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documentation: Add lockless_dereference() 

The recently added lockless_dereference() macro is not present in the
Documentation/ directory, so this commit fixes that.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit is contained in:
Paul E. McKenney 2015-09-17 08:18:32 -07:00
parent b672adf8cf
commit ad2ad5d31f
1 changed files with 11 additions and 0 deletions
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11
Documentation/memory-barriers.txt
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@ -1710,6 +1710,17 @@ There are some more advanced barrier functions:
operations" subsection for information on where to use these. operations" subsection for information on where to use these.
(*) lockless_dereference();
This can be thought of as a pointer-fetch wrapper around the
smp_read_barrier_depends() data-dependency barrier.
This is also similar to rcu_dereference(), but in cases where
object lifetime is handled by some mechanism other than RCU, for
example, when the objects removed only when the system goes down.
In addition, lockless_dereference() is used in some data structures
that can be used both with and without RCU.
(*) dma_wmb(); (*) dma_wmb();
(*) dma_rmb(); (*) dma_rmb();