Subject: Re: [PATCH net-next 1/2] bonding: add sysfs /slave dir for bond slave devices.

From: Ding Tianhong <[email-masked]>
Date: Thu, 16 Jan 2014 16:04:40 +0800

On 2014/1/16 13:54, Scott Feldman wrote:
> Add sub-directory under /sys/class/net/<interface>/slave with
> read-only attributes for slave.  Directory only appears when
> <interface> is a slave.
> 
> $ tree /sys/class/net/eth2/slave/
> /sys/class/net/eth2/slave/
> ├── ad_aggregator_id
> ├── link_failure_count
> ├── mii_status
> ├── perm_hwaddr
> ├── queue_id
> └── state
> 
> $ cat /sys/class/net/eth2/slave/*
> 2
> 0
> up
> 40:02:10:ef:06:01
> 0
> active
> 
> Signed-off-by: Scott Feldman <[email-masked]>
> ---
>  drivers/net/bonding/Makefile           |    2 
>  drivers/net/bonding/bond_main.c        |   27 ++++++
>  drivers/net/bonding/bond_procfs.c      |   12 ---
>  drivers/net/bonding/bond_sysfs_slave.c |  142 ++++++++++++++++++++++++++++++++
>  drivers/net/bonding/bonding.h          |    4 +
>  5 files changed, 174 insertions(+), 13 deletions(-)
>  create mode 100644 drivers/net/bonding/bond_sysfs_slave.c
> 
> diff --git a/drivers/net/bonding/Makefile b/drivers/net/bonding/Makefile
> index 5a5d720..6f4e808 100644
> --- a/drivers/net/bonding/Makefile
> +++ b/drivers/net/bonding/Makefile
> @@ -4,7 +4,7 @@
>  
>  obj-$(CONFIG_BONDING) += bonding.o
>  
> -bonding-objs := bond_main.o bond_3ad.o bond_alb.o bond_sysfs.o bond_debugfs.o bond_netlink.o bond_options.o
> +bonding-objs := bond_main.o bond_3ad.o bond_alb.o bond_sysfs.o bond_sysfs_slave.o bond_debugfs.o bond_netlink.o bond_options.o
>  
>  proc-$(CONFIG_PROC_FS) += bond_procfs.o
>  bonding-objs += $(proc-y)
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index f2fe6cb..4f1adae 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -466,6 +466,22 @@ static void bond_update_speed_duplex(struct slave *slave)
>  	return;
>  }
>  
> +const char *bond_slave_link_status(s8 link)
> +{
> +	switch (link) {
> +	case BOND_LINK_UP:
> +		return "up";
> +	case BOND_LINK_FAIL:
> +		return "going down";
> +	case BOND_LINK_DOWN:
> +		return "down";
> +	case BOND_LINK_BACK:
> +		return "going back";
> +	default:
> +		return "unknown";
> +	}
> +}
> +
>  /*
>   * if <dev> supports MII link status reporting, check its link status.
>   *
> @@ -1576,6 +1592,12 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
>  		goto err_unregister;
>  	}
>  
> +	res = bond_sysfs_slave_add(new_slave);
> +	if (res) {
> +		pr_debug("Error %d calling bond_sysfs_slave_add\n", res);
> +		goto err_upper_unlink;
> +	}
> +
>  	bond->slave_cnt++;
>  	bond_compute_features(bond);
>  	bond_set_carrier(bond);
> @@ -1595,6 +1617,9 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
>  	return 0;
>  
>  /* Undo stages on error */
> +err_upper_unlink:
> +	bond_upper_dev_unlink(bond_dev, slave_dev);
> +
>  err_unregister:
>  	netdev_rx_handler_unregister(slave_dev);
>  
> @@ -1687,6 +1712,8 @@ static int __bond_release_one(struct net_device *bond_dev,
>  	/* release the slave from its bond */
>  	bond->slave_cnt--;
>  
> +	bond_sysfs_slave_del(slave);
> +
>  	bond_upper_dev_unlink(bond_dev, slave_dev);
>  	/* unregister rx_handler early so bond_handle_frame wouldn't be called
>  	 * for this slave anymore.
