According to RCU_INIT_POINTER()'s block comment 3.a, it can be used if
"3. The referenced data structure has already been exposed to readers either
at compile time or via rcu_assign_pointer() -and-
a. You have not made -any- reader-visible changes to this structure since
then".
This case fulfills the conditions above because between the rcu_dereference()
call (cvif = rcu_dereference(ar->beacon_iter);) and the rcu_assign_pointer()
call there is no update of the "cvif" variable.
Therefore, this patch makes the replacement.
The following Coccinelle semantic patch was used:
@@
identifier v;
@@
v = rcu_dereference(...);
... when != rcu_dereference(...);
when != v = ...;
when != (<+...v...+>)++;
when != \(memcpy\|memset\)(...);
(
- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., v);
|
if(...) {
... when != v = ...;
- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., v);
... when any
}
)
Because there are cases where between a “rcu_dereference()” call and a
“rcu_assign_pointer()” call might be updates of the value that interests us,
the Coccinelle semantic patch ignores them and replaces with
"RCU_INIT_POINTER()" only when the update is not happening.
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Acked-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
6a5d088a92