference and
cleaned up memory accordingly - error prone.

This patch unifies data the dedicate scratch buffer, introduces
rte_devargs_free() function to wrap the memory memory clean up.

Signed-off-by: Xueming Li <xuemingl@nvidia.com>
---
 app/test-pmd/config.c                        |  7 ++--
 app/test-pmd/testpmd.c                       |  5 ++-
 drivers/bus/vdev/vdev.c                      |  9 ++--
 drivers/net/failsafe/failsafe_args.c         |  3 +-
 drivers/net/failsafe/failsafe_eal.c          |  2 +-
 examples/multi_process/hotplug_mp/commands.c |  6 +--
 lib/librte_eal/common/eal_common_dev.c       |  9 ++--
 lib/librte_eal/common/eal_common_devargs.c   | 43 +++++++++++---------
 lib/librte_eal/common/hotplug_mp.c           |  6 +--
 lib/librte_eal/include/rte_devargs.h         | 18 ++++++--
 lib/librte_eal/rte_eal_exports.def           |  1 +
 lib/librte_eal/version.map                   |  1 +
 lib/librte_ethdev/rte_ethdev.c               |  7 ++--
 13 files changed, 64 insertions(+), 53 deletions(-)

diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
index 3f6c8642b1..21bdece399 100644
--- a/app/test-pmd/config.c
+++ b/app/test-pmd/config.c
@@ -509,8 +509,6 @@ device_infos_display(const char *identifier)
 
 	if (rte_devargs_parsef(&da, "%s", identifier)) {
 		printf("cannot parse identifier\n");
-		if (da.args)
-			free(da.args);
 		return;
 	}
 
@@ -558,6 +556,7 @@ device_infos_display(const char *identifier)
 			}
 		}
 	};
+	rte_devargs_free(&da);
 }
 
 void
@@ -602,8 +601,8 @@ port_infos_display(portid_t port_id)
 	else
 		printf("\nFirmware-version: %s", "not available");
 
-	if (dev_info.device->devargs && dev_info.device->devargs->args)
-		printf("\nDevargs: %s", dev_info.device->devargs->args);
+	if (dev_info.device->devargs && dev_info.device->devargs->src)
+		printf("\nDevargs: %s", dev_info.device->devargs->src);
 	printf("\nConnect to socket: %u", port->socket_id);
 
 	if (port_numa[port_id] != NUMA_NO_CONFIG) {
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 2b60f6c5d3..ea27779bfd 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -2987,8 +2987,6 @@ detach_devargs(char *identifier)
 	memset(&da, 0, sizeof(da));
 	if (rte_devargs_parsef(&da, "%s", identifier)) {
 		printf("cannot parse identifier\n");
-		if (da.args)
-			free(da.args);
 		return;
 	}
 
@@ -2997,6 +2995,7 @@ detach_devargs(char *identifier)
 			if (ports[port_id].port_status != RTE_PORT_STOPPED) {
 				printf("Port %u not stopped\n", port_id);
 				rte_eth_iterator_cleanup(&iterator);
+				rte_devargs_free(&da);
 				return;
 			}
 			port_flow_flush(port_id);
@@ -3006,6 +3005,7 @@ detach_devargs(char *identifier)
 	if (rte_eal_hotplug_remove(da.bus->name, da.name) != 0) {
 		TESTPMD_LOG(ERR, "Failed to detach device %s(%s)\n",
 			    da.name, da.bus->name);
+		rte_devargs_free(&da);
 		return;
 	}
 
@@ -3014,6 +3014,7 @@ detach_devargs(char *identifier)
 	printf("Device %s is detached\n", identifier);
 	printf("Now total ports is %d\n", nb_ports);
 	printf("Done\n");
+	rte_devargs_free(&da);
 }
 
 void
diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c
index acfd78828f..012326d809 100644
--- a/drivers/bus/vdev/vdev.c
+++ b/drivers/bus/vdev/vdev.c
@@ -236,13 +236,14 @@ alloc_devargs(const char *name, const char *args)
 
 	devargs->bus = &rte_vdev_bus;
 	if (args)
-		devargs->args = strdup(args);
+		devargs->data = strdup(args);
 	else
-		devargs->args = strdup("");
+		devargs->data = strdup("");
+	devargs->args = devargs->data;
 
 	ret = strlcpy(devargs->name, name, sizeof(devargs->name));
 	if (ret < 0 || ret >= (int)sizeof(devargs->name)) {
-		free(devargs->args);
+		rte_devargs_free(devargs);
 		free(devargs);
 		return NULL;
 	}
@@ -296,7 +297,7 @@ insert_vdev(const char *name, const char *args,
 
