count: Don't in-place increment a READ_ONCE()

This commit prohibits READ_ONCE(x)++ and fixes the occurrence of this
in count_state_eventual.c.

Reported-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
4 files changed