Date:	Wed, 19 Nov 2014 13:41:49 +0100
From:	Jiri Pirko <jiri@...nulli.us>
To:	Hamad Kadmany <hkadmany@...eaurora.org>
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH] net: team: expose sysfs attributes for each team option

Wed, Nov 19, 2014 at 01:28:19PM CET, hkadmany@...eaurora.org wrote:
>On Mon, November 17, 2014 1:02 pm, Jiri Pirko wrote:
>>
>> Nak.
>>
>> I don't like this patch. The plan for team was keep things simple and to
>> have single userspace api using netlink, as that is the correct way to
>> deal with things. Sysfs for this use-case is not. Please, use netlink api.
>
>Using team driver requires using libnl3. In Android based platforms, libnl3 is not supported, and libnl3 license poses constraints in Android's user-space.

btw how about libteam? Does that poses the same constraints?


>
>This is the reason for the this change, to have at least the team options exposed through sysfs.
>
>
>>
>>>
>>>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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