| Date | Fri, 11 Dec 2009 14:01:17 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [patch 8/9] Documentation: Fix invalid rcu assumptions |
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On Fri, Dec 11, 2009 at 09:28:25PM +0000, Arnd Bergmann wrote: > On Thursday 10 December 2009 00:53:26 Thomas Gleixner wrote: > > Index: linux-2.6-tip/Documentation/credentials.txt > > =================================================================== > > --- linux-2.6-tip.orig/Documentation/credentials.txt > > +++ linux-2.6-tip/Documentation/credentials.txt > > @@ -408,9 +408,6 @@ This should be used inside the RCU read > > ... > > } > > > > -A function need not get RCU read lock to use __task_cred() if it is holding a > > -spinlock at the time as this implicitly holds the RCU read lock. > > - > > Should it be necessary to hold another task's credentials for a long period of > > time, and possibly to sleep whilst doing so, then the caller should get a > > reference on them using: > > How about changing the documentation to explain why you can't just use a spinlock > or local_irq_disable instead of rcu_read_lock? You explained it well in your > [patch 0/9], but that part had not occurred to me yet and having it in the kernel > sources might prevent more people from getting it wrong in the future.
That does make a lot of sense... Will add that in.
Thanx, Paul
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