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

[Alan Stern]

On Thu, 28 May 2009, Eric W. Biederman wrote:

> Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> 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.

Your point is well taken.  In addition, I don't really like the idea of 
forcing device removal to wait for some other device to be added.

I'll work around the problem somehow...  A short polling loop shoud do 
the job.

Alan Stern

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