 	return 0;
 fail:
-	free(devargs->args);
+	rte_devargs_free(devargs);
 	free(devargs);
 	free(dev);
 	return ret;
diff --git a/drivers/net/failsafe/failsafe_args.c b/drivers/net/failsafe/failsafe_args.c
index 707490b94c..52fdcb977f 100644
--- a/drivers/net/failsafe/failsafe_args.c
+++ b/drivers/net/failsafe/failsafe_args.c
@@ -451,8 +451,7 @@ failsafe_args_free(struct rte_eth_dev *dev)
 		sdev->cmdline = NULL;
 		free(sdev->fd_str);
 		sdev->fd_str = NULL;
-		free(sdev->devargs.args);
-		sdev->devargs.args = NULL;
+		rte_devargs_free(&sdev->devargs);
 	}
 }
 
diff --git a/drivers/net/failsafe/failsafe_eal.c b/drivers/net/failsafe/failsafe_eal.c
index b9fc508673..3a4d8c835a 100644
--- a/drivers/net/failsafe/failsafe_eal.c
+++ b/drivers/net/failsafe/failsafe_eal.c
@@ -79,7 +79,7 @@ fs_bus_init(struct rte_eth_dev *dev)
 					rte_eth_devices[pid].device->devargs;
 
 			/* Take control of probed device. */
-			free(da->args);
+			rte_devargs_free(da);
 			memset(da, 0, sizeof(*da));
 			if (probed_da != NULL)
 				snprintf(devstr, sizeof(devstr), "%s,%s",
diff --git a/examples/multi_process/hotplug_mp/commands.c b/examples/multi_process/hotplug_mp/commands.c
index a8a39d07f7..e593cad56c 100644
--- a/examples/multi_process/hotplug_mp/commands.c
+++ b/examples/multi_process/hotplug_mp/commands.c
@@ -121,8 +121,6 @@ static void cmd_dev_attach_parsed(void *parsed_result,
 
 	if (rte_devargs_parsef(&da, "%s", res->devargs)) {
 		cmdline_printf(cl, "cannot parse devargs\n");
-		if (da.args)
-			free(da.args);
 		return;
 	}
 
@@ -131,6 +129,7 @@ static void cmd_dev_attach_parsed(void *parsed_result,
 	else
 		cmdline_printf(cl, "failed to attached device %s\n",
 				da.name);
+	rte_devargs_free(&da);
 }
 
 cmdline_parse_token_string_t cmd_dev_attach_attach =
@@ -168,8 +167,6 @@ static void cmd_dev_detach_parsed(void *parsed_result,
 
 	if (rte_devargs_parsef(&da, "%s", res->devargs)) {
 		cmdline_printf(cl, "cannot parse devargs\n");
-		if (da.args)
-			free(da.args);
 		return;
 	}
 
@@ -180,6 +177,7 @@ static void cmd_dev_detach_parsed(void *parsed_result,
 	else
 		cmdline_printf(cl, "failed to dettach device %s\n",
 			da.name);
+	rte_devargs_free(&da);
 }
 
 cmdline_parse_token_string_t cmd_dev_detach_detach =
diff --git a/lib/librte_eal/common/eal_common_dev.c b/lib/librte_eal/common/eal_common_dev.c
index 8a3bd3100a..4b4d589f64 100644
--- a/lib/librte_eal/common/eal_common_dev.c
+++ b/lib/librte_eal/common/eal_common_dev.c
@@ -185,10 +185,8 @@ local_dev_probe(const char *devargs, struct rte_device **new_dev)
 	return ret;
 
 err_devarg:
-	if (rte_devargs_remove(da) != 0) {
-		free(da->args);
-		free(da);
-	}
+	if (rte_devargs_remove(da) != 0)
+		rte_devargs_free(da);
 	return ret;
 }
 
@@ -586,7 +584,7 @@ rte_dev_iterator_init(struct rte_dev_iterator *it,
 	it->bus_str = NULL;
 	it->cls_str = NULL;
 
-	devargs.data = dev_str;
+	devargs.data = (void *)(intptr_t)dev_str;
 	if (rte_devargs_layers_parse(&devargs, dev_str))
 		goto get_out;
 
@@ -619,6 +617,7 @@ rte_dev_iterator_init(struct rte_dev_iterator *it,
 	it->device = NULL;
 	it->class_device = NULL;
 get_out:
+	rte_devargs_free(&devargs);
 	return -rte_errno;
 }
 
diff --git a/lib/librte_eal/common/eal_common_devargs.c b/lib/librte_eal/common/eal_common_devargs.c
index c3969ff158..9c7a7de30e 100644
--- a/lib/librte_eal/common/eal_common_devargs.c
+++ b/lib/librte_eal/common/eal_common_devargs.c
@@ -144,13 +144,14 @@ rte_devargs_layers_parse(struct rte_devargs *devargs,
 	devargs->drv_str = layers[2].str;
 	devargs->bus = bus;
 	devargs->cls = cls;
+	devargs->src = devstr;
 
