rcu: Add a gcc-style structure initializer for RCU pointers
RCU_INIT_POINTER() returns a value that is never used, and which should
be abolished due to terminal ugliness:
q = RCU_INIT_POINTER(global_p, p);
However, there are two uses that cannot be handled by a do-while
formulation because they do gcc-style initialization:
RCU_INIT_POINTER(.real_cred, &init_cred),
RCU_INIT_POINTER(.cred, &init_cred),
This usage is clever, but not necessarily the nicest approach.
This commit therefore creates an RCU_POINTER_INITIALIZER() macro that
is specifically designed for gcc-style initialization.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>