> diff --git a/drivers/net/bonding/bond_procfs.c b/drivers/net/bonding/bond_procfs.c
> index fb868d6..8515b344 100644
> --- a/drivers/net/bonding/bond_procfs.c
> +++ b/drivers/net/bonding/bond_procfs.c
> @@ -159,18 +159,6 @@ static void bond_info_show_master(struct seq_file *seq)
>  	}
>  }
>  
> -static const char *bond_slave_link_status(s8 link)
> -{
> -	static const char * const status[] = {
> -		[BOND_LINK_UP] = "up",
> -		[BOND_LINK_FAIL] = "going down",
> -		[BOND_LINK_DOWN] = "down",
> -		[BOND_LINK_BACK] = "going back",
> -	};
> -
> -	return status[link];
> -}
> -
>  static void bond_info_show_slave(struct seq_file *seq,
>  				 const struct slave *slave)
>  {
> diff --git a/drivers/net/bonding/bond_sysfs_slave.c b/drivers/net/bonding/bond_sysfs_slave.c
> new file mode 100644
> index 0000000..28390af
> --- /dev/null
> +++ b/drivers/net/bonding/bond_sysfs_slave.c
> @@ -0,0 +1,142 @@
> +/*	Sysfs attributes of bond slaves
> + *
> + *      Copyright (c) 2014 Scott Feldman <[email-masked]>
> + *
> + *	This program is free software; you can redistribute it and/or
> + *	modify it under the terms of the GNU General Public License
> + *	as published by the Free Software Foundation; either version
> + *	2 of the License, or (at your option) any later version.
> + */
> +
> +#include <linux/capability.h>
> +#include <linux/kernel.h>
> +#include <linux/netdevice.h>
> +
> +#include "bonding.h"
> +
> +struct slave_attribute {
> +	struct attribute attr;
> +	ssize_t (*show)(struct slave *, char *);
> +};
> +
> +#define SLAVE_ATTR(_name, _mode, _show)				\
> +const struct slave_attribute slave_attr_##_name = {		\
> +	.attr = {.name = __stringify(_name),			\
> +		 .mode = _mode },				\
> +	.show	= _show,					\
> +};
> +#define SLAVE_ATTR_RO(_name) \
> +	SLAVE_ATTR(_name, S_IRUGO, _name##_show)
> +
> +static ssize_t state_show(struct slave *slave, char *buf)
> +{
> +	switch (bond_slave_state(slave)) {
> +	case BOND_STATE_ACTIVE:
> +		return sprintf(buf, "active\n");
> +	case BOND_STATE_BACKUP:
> +		return sprintf(buf, "backup\n");
> +	default:
> +		return sprintf(buf, "UNKONWN\n");
> +	}
> +}
> +static SLAVE_ATTR_RO(state);
> +
> +static ssize_t mii_status_show(struct slave *slave, char *buf)
> +{
> +	return sprintf(buf, "%s\n", bond_slave_link_status(slave->link));
> +}
> +static SLAVE_ATTR_RO(mii_status);
> +
> +static ssize_t link_failure_count_show(struct slave *slave, char *buf)
> +{
> +	return sprintf(buf, "%d\n", slave->link_failure_count);
> +}
> +static SLAVE_ATTR_RO(link_failure_count);
> +
> +static ssize_t perm_hwaddr_show(struct slave *slave, char *buf)
> +{
> +	return sprintf(buf, "%pM\n", slave->perm_hwaddr);
> +}
> +static SLAVE_ATTR_RO(perm_hwaddr);
> +
> +static ssize_t queue_id_show(struct slave *slave, char *buf)
> +{
> +	return sprintf(buf, "%d\n", slave->queue_id);
> +}
> +static SLAVE_ATTR_RO(queue_id);
> +
> +static ssize_t ad_aggregator_id_show(struct slave *slave, char *buf)
> +{
> +	const struct aggregator *agg;
> +
> +	if (slave->bond->params.mode == BOND_MODE_8023AD) {
> +		agg = SLAVE_AD_INFO(slave).port.aggregator;
> +		if (agg)