 	/* If we own the data, clean up a bit
 	 * the several layers string, to ease
 	 * their parsing afterward.
 	 */
 	if (devargs->data != devstr) {
-		char *s = (void *)(intptr_t)(devargs->data);
+		char *s = devargs->data;
 
 		while ((s = strchr(s, '/'))) {
 			*s = '\0';
@@ -164,12 +165,8 @@ rte_devargs_layers_parse(struct rte_devargs *devargs,
 			rte_kvargs_free(layers[i].kvlist);
 	}
 	if (ret != 0) {
-		if (devargs->data && devargs->data != devstr) {
-			/* Free duplicated data. */
-			free(devargs->data);
-			devargs->data = NULL;
-		}
 		rte_errno = -ret;
+		rte_devargs_free(devargs);
 	}
 	return ret;
 }
@@ -225,13 +222,17 @@ rte_devargs_parse(struct rte_devargs *da, const char *dev)
 	da->bus = bus;
 	/* Parse eventual device arguments */
 	if (devname[i] == ',')
-		da->args = strdup(&devname[i + 1]);
+		da->data = strdup(&devname[i + 1]);
 	else
-		da->args = strdup("");
-	if (da->args == NULL) {
+		da->data = strdup("");
+	if (da->data == NULL) {
 		RTE_LOG(ERR, EAL, "not enough memory to parse arguments\n");
 		return -ENOMEM;
 	}
+	da->drv_str = da->data;
+
+	da->src = dev;
+
 	return 0;
 }
 
@@ -266,6 +267,15 @@ rte_devargs_parsef(struct rte_devargs *da, const char *format, ...)
 	return ret;
 }
 
+void
+rte_devargs_free(struct rte_devargs *da)
+{
+	if (da && da->data && da->data != da->src)
+		free(da->data);
+	da->data = NULL;
+	da->src = NULL;
+}
+
 int
 rte_devargs_insert(struct rte_devargs **da)
 {
@@ -282,15 +292,8 @@ rte_devargs_insert(struct rte_devargs **da)
 		if (strcmp(listed_da->bus->name, (*da)->bus->name) == 0 &&
 				strcmp(listed_da->name, (*da)->name) == 0) {
 			/* device already in devargs list, must be updated */
-			listed_da->type = (*da)->type;
-			listed_da->policy = (*da)->policy;
-			free(listed_da->args);
-			listed_da->args = (*da)->args;
-			listed_da->bus = (*da)->bus;
-			listed_da->cls = (*da)->cls;
-			listed_da->bus_str = (*da)->bus_str;
-			listed_da->cls_str = (*da)->cls_str;
-			listed_da->data = (*da)->data;
+			rte_devargs_free(listed_da);
+			*listed_da = **da;
 			/* replace provided devargs with found one */
 			free(*da);
 			*da = listed_da;
@@ -332,7 +335,7 @@ rte_devargs_add(enum rte_devtype devtype, const char *devargs_str)
 
 fail:
 	if (devargs) {
-		free(devargs->args);
+		rte_devargs_free(devargs);
 		free(devargs);
 	}
 
@@ -352,7 +355,7 @@ rte_devargs_remove(struct rte_devargs *devargs)
 		if (strcmp(d->bus->name, devargs->bus->name) == 0 &&
 		    strcmp(d->name, devargs->name) == 0) {
 			TAILQ_REMOVE(&devargs_list, d, next);
-			free(d->args);
+			rte_devargs_free(d);
 			free(d);
 			return 0;
 		}
diff --git a/lib/librte_eal/common/hotplug_mp.c b/lib/librte_eal/common/hotplug_mp.c
index ee791903b3..13f2a427cf 100644
--- a/lib/librte_eal/common/hotplug_mp.c
+++ b/lib/librte_eal/common/hotplug_mp.c
@@ -95,6 +95,7 @@ __handle_secondary_request(void *param)
 
 	tmp_req = *req;
 
+	memset(&da, 0, sizeof(da));
 	if (req->t == EAL_DEV_REQ_TYPE_ATTACH) {
 		ret = local_dev_probe(req->devargs, &dev);
 		if (ret != 0) {
@@ -118,8 +119,6 @@ __handle_secondary_request(void *param)
 		ret = rte_devargs_parse(&da, req->devargs);
 		if (ret != 0)
 			goto finish;
-		free(da.args); /* we don't need those */
-		da.args = NULL;
 
 		ret = eal_dev_hotplug_request_to_secondary(&tmp_req);
 		if (ret != 0) {
@@ -176,6 +175,7 @@ __handle_secondary_request(void *param)
 	if (ret)
 		RTE_LOG(ERR, EAL, "failed to send response to secondary\n");
 
