Messages in this thread |  | | Date | Tue, 9 Feb 2010 19:05:48 -0800 (PST) | From | David Rientjes <> | Subject | Re: [PATCH] sysfs: differentiate between locking links and non-links |
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On Wed, 10 Feb 2010, Américo Wang wrote:
> > What happens for hard links such as writing to > > /sys/devices/block/xxx/queue/scheduler to change an I/O scheduler which > > requires sd->dep_map and sd->parent->dep_map in sysfs_get_active_two() to > > pin both? The call to kobject_del() invokes the destruction that also > > requires sd->dep_map in sysfs_deactivate() because of the s_active lockdep > > annotation. > > > > This is not related with Neil's case at all. > > The I/O scheduler switch case should be a bogus, I am working on > it. We have more similar cases of cpu hotplug. Trust me, I am working > on a fix to all of them, this is not as easy as you may think about. >
You should be able to reuse Neil's sysfs_dirent_init_lockdep(sd, type) to seperate the lock classes for the sd getting pinned in sysfs_get_active_two() from sysfs_deactivate(), although using subclasses would probably be optimal since there is a clear parent -> child relationship. |  |