rcu: Make rcu_assign_pointer's assignment volatile and type-safe
rcu_assign_pointer needs to use ACCESS_ONCE to make the assignment to
the destination pointer volatile, to protect against compilers too
clever for their own good.
In addition, since rcu_assign_pointer force-casts the source pointer to
add the __rcu address space (overriding any existing address space), add
an explicit check that the source pointer has the __kernel address space
to start with.
This new check produces warnings like this, when attempting to assign
from a __user pointer:
test.c:25:9: warning: incorrect type in argument 2 (different address spaces)
test.c:25:9: expected struct foo *<noident>
test.c:25:9: got struct foo [noderef] <asn:1>*badsrc
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
1 file changed