+	rte_devargs_free(&da);
 	free(bundle->peer);
 	free(bundle);
 }
@@ -283,7 +283,7 @@ static void __handle_primary_request(void *param)
 
 		ret = local_dev_remove(dev);
 quit:
-		free(da->args);
+		rte_devargs_free(da);
 		free(da);
 		break;
 	default:
diff --git a/lib/librte_eal/include/rte_devargs.h b/lib/librte_eal/include/rte_devargs.h
index 296f19324f..4a917a266b 100644
--- a/lib/librte_eal/include/rte_devargs.h
+++ b/lib/librte_eal/include/rte_devargs.h
@@ -60,16 +60,16 @@ struct rte_devargs {
 	/** Name of the device. */
 	char name[RTE_DEV_NAME_MAX_LEN];
 	RTE_STD_C11
-	union {
-	/** Arguments string as given by user or "" for no argument. */
-		char *args;
+	union { /**< driver-related part of device string. */
+		const char *args; /**< legacy name. */
 		const char *drv_str;
 	};
 	struct rte_bus *bus; /**< bus handle. */
 	struct rte_class *cls; /**< class handle. */
 	const char *bus_str; /**< bus-related part of device string. */
 	const char *cls_str; /**< class-related part of device string. */
-	const char *data; /**< Device string storage. */
+	char *data; /**< Scratch buffer. */
+	const char *src; /**< Arguments given by user. */
 };
 
 /**
@@ -145,6 +145,16 @@ rte_devargs_parsef(struct rte_devargs *da,
 		   const char *format, ...)
 __rte_format_printf(2, 0);
 
+/**
+ * Free resources in devargs.
+ *
+ * @param da
+ *   The devargs structure holding the device information.
+ */
+__rte_experimental
+void
+rte_devargs_free(struct rte_devargs *da);
+
 /**
  * Insert an rte_devargs in the global list.
  *
diff --git a/lib/librte_eal/rte_eal_exports.def b/lib/librte_eal/rte_eal_exports.def
index fe27bffe45..6fb1aaf8a8 100644
--- a/lib/librte_eal/rte_eal_exports.def
+++ b/lib/librte_eal/rte_eal_exports.def
@@ -29,6 +29,7 @@ EXPORTS
 	rte_devargs_next
 	rte_devargs_parse
 	rte_devargs_parsef
+	rte_devargs_free
 	rte_devargs_remove
 	rte_devargs_type_count
 	rte_dump_physmem_layout
diff --git a/lib/librte_eal/version.map b/lib/librte_eal/version.map
index b1db7ec795..ef388a30a1 100644
--- a/lib/librte_eal/version.map
+++ b/lib/librte_eal/version.map
@@ -409,6 +409,7 @@ EXPERIMENTAL {
 	rte_thread_tls_key_delete;
 	rte_thread_tls_value_get;
 	rte_thread_tls_value_set;
+	rte_devargs_free;
 };
 
 INTERNAL {
diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 17ddacc78d..325e7693eb 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -193,13 +193,14 @@ int
 rte_eth_iterator_init(struct rte_dev_iterator *iter, const char *devargs_str)
 {
 	int ret;
-	struct rte_devargs devargs = {.args = NULL};
+	struct rte_devargs devargs;
 	const char *bus_param_key;
 	char *bus_str = NULL;
 	char *cls_str = NULL;
 	int str_size;
 
 	memset(iter, 0, sizeof(*iter));
+	memset(&devargs, 0, sizeof(devargs));
 
 	/*
 	 * The devargs string may use various syntaxes:
@@ -244,8 +245,6 @@ rte_eth_iterator_init(struct rte_dev_iterator *iter, const char *devargs_str)
 		goto error;
 	}
 	iter->cls_str = cls_str;
-	free(devargs.args); /* allocated by rte_devargs_parse() */
-	devargs.args = NULL;
 
 	iter->bus = devargs.bus;
 	if (iter->bus->dev_iterate == NULL) {
@@ -284,7 +283,7 @@ rte_eth_iterator_init(struct rte_dev_iterator *iter, const char *devargs_str)
 	if (ret == -ENOTSUP)
 		RTE_ETHDEV_LOG(ERR, "Bus %s does not support iterating.\n",
 				iter->bus->name);
-	free(devargs.args);
+	rte_devargs_free(&devargs);
 	free(bus_str);
 	free(cls_str);
 	return ret;
-- 
2.25.1