> +			return sprintf(buf, "%d\n",
> +				       agg->aggregator_identifier);
> +	}
> +
> +	return sprintf(buf, "N/A\n");
> +}
> +static SLAVE_ATTR_RO(ad_aggregator_id);
> +
> +static const struct slave_attribute *slave_attrs[] = {
> +	&slave_attr_state,
> +	&slave_attr_mii_status,
> +	&slave_attr_link_failure_count,
> +	&slave_attr_perm_hwaddr,
> +	&slave_attr_queue_id,
> +	&slave_attr_ad_aggregator_id,
> +	NULL
> +};
> +
> +#define to_slave_attr(_at) container_of(_at, struct slave_attribute, attr)
> +#define to_slave(obj)	container_of(obj, struct slave, kobj)
> +
> +static ssize_t slave_show(struct kobject *kobj,
> +			  struct attribute *attr, char *buf)
> +{
> +	struct slave_attribute *slave_attr = to_slave_attr(attr);
> +	struct slave *slave = to_slave(kobj);
> +
> +	return slave_attr->show(slave, buf);
> +}
> +
> +const struct sysfs_ops slave_sysfs_ops = {
> +	.show = slave_show,
> +};
> +
> +static struct kobj_type slave_ktype = {
> +#ifdef CONFIG_SYSFS
> +	.sysfs_ops = &slave_sysfs_ops,
> +#endif
> +};
> +
> +int bond_sysfs_slave_add(struct slave *slave)
> +{
> +	const struct slave_attribute **a;
> +	int err;
> +
> +	err = kobject_init_and_add(&slave->kobj, &slave_ktype,
> +				   &(slave->dev->dev.kobj), "slave");
> +	if (err)
> +		return err;
> +
> +	for (a = slave_attrs; *a; ++a) {
> +		err = sysfs_create_file(&slave->kobj, &((*a)->attr));
> +		if (err)
> +			return err;
> +	}
> +
I think if add rollback path if create failed, it will be better.

Regards
Ding 

> +	return 0;
> +}
> +
> +void bond_sysfs_slave_del(struct slave *slave)
> +{
> +	const struct slave_attribute **a;
> +
> +	for (a = slave_attrs; *a; ++a)
> +		sysfs_remove_file(&slave->kobj, &((*a)->attr));
> +
> +	kobject_del(&slave->kobj);
> +}
> diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
> index 955dc48..309757d 100644
> --- a/drivers/net/bonding/bonding.h
> +++ b/drivers/net/bonding/bonding.h
> @@ -203,6 +203,7 @@ struct slave {
>  #ifdef CONFIG_NET_POLL_CONTROLLER
>  	struct netpoll *np;
>  #endif
> +	struct kobject kobj;
>  };
>  
>  /*
> @@ -421,6 +422,8 @@ int bond_create(struct net *net, const char *name);
>  int bond_create_sysfs(struct bond_net *net);
>  void bond_destroy_sysfs(struct bond_net *net);
>  void bond_prepare_sysfs_group(struct bonding *bond);
> +int bond_sysfs_slave_add(struct slave *slave);
> +void bond_sysfs_slave_del(struct slave *slave);
>  int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev);
>  int bond_release(struct net_device *bond_dev, struct net_device *slave_dev);
>  int bond_xmit_hash(struct bonding *bond, struct sk_buff *skb, int count);
> @@ -469,6 +472,7 @@ int bond_option_lacp_rate_set(struct bonding *bond, int lacp_rate);
>  int bond_option_ad_select_set(struct bonding *bond, int ad_select);
>  struct net_device *bond_option_active_slave_get_rcu(struct bonding *bond);
>  struct net_device *bond_option_active_slave_get(struct bonding *bond);
> +const char *bond_slave_link_status(s8 link);
>  
>  struct bond_net {
>  	struct net *		net;	/* Associated network namespace */
> 
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