On Wed, 2009-08-19 at 13:56 -0500, Jordan_Hargrave@xxxxxxxx wrote: > This is from an old discussion several months ago: > http://lkml.org/lkml/2009/3/24/357 > http://lkml.org/lkml/2009/3/24/380 > > Basically the issue is that between a race in udev and PCI scan order the ethX IDs may not > be consistent between reboots. The idea is to use a mechanism similar to how disks now can > be accessed by their LABEL/PATH/UUID instead of raw /dev/sdX ids. > > example udev config: > SUBSYSTEM=="net", SYMLINK+="net/by-mac/$sysfs{ifindex}.$sysfs{address}" > SUBSYSTEM=="net", PROGRAM="/sbin/biosdevname -i %k --policy=all_names", SYMLINK+="net/by-chassis-id/%c" > > The following patch will create a device node for network devices based off their ifindex; > udev can then use this device node for creating symlinks in /dev/net/xxxx similar to the > way that disks now use by-label and by-path symlinks. > > Combining this with the biosdevname utility and patches to common network utilities, > it could be possible to access ethernet devices by their PCI path or BIOS Label. > > eg. ifconfig Embedded_NIC_1 Nice idea, but wouldn't it be "ifconfig LABEL=Embedded_NIC_1"? > --- include/linux/major.h~ 2009-07-30 18:34:47.000000000 -0400 > +++ include/linux/major.h 2009-08-05 14:52:10.000000000 -0400 > @@ -169,6 +169,7 @@ > #define IBM_FS3270_MAJOR 228 > > #define VIOTAPE_MAJOR 230 > +#define NETDEV_MAJOR 234 > > #define BLOCK_EXT_MAJOR 259 > #define SCSI_OSD_MAJOR 260 /* open-osd's OSD scsi device */ > --- net/core/net-sysfs.cx 2009-08-05 15:00:13.000000000 -0400 > +++ net/core/net-sysfs.c 2009-08-05 15:01:20.000000000 -0400 > @@ -11,6 +11,7 @@ > > #include <linux/capability.h> > #include <linux/kernel.h> > +#include <linux/major.h> > #include <linux/netdevice.h> > #include <linux/if_arp.h> > #include <net/sock.h> > @@ -496,6 +497,7 @@ int netdev_register_kobject(struct net_d > dev->class = &net_class; > dev->platform_data = net; > dev->groups = groups; > + dev->devt = MKDEV(NETDEV_MAJOR, net->ifindex); [...] Since this major number is unregistered, the device inode can only be stat'd and not open'd, which seems like a bit of a hack. Is there anything that would stop register_chrdev(0, ...) from allocating this major number, causing network devices to be confused with some other device type? Maybe there *should* be character devices for network device manipulation. It seems like that would avoid the race conditions that device renaming and removal causes for name-based socket ioctls. But maybe everyone should be using netlink for that instead. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
