Message-ID: <93856491220bda9aede41a9571fb1ac1.squirrel@www.codeaurora.org>
Date:	Mon, 17 Nov 2014 10:11:31 -0000
From:	"Hamad Kadmany" <hkadmany@...eaurora.org>
To:	jiri@...nulli.us
Cc:	netdev@...r.kernel.org
Subject: [PATCH] net: team: expose sysfs attributes for each team option

Current code provides only netlink API for user space
to read/write options. Exposing sysfs API is useful for
systems that don't have the required netlink
user space support.

Upon registration of team option, corresponding
sysfs attribute is created.

Signed-off-by: Hamad Kadmany <hkadmany@...eaurora.org>
---
 drivers/net/team/team.c | 282 ++++++++++++++++++++++++++++++++++++++++++++++--
 include/linux/if_team.h |   3 +
 2 files changed, 278 insertions(+), 7 deletions(-)

diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
index 1222229..afd2f8f 100644
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -110,8 +110,198 @@ struct team_option_inst { /* One for each option instance */
 	struct team_option_inst_info info;
 	bool changed;
 	bool removed;
+	bool dev_attr_file_exist;
+	struct device_attribute dev_attr; /* corresponding sysfs attribute */
 };

+static struct attribute *team_sysfs_attrs[] = {
+	NULL,
+};
+
+static struct attribute_group team_sysfs_attr_group = {
+	.attrs = team_sysfs_attrs,
+};
+
+/* Device attributes (sysfs) */
+
+static ssize_t show_attribute(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	struct team *team = dev_get_drvdata(dev);
+	struct team_option_inst *opt_inst;
+	ssize_t ret;
+	struct team_option *option;
+	struct team_gsetter_ctx ctx;
+
+	if (mutex_lock_interruptible(&team->lock))
+		return -ERESTARTSYS;
+
+	opt_inst = container_of(attr, struct team_option_inst, dev_attr);
+	option = opt_inst->option;
+	if (!option->getter) {
+		ret = -EOPNOTSUPP;
+		netdev_err(team->dev,
+			   "Option %s is write only\n", attr->attr.name);
+		goto exit;
+	}
+
+	ctx.info = &opt_inst->info;
+	/* let the option getter do its job */
+	ret = option->getter(team, &ctx);
+	if (ret)
+		goto exit;
+
+	/* translate option's output into sysfs output */
+	switch (option->type) {
+	case TEAM_OPTION_TYPE_U32:
+		ret = scnprintf(buf, PAGE_SIZE, "%u\n", ctx.data.u32_val);
+		break;
+	case TEAM_OPTION_TYPE_STRING:
+		ret = scnprintf(buf, PAGE_SIZE, "%s\n", ctx.data.str_val);
+		break;
+	case TEAM_OPTION_TYPE_BINARY:
+		if (ctx.data.bin_val.len > PAGE_SIZE) {
+			netdev_err(team->dev,
+				   "Option output is too long (%d)\n",
+				   ctx.data.bin_val.len);
+			break;
+		}
+
+		memcpy(buf, ctx.data.bin_val.ptr, ctx.data.bin_val.len);
+		ret = ctx.data.bin_val.len;
+		break;
+	case TEAM_OPTION_TYPE_BOOL:
+		ret = scnprintf(buf, PAGE_SIZE, "%d\n", ctx.data.bool_val);
+		break;
+	case TEAM_OPTION_TYPE_S32:
+		ret = scnprintf(buf, PAGE_SIZE, "%d\n", ctx.data.s32_val);
+		break;
+	default:
+		BUG();
+	}
+
+exit:
+	mutex_unlock(&team->lock);
+
+	return ret;
+}
+
+static int team_nl_send_event_options_get(struct team *team,
+					  struct list_head *sel_opt_inst_list);
+
+static ssize_t set_attribute(struct device *dev,
+			     struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct team_option_inst *opt_inst;
+	struct team *team = dev_get_drvdata(dev);
+	int err = 0;
+	struct team_option *option = NULL;
+	struct team_gsetter_ctx ctx;
+
+	LIST_HEAD(opt_inst_list);
+
+	if (mutex_lock_interruptible(&team->lock))
+		return -ERESTARTSYS;
+
+	opt_inst = container_of(attr, struct team_option_inst, dev_attr);
+	option = opt_inst->option;
+	if (!option->setter) {
+		netdev_err(team->dev,
+			   "Option %s is read only\n", attr->attr.name);
+		err = -EOPNOTSUPP;
+		goto exit;
+	}
+
+	ctx.info = &opt_inst->info;
+
+	/* translate sysfs input into option's input */
+	switch (option->type) {
+	case TEAM_OPTION_TYPE_U32:
+		err = kstrtoint(buf, 0, &ctx.data.u32_val);
+		break;
+	case TEAM_OPTION_TYPE_STRING:
+		if (count > TEAM_STRING_MAX_LEN) {
+			netdev_err(team->dev,
+				   "Input buffer too long (%zu)\n", count);
+			err = -EINVAL;
+			break;
+		}
+		ctx.data.str_val = buf;
+		break;
+	case TEAM_OPTION_TYPE_BINARY:
+		ctx.data.bin_val.len = count;
+		ctx.data.bin_val.ptr = buf;
+		break;
+	case TEAM_OPTION_TYPE_BOOL:
+		err = strtobool(buf, &ctx.data.bool_val);
+		break;
+	case TEAM_OPTION_TYPE_S32:
+		err = kstrtoint(buf, 0, &ctx.data.s32_val);
+		break;
+	default:
+		BUG();
+	}
+
+	if (err) {
+		netdev_err(team->dev, "Failed to translate input buffer\n");
+		goto exit;
+	}
+
+	/* let the option setter do its job */
+	err = option->setter(team, &ctx);
+	if (err)
+		goto exit;
+
+	/* propagate option changed event */
+	opt_inst->changed = true;
+	list_add(&opt_inst->tmp_list, &opt_inst_list);
+	err = team_nl_send_event_options_get(team, &opt_inst_list);
+	if (err == -ESRCH) /* no listeners, not a real error */
+		err = 0;
+
+exit:
+	mutex_unlock(&team->lock);
+
+	if (!err)
+		err = count;
+	return err;
+}
+
+/* create sysfs attribute for each option that is being registered */
+static int __team_option_add_sysfs_attr(struct team *team,
+					struct team_option_inst *opt_inst,
+					bool create_sysfs_file)
+{
+	int err = 0;
+	struct device_attribute *new_dev_attr = &opt_inst->dev_attr;
+
+	new_dev_attr->attr.name = opt_inst->option->name;
+	new_dev_attr->attr.mode = S_IRUGO | S_IWUSR;
+	new_dev_attr->show = show_attribute;
+	new_dev_attr->store = set_attribute;
+
+	if (create_sysfs_file) {
+		err = sysfs_create_file(&team->dev->dev.kobj,
+					&new_dev_attr->attr);
+		if (err)
+			netdev_err(team->dev,
+				   "Failed to create sysfs attribute %s\n",
+				   new_dev_attr->attr.name);
+	}
+
+	return err;
+}
+
+static void __team_option_del_sysfs_attr(struct team *team,
+					 struct team_option_inst *opt_inst)
+{
+	if (opt_inst->dev_attr_file_exist)
+		sysfs_remove_file(&team->dev->dev.kobj,
+				  &opt_inst->dev_attr.attr);
+}
+
 static struct team_option *__team_find_option(struct team *team,
 					      const char *opt_name)
 {
@@ -124,8 +314,10 @@ static struct team_option *__team_find_option(struct team *team,
 	return NULL;
 }

