Messages in this thread | | | Date | Thu, 28 May 2009 13:51:39 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [PATCH 25/20] sysfs: Only support removing emtpy sysfs directories. |
| |
On Thu, 28 May 2009, Eric W. Biederman wrote:
> 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.
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
| |