diff options
| -rw-r--r-- | drivers/base/core.c | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 080e9ca..9cd3b5c 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1551,7 +1551,34 @@ EXPORT_SYMBOL_GPL(device_destroy); * on the same device to ensure that new_name is valid and * won't conflict with other devices. * - * "Never use this function, bad things will happen" - gregkh + * Note: Don't call this function. Currently, the networking layer calls this + * function, but that will change. The following text from Kay Sievers offers + * some insight: + * + * Renaming devices is racy at many levels, symlinks and other stuff are not + * replaced atomically, and you get a "move" uevent, but it's not easy to + * connect the event to the old and new device. Device nodes are not renamed at + * all, there isn't even support for that in the kernel now. + * + * In the meantime, during renaming, your target name might be taken by another + * driver, creating conflicts. Or the old name is taken directly after you + * renamed it -- then you get events for the same DEVPATH, before you even see + * the "move" event. It's just a mess, and nothing new should ever rely on + * kernel device renaming. Besides that, it's not even implemented now for + * other things than (driver-core wise very simple) network devices. + * + * We are currently about to change network renaming in udev to completely + * disallow renaming of devices in the same namespace as the kernel uses, + * because we can't solve the problems properly, that arise with swapping names + * of multiple interfaces without races. Means, renaming of eth[0-9]* will only + * be allowed to some other name than eth[0-9]*, for the aforementioned + * reasons. + * + * Make up a "real" name in the driver before you register anything, or add + * some other attributes for userspace to find the device, or use udev to add + * symlinks -- but never rename kernel devices later, it's a complete mess. We + * don't even want to get into that and try to implement the missing pieces in + * the core. We really have other pieces to fix in the driver core mess. :) */ int device_rename(struct device *dev, const char *new_name) { |
