Dne 25.7.2011 02:18, Kay Sievers napsal(a): > On Fri, 2011-07-22 at 16:22 +0200, Zdenek Kabelac wrote: > >> For now udev recieves 3 event for removal of DM logical volumes. (1 for >> bdi and 2 for same block kobject). Reason is dm device generates its >> own kobject event with approriate env parameter and block layer sends >> another KOBJ_REMOVE event on its own unconditionaly for the same >> kobject. As for now only the kobject cleanup checks that the REMOVE >> event has been already sent and avoids duplicate REMOVE event. > >> The patch for kobject_uevent_env() which has been testing for duplicate >> REMOVE event did not passed into the mainline (yet?): > > No, it's wasn't merged. Subsystems should really not send their own > 'add' or 'remove' events. These are properties of the driver core. > >> I'm proposing alternative way around to always use kobject cleanup >> routine for sending REMOVE event if it was not send by the module - so >> it makes the code few lines shorter. > > The events the core creates are only sent out at release() not at del(), > so we would delay 'remove' events when we keep the device pinned but > it's not valid anymore. We can not do that today, we would need to move > the core-created 'remove' events to del(). > > > For device-mapper, I would prefer to add a '.dev_uevent' callback to the > 'block' class let this callback check 'struct block_device_operations' > for a possibly specified '.uevent' callback and call it. > > Then have 'dm_blk_dops' add '.uevent' and let the core call into the dm > code to the needed properties to the 'remove' event, instead of sending > its own, and see the duplication. Sounds like complex solution - maybe it would be easier to just register some environment variable on dm code side - like kobject_add_env() - so it would take envs from this internal kobject list and after sending uevent it would implicitly clear this list. So in dm case dm-uevent would just register env(cookie) for KOBJ_REMOVE and would left kobject_uevent() on block layer ? Also I'm aware that remove event would be delayed by leaving it on kobject_cleanup(), but since you mentioned 'del()' as a better place - why not move this implicit uvent call there - since most kernel driver writers probably do not want to be bothered with uvents? Zdenek -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
