[PATCH 2.6.23.12] net/bonding: option to specify initial bond interface number

[PATCH 2.6.23.12] net/bonding: option to specify initial bond interface number

[Jari Takkala]

Allow the user to specify an initial interface number when loading the bonding driver. This is useful when loading multiple instances of the bonding driver and you want to control the interface number assignment. For example, if the user wishes to create a bond5 interface they can type 'modprobe -o bond5 bonding ifnum=5'. It also works with the max_bonds option.

Signed-off-by: Jari Takkala <jari.takkala@q9.com>
---
diff -ruN linux-2.6.23.12.orig/drivers/net/bonding/bond_main.c linux-2.6.23.12/drivers/net/bonding/bond_main.c
--- linux-2.6.23.12.orig/drivers/net/bonding/bond_main.c	2007-12-18 16:55:57.000000000 -0500
+++ linux-2.6.23.12/drivers/net/bonding/bond_main.c	2008-01-02 14:49:37.000000000 -0500
@@ -85,6 +85,7 @@
 #define BOND_LINK_MON_INTERV	0
 #define BOND_LINK_ARP_INTERV	0
 
+static int ifnum	= BOND_DEFAULT_IFNUM;
 static int max_bonds	= BOND_DEFAULT_MAX_BONDS;
 static int miimon	= BOND_LINK_MON_INTERV;
 static int updelay	= 0;
@@ -99,6 +100,8 @@
 static char *arp_validate = NULL;
 struct bond_params bonding_defaults;
 
+module_param(ifnum, int, 0);
+MODULE_PARM_DESC(ifnum, "Initial interface number to assign");
 module_param(max_bonds, int, 0);
 MODULE_PARM_DESC(max_bonds, "Max number of bonded devices");
 module_param(miimon, int, 0);
@@ -4388,6 +4391,14 @@
 		}
 	}
 
+	if (ifnum < 0 || ifnum > INT_MAX) {
+		printk(KERN_WARNING DRV_NAME
+		       ": Warning: ifnum (%d) not in range %d-%d, so it "
+		       "was reset to BOND_DEFAULT_IFNUM (%d)\n",
+		       ifnum, 0, INT_MAX, BOND_DEFAULT_IFNUM);
+		ifnum = BOND_DEFAULT_IFNUM;
+	}
+
 	if (max_bonds < 1 || max_bonds > INT_MAX) {
 		printk(KERN_WARNING DRV_NAME
 		       ": Warning: max_bonds (%d) not in range %d-%d, so it "
@@ -4703,6 +4714,7 @@
 {
 	int i;
 	int res;
+	char ifname[16];
 
 	printk(KERN_INFO "%s", version);
 
@@ -4715,7 +4727,13 @@
 	bond_create_proc_dir();
 #endif
 	for (i = 0; i < max_bonds; i++) {
-		res = bond_create(NULL, &bonding_defaults, NULL);
+		if (ifnum != BOND_DEFAULT_IFNUM) {
+			ifnum = ifnum + i;
+			snprintf(ifname, sizeof(ifname) - 1, "bond%d", ifnum);
+			res = bond_create(ifname, &bonding_defaults, NULL);
+		} else {
+			res = bond_create(NULL, &bonding_defaults, NULL);
+		}
 		if (res)
 			goto err;
 	}
diff -ruN linux-2.6.23.12.orig/include/linux/if_bonding.h linux-2.6.23.12/include/linux/if_bonding.h
--- linux-2.6.23.12.orig/include/linux/if_bonding.h	2007-12-18 16:55:57.000000000 -0500
+++ linux-2.6.23.12/include/linux/if_bonding.h	2008-01-02 13:30:18.000000000 -0500
@@ -81,6 +81,7 @@
 #define BOND_STATE_ACTIVE       0   /* link is active */
 #define BOND_STATE_BACKUP       1   /* link is backup */
 
+#define BOND_DEFAULT_IFNUM	0   /* Default interface number */
 #define BOND_DEFAULT_MAX_BONDS  1   /* Default maximum number of devices to support */
 
 /* hashing types */

Re: [PATCH 2.6.23.12] net/bonding: option to specify initial bond interface number

