From 6a5d088a923854569e20eac4f3f569926d5911ec Mon Sep 17 00:00:00 2001
From: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Date: Wed, 27 Aug 2014 16:27:30 +0300
Subject: [PATCH] carl9170: tx: Replace rcu_assign_pointer() with
RCU_INIT_POINTER()
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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 ârcu_dereference()â call and a
ârcu_assign_pointer()â 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>
---
drivers/net/wireless/ath/carl9170/tx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/carl9170/tx.c b/drivers/net/wireless/ath/carl9170/tx.c
index 4cadfd48ffdf8..ae86a600d9207 100644
--- a/drivers/net/wireless/ath/carl9170/tx.c
+++ b/drivers/net/wireless/ath/carl9170/tx.c
@@ -1557,7 +1557,7 @@ static struct carl9170_vif_info *carl9170_pick_beaconing_vif(struct ar9170 *ar)
}
out:
- rcu_assign_pointer(ar->beacon_iter, cvif);
+ RCU_INIT_POINTER(ar->beacon_iter, cvif);
return cvif;
}
--
2.39.5