Subject: Re: [-net, v2, 2/2] bonding: fix bond_arp_rcv setting and arp validate desync state

From: Veaceslav Falico <[email-masked]>
Date: Tue, 10 Sep 2013 20:20:00 +0200

On Sat, Sep 07, 2013 at 12:00:26AM +0200, [email-masked] wrote:
>We make bond_arp_rcv global so it can be used in bond_sysfs if the bond
>interface is up and arp_interval is being changed to a positive value
>and cleared otherwise as per Jay's suggestion.
>This also fixes a problem where bond_arp_rcv was set even though
>arp_validate was disabled while the bond was up by unsetting recv_probe
>in bond_store_arp_validate and respectively setting it if enabled.
>
>Signed-off-by: Nikolay Aleksandrov <[email-masked]>
>Signed-off-by: Marcelo Ricardo Leitner <[email-masked]>
>
>---
>v2: fix the mode check in store_arp_validate
>I've intentionally left the prototype line >80 chars, let me know if I
>should break it.
>
> drivers/net/bonding/bond_main.c  |  4 ++--
> drivers/net/bonding/bond_sysfs.c | 19 ++++++++++++++++---
> drivers/net/bonding/bonding.h    |  1 +
> 3 files changed, 19 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 39e5b1c..72df399 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -2404,8 +2404,8 @@ static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32
> 	slave->target_last_arp_rx[i] = jiffies;
> }
>
>-static int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond,
>-			struct slave *slave)
>+int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond,
>+		 struct slave *slave)
> {
> 	struct arphdr *arp = (struct arphdr *)skb->data;
> 	unsigned char *arp_ptr;
>diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
>index 4e38683..eeab40b 100644
>--- a/drivers/net/bonding/bond_sysfs.c
>+++ b/drivers/net/bonding/bond_sysfs.c
>@@ -349,6 +349,8 @@ static ssize_t bonding_store_mode(struct device *d,
> 		goto out;
> 	}
>
>+	/* don't cache arp_validate between modes */
>+	bond->params.arp_validate = BOND_ARP_VALIDATE_NONE;
> 	bond->params.mode = new_value;
> 	bond_set_mode_ops(bond, bond->params.mode);
> 	pr_info("%s: setting mode to %s (%d).\n",
>@@ -419,8 +421,8 @@ static ssize_t bonding_store_arp_validate(struct device *d,
> 					  struct device_attribute *attr,
> 					  const char *buf, size_t count)
> {
>-	int new_value, ret = count;
> 	struct bonding *bond = to_bond(d);
>+	int new_value, ret = count;

Ah, so you've made it in the second patch, sorry, didn't notice.

>
> 	if (!rtnl_trylock())
> 		return restart_syscall();
>@@ -431,7 +433,7 @@ static ssize_t bonding_store_arp_validate(struct device *d,
> 		ret = -EINVAL;
> 		goto out;
> 	}
>-	if (new_value && (bond->params.mode != BOND_MODE_ACTIVEBACKUP)) {
>+	if (bond->params.mode != BOND_MODE_ACTIVEBACKUP) {
> 		pr_err("%s: arp_validate only supported in active-backup mode.\n",
> 		       bond->dev->name);
> 		ret = -EINVAL;
>@@ -441,6 +443,12 @@ static ssize_t bonding_store_arp_validate(struct device *d,
> 		bond->dev->name, arp_validate_tbl[new_value].modename,
> 		new_value);
>
>+	if (bond->dev->flags & IFF_UP) {
>+		if (!new_value)
>+			bond->recv_probe = NULL;
>+		else if (bond->params.arp_interval)
>+			bond->recv_probe = bond_arp_rcv;
>+	}
> 	bond->params.arp_validate = new_value;
> out:
> 	rtnl_unlock();
>@@ -561,8 +569,8 @@ static ssize_t bonding_store_arp_interval(struct device *d,
> 					  struct device_attribute *attr,
> 					  const char *buf, size_t count)
> {
>-	int new_value, ret = count;
> 	struct bonding *bond = to_bond(d);
>+	int new_value, ret = count;
>
> 	if (!rtnl_trylock())
> 		return restart_syscall();
>@@ -605,8 +613,13 @@ static ssize_t bonding_store_arp_interval(struct device *d,
> 		 * is called.
> 		 */
> 		if (!new_value) {
>+			if (bond->params.arp_validate)
>+				bond->recv_probe = NULL;
> 			cancel_delayed_work_sync(&bond->arp_work);
> 		} else {
>+			/* arp_validate can be set only in active-backup mode */
>+			if (bond->params.arp_validate)
>+				bond->recv_probe = bond_arp_rcv;

This whole juggling is really annoying, however it's indeed the best way we
can fix now.

Thanks Nik.

Acked-by: Veaceslav Falico <[email-masked]>

> 			cancel_delayed_work_sync(&bond->mii_work);
> 			queue_delayed_work(bond->wq, &bond->arp_work, 0);
> 		}
>diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
>index f7ab161..7ad8bd5 100644
>--- a/drivers/net/bonding/bonding.h
>+++ b/drivers/net/bonding/bonding.h
>@@ -430,6 +430,7 @@ static inline bool slave_can_tx(struct slave *slave)
>
> struct bond_net;
>
>+int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond, struct slave *slave);
> struct vlan_entry *bond_next_vlan(struct bonding *bond, struct vlan_entry *curr);
> int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb, struct net_device *slave_dev);
> void bond_xmit_slave_id(struct bonding *bond, struct sk_buff *skb, int slave_id);