[Randy Dunlap]

On Wed, 2 Jan 2008 16:20:48 -0500 Jari Takkala wrote:

> Allow the user to specify an initial interface number when loading the bonding driver. This is useful when loading multiple instances of the bonding driver and you want to control the interface number assignment. For example, if the user wishes to create a bond5 interface they can type 'modprobe -o bond5 bonding ifnum=5'. It also works with the max_bonds option.
> 
> Signed-off-by: Jari Takkala <jari.takkala@q9.com>
> ---
> diff -ruN linux-2.6.23.12.orig/drivers/net/bonding/bond_main.c linux-2.6.23.12/drivers/net/bonding/bond_main.c
> --- linux-2.6.23.12.orig/drivers/net/bonding/bond_main.c	2007-12-18 16:55:57.000000000 -0500
> +++ linux-2.6.23.12/drivers/net/bonding/bond_main.c	2008-01-02 14:49:37.000000000 -0500
> @@ -85,6 +85,7 @@
>  #define BOND_LINK_MON_INTERV	0
>  #define BOND_LINK_ARP_INTERV	0
>  
> +static int ifnum	= BOND_DEFAULT_IFNUM;
>  static int max_bonds	= BOND_DEFAULT_MAX_BONDS;
>  static int miimon	= BOND_LINK_MON_INTERV;
>  static int updelay	= 0;
> @@ -99,6 +100,8 @@
>  static char *arp_validate = NULL;
>  struct bond_params bonding_defaults;
>  
> +module_param(ifnum, int, 0);

You could (should) make <ifnum> be unsigned int and then use
module_param(ifnum, uint, 0);
and then ...

> +MODULE_PARM_DESC(ifnum, "Initial interface number to assign");
>  module_param(max_bonds, int, 0);
>  MODULE_PARM_DESC(max_bonds, "Max number of bonded devices");
>  module_param(miimon, int, 0);
> @@ -4388,6 +4391,14 @@
>  		}
>  	}

then this block is mostly useless since ifnum cannot be < 0.
And how could it ever be > INT_MAX (when ifnum was an int)?

If <ifnum> is unsigned int but you want to limit it to INT_MAX,
then half of this if-test would be OK.

> +	if (ifnum < 0 || ifnum > INT_MAX) {
> +		printk(KERN_WARNING DRV_NAME
> +		       ": Warning: ifnum (%d) not in range %d-%d, so it "
> +		       "was reset to BOND_DEFAULT_IFNUM (%d)\n",
> +		       ifnum, 0, INT_MAX, BOND_DEFAULT_IFNUM);
> +		ifnum = BOND_DEFAULT_IFNUM;
> +	}
> +
>  	if (max_bonds < 1 || max_bonds > INT_MAX) {
>  		printk(KERN_WARNING DRV_NAME
>  		       ": Warning: max_bonds (%d) not in range %d-%d, so it "


---
~Randy
desserts:  http://www.xenotime.net/linux/recipes/

RE: [PATCH 2.6.23.12] net/bonding: option to specify initial bond interface number

[Jari Takkala]

On Wednesday, January 02, 2008 16:56, Randy Dunlap wrote:
> You could (should) make <ifnum> be unsigned int and then use
> module_param(ifnum, uint, 0); and then ...
> 
> then this block is mostly useless since ifnum cannot be < 0.
> And how could it ever be > INT_MAX (when ifnum was an int)?
> 
> If <ifnum> is unsigned int but you want to limit it to INT_MAX,
> then half of this if-test would be OK.
> 

Thanks, that makes sense. I simply copied some of the max_bonds code which uses a signed int. I suppose that could be changed as well. I will post back a new patch.

Jari

Re: [PATCH 2.6.23.12] net/bonding: option to specify initial bond interface number

[Jay Vosburgh]

Jari Takkala <Jari.Takkala@Q9.com> wrote:

>Allow the user to specify an initial interface number when loading the bonding driver. This is useful when loading multiple instances of the bonding driver and you want to control the interface number assignment. For example, if the user wishes to create a bond5 interface they can type 'modprobe -o bond5 bonding ifnum=5'. It also works with the max_bonds option.

