doc: Update rcu_assign_pointer() definition in whatisRCU.txt

The rcu_assign_pointer() macro has changed over time, and the version
in Documentation/RCU/whatisRCU.txt has not kept up.  This commit brings
it into 2017, albeit in a simplified fashion.

Reported-by: Andrea Parri <parri.andrea@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2017-03-07 07:30:58 -08:00
parent 6771853bce
commit 066bb1c84a
1 changed files with 13 additions and 12 deletions

View File

@ -587,16 +587,17 @@ It is extremely simple:
write_unlock(&rcu_gp_mutex);
}
[You can ignore rcu_assign_pointer() and rcu_dereference() without
missing much. But here they are anyway. And whatever you do, don't
forget about them when submitting patches making use of RCU!]
[You can ignore rcu_assign_pointer() and rcu_dereference() without missing
much. But here are simplified versions anyway. And whatever you do,
don't forget about them when submitting patches making use of RCU!]
#define rcu_assign_pointer(p, v) ({ \
smp_wmb(); \
(p) = (v); \
#define rcu_assign_pointer(p, v) \
({ \
smp_store_release(&(p), (v)); \
})
#define rcu_dereference(p) ({ \
#define rcu_dereference(p) \
({ \
typeof(p) _________p1 = p; \
smp_read_barrier_depends(); \
(_________p1); \