Messages in this thread | | | From | (Eric W. Biederman) | Date | Thu, 28 May 2009 08:45:32 -0700 | Subject | Re: [PATCH 25/20] sysfs: Only support removing emtpy sysfs directories. |
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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
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