	What advantage does this have over:

# echo +bond5 > /sys/class/net/bonding_masters

	which will create a new bonding master for the already-loaded
driver?

	-J

---
	-Jay Vosburgh, IBM Linux Technology Center, fubar@us.ibm.com

RE: [PATCH 2.6.23.12] net/bonding: option to specify initial bond interface number

[Jari Takkala]

On Wednesday, January 02, 2008 17:24, Jay Vosburgh wrote:
> 	What advantage does this have over:
> 
> # echo +bond5 > /sys/class/net/bonding_masters
> 
> 	which will create a new bonding master for the already-loaded driver?
>

The advantage is that you can load multiple instances of the bonding driver and control the name of the bond interface that will be created. Normally the bond interface name would take the next available number.

In our startup scripts we need to be able to ensure that the interface name is consistent across reboots. Sometimes bond1 may be brought up before bond0 and it may have different options (requiring a different instance of the bonding driver).

I understand that the startup scripts could be modified to account for this, however we also have an IOS like interface to an embedded system where the user can create new bond interfaces and specify the interface number, they may create interfaces out of order and this feature enables them to accomplish that.

Jari

Re: [PATCH 2.6.23.12] net/bonding: option to specify initial bond interface number

[Jay Vosburgh]

Jari Takkala <Jari.Takkala@Q9.com> wrote:

>On Wednesday, January 02, 2008 17:24, Jay Vosburgh wrote:
>> 	What advantage does this have over:
>> 
>> # echo +bond5 > /sys/class/net/bonding_masters
>> 
>> 	which will create a new bonding master for the already-loaded driver?
>>
>
>The advantage is that you can load multiple instances of the bonding
>driver and control the name of the bond interface that will be
>created. Normally the bond interface name would take the next available
>number.
>
>In our startup scripts we need to be able to ensure that the interface
>name is consistent across reboots. Sometimes bond1 may be brought up
>before bond0 and it may have different options (requiring a different
>instance of the bonding driver).

	With the sysfs interface to bonding, your last statement is not
true; any number of bonding interfaces, with arbitrary names, can be
created and have their options set without loading multiple instances of
the bonding driver.

>I understand that the startup scripts could be modified to account for
>this, however we also have an IOS like interface to an embedded system
>where the user can create new bond interfaces and specify the interface
>number, they may create interfaces out of order and this feature enables
>them to accomplish that.

	Does your embedded system have sysfs available?  If it does,
then it's to your advantage to use the sysfs API; for one thing, the
single instance of the bonding driver with all interfaces through it
should utilize fewer resources than loading the driver repeatedly.

	-J

---
	-Jay Vosburgh, IBM Linux Technology Center, fubar@us.ibm.com

RE: [PATCH 2.6.23.12] net/bonding: option to specify initial bond interface number

[Jari Takkala]

On Thursday, January 03, 2008 12:04, Jay Vosburgh wrote:
>> In our startup scripts we need to be able to ensure that the
>> interface name is consistent across reboots. Sometimes bond1 may be
>> brought up before bond0 and it may have different options (requiring
>> a different instance of the bonding driver).
> 
> 	With the sysfs interface to bonding, your last statement is not
> true; any number of bonding interfaces, with arbitrary names, can be
> created and have their options set without loading multiple instances
> of the bonding driver.
> 
> 	Does your embedded system have sysfs available?  If it does,
> then it's to your advantage to use the sysfs API; for one thing, the
> single instance of the bonding driver with all interfaces through it
> should utilize fewer resources than loading the driver repeatedly.
> 

We do have sysfs available. I actually did not realize that it is possible to have one bonding instance and create multiple interfaces with different options. It looks like when I initially wrote this patch  (~2.6.20) either this feature was not available, or the bonding documentation may have been out of date. I see now in the latest Documentation/networking/bonding.txt that this is explained clearly.

Thank you for your help, I will drop the patch and move to using the sysfs method. Although I may need to patch it for our own uses to either not create bond0 on module load, or I may just run 'echo -bond0 > /sys/class/net/bonding_masters' immediately after loading the module.

Jari