-static void __team_option_inst_del(struct team_option_inst *opt_inst)
+static void __team_option_inst_del(struct team *team,
+				   struct team_option_inst *opt_inst)
 {
+	__team_option_del_sysfs_attr(team, opt_inst);
 	list_del(&opt_inst->list);
 	kfree(opt_inst);
 }
@@ -137,7 +329,7 @@ static void __team_option_inst_del_option(struct team *team,

 	list_for_each_entry_safe(opt_inst, tmp, &team->option_inst_list, list) {
 		if (opt_inst->option == option)
-			__team_option_inst_del(opt_inst);
+			__team_option_inst_del(team, opt_inst);
 	}
 }

@@ -162,6 +354,7 @@ static int __team_option_inst_add(struct team *team, struct team_option *option,
 		opt_inst->info.array_index = i;
 		opt_inst->changed = true;
 		opt_inst->removed = false;
+		opt_inst->dev_attr_file_exist = false;
 		list_add_tail(&opt_inst->list, &team->option_inst_list);
 		if (option->init) {
 			err = option->init(team, &opt_inst->info);
@@ -170,6 +363,20 @@ static int __team_option_inst_add(struct team *team, struct team_option *option,
 		}

 	}
+
+	/* add sysfs attribute. per-port and array options are skipped */
+	if (!option->per_port && !option->array_size) {
+		/* create the sysfs file only if our state allows it */
+		bool create_sysfs_file = device_is_registered(&team->dev->dev);
+
+		err = __team_option_add_sysfs_attr(team, opt_inst,
+						   create_sysfs_file);
+		if (err)
+			return err;
+
+		opt_inst->dev_attr_file_exist = true;
+	}
+
 	return 0;
 }

