Annotates ieee80211_set_beacon_cntdwn() with a __must_hold() annotation to
make it clear that ieee80211_set_beacon_cntdwn() is only intended to be
called when the caller has a lock on the argument "link."
Signed-off-by: Brent Pappas <bpappas@xxxxxxxxxxxxxxx>
---
Currently, ieee80211_set_beacon_cntdwn() calls rcu_dereference(), but
without calling rcu_read_lock() beforehand and rcu_read_unlock()
afterward. At first I thought this was a bug, since (if I understand the
RCU API correctly) rcu_dereference() should only be called in RCU
read-side critical sections. However, upon closer inspection of the code,
I realized that ieee80211_set_beacon_cntdwn() is only ever called inside
critical sections. Therefore it seems appropriate to me to annotate
ieee80211_set_beacon_cntdwn() with a __must_hold() annotation to make this
apparent precondition explicit.
This is my first time submitting an RCU-related patch so please tell me if
I am misunderstanding the RCU API.
net/mac80211/tx.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 314998fdb1a5..7245f2e641ba 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -10,6 +10,7 @@
* Transmit and frame generation functions.
*/
+#include "linux/compiler_types.h"
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
@@ -4974,6 +4975,7 @@ static int ieee80211_beacon_add_tim(struct ieee80211_sub_if_data *sdata,
static void ieee80211_set_beacon_cntdwn(struct ieee80211_sub_if_data *sdata,
struct beacon_data *beacon,
struct ieee80211_link_data *link)
+ __must_hold(link)
{
u8 *beacon_data, count, max_count = 1;
struct probe_resp *resp;
--
2.43.0
