Messages in this thread | | | Date | Wed, 10 Feb 2010 11:14:13 +0800 | Subject | Re: [PATCH] sysfs: differentiate between locking links and non-links | From | Américo Wang <> |
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On Wed, Feb 10, 2010 at 11:05 AM, David Rientjes <rientjes@google.com> wrote: > 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.
Yeah, basically, my fix is also adding a separate lockdep class, but at a different level. I will send the fix as soon as I finish it.
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