@@ -218,7 +425,7 @@ static void __team_option_inst_del_port(struct team *team,
 	list_for_each_entry_safe(opt_inst, tmp, &team->option_inst_list, list) {
 		if (opt_inst->option->per_port &&
 		    opt_inst->info.port == port)
-			__team_option_inst_del(opt_inst);
+			__team_option_inst_del(team, opt_inst);
 	}
 }

@@ -337,6 +544,51 @@ static void __team_options_unregister(struct team *team,

 static void __team_options_change_check(struct team *team);

+static void team_attr_grp_free(struct team *team)
+{
+	kfree(team->attr_grp.attrs);
+}
+
+/* allocate attribute group for creating sysfs for team's own options */
+static int team_attr_grp_alloc(struct team *team)
+{
+	struct attribute **attributes;
+	struct team_option_inst *opt_inst;
+	int num_attr = 0;
+	struct team_option *option;
+
+	list_for_each_entry(opt_inst, &team->option_inst_list, list) {
+		option = opt_inst->option;
+		/* per-port and array options currently not supported as
+		 * sysfs attributes
+		 */
+		if (option->per_port || option->array_size)
+			continue;
+
+		num_attr++;
+	}
+
+	/* +1 for having NULL as last item in the array */
+	attributes = kzalloc((num_attr + 1) * sizeof(*attributes), GFP_KERNEL);
+	if (!attributes)
+		return -ENOMEM;
+	team->attr_grp.attrs = attributes;
+
+	num_attr = 0;
+	list_for_each_entry(opt_inst, &team->option_inst_list, list) {
+		option = opt_inst->option;
+		/* per-port and array options currently not supported as
+		 * sysfs attributes
+		 */
+		if (option->per_port || option->array_size)
+			continue;
+
+		attributes[num_attr++] = &opt_inst->dev_attr.attr;
+	}
+
+	return 0;
+}
+
 int team_options_register(struct team *team,
 			  const struct team_option *option,
 			  size_t option_count)
@@ -1380,15 +1632,28 @@ static int team_init(struct net_device *dev)

 	INIT_LIST_HEAD(&team->option_list);
 	INIT_LIST_HEAD(&team->option_inst_list);
-	err = team_options_register(team, team_options, ARRAY_SIZE(team_options));
+
+	err = team_options_register(team, team_options,
+				    ARRAY_SIZE(team_options));
 	if (err)
 		goto err_options_register;
 	netif_carrier_off(dev);

 	team_set_lockdep_class(dev);

+	/* store team context, to be used by Device attributes getter/setter */
+	dev_set_drvdata(&dev->dev, team);
+
+	/* allocate and register sysfs attributes for team's own options */
+	err = team_attr_grp_alloc(team);
+	if (err)
+		goto err_grp_alloc;
+	dev->sysfs_groups[0] = &team->attr_grp;
+
 	return 0;

+err_grp_alloc:
+	team_options_unregister(team, team_options, ARRAY_SIZE(team_options));
 err_options_register:
 	team_queue_override_fini(team);
 err_team_queue_override_init:
@@ -1407,9 +1672,15 @@ static void team_uninit(struct net_device *dev)
 	list_for_each_entry_safe(port, tmp, &team->port_list, list)
 		team_port_del(team, port->dev);

+	sysfs_remove_group(&team->dev->dev.kobj, &team->attr_grp);
+	team_attr_grp_free(team);
+	/* set to dummy group to avoid double free by core */
+	dev->sysfs_groups[0] = &team_sysfs_attr_group;
+
 	__team_change_mode(team, NULL); /* cleanup */
 	__team_options_unregister(team, team_options, ARRAY_SIZE(team_options));
 	team_queue_override_fini(team);
+
 	mutex_unlock(&team->lock);
 }

@@ -2194,9 +2465,6 @@ static int team_nl_cmd_options_get(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }

-static int team_nl_send_event_options_get(struct team *team,
-					  struct list_head *sel_opt_inst_list);
-
 static int team_nl_cmd_options_set(struct sk_buff *skb, struct genl_info *info)
 {
 	struct team *team;
diff --git a/include/linux/if_team.h b/include/linux/if_team.h
index 25b8b15..2e9fb2a 100644
--- a/include/linux/if_team.h
+++ b/include/linux/if_team.h
@@ -188,6 +188,9 @@ struct team {
 	struct list_head option_list;
 	struct list_head option_inst_list; /* list of option instances */

+	/* attribute group for registering team's own options at init */
+	struct attribute_group attr_grp;
+
 	const struct team_mode *mode;
 	struct team_mode_ops ops;
 	bool user_carrier_enabled;
-- 
1.8.5.2
-- 
Qualcomm Israel, on behalf of Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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