Re: [PATCH 25/20] sysfs: Only support removing emtpy sysfs directories.

Eric W. Biederman
2009-05-28T15:45:53Z

Alan Stern <stern@rowland.harvard.edu> writes:

> There's another point to consider. If you do accept my argument that
> empty targets can be removed from visibility regardless of the host's
> state, then this removal races with addition of a new child. Since
> removal involves calling device_del(), it can't be protected by the
> host lock. Instead we'd have to use a mutex to protect both target
> addition and target removal.

Careful. Holding a lock over device_del is an easy and hidden way
to trigger a rare deadlocks.

Eric