Subject: [PATCH v2] net/mac80211/mesh_plink: Convert timers to use timer_setup()

From: Kees Cook <[email-masked]>
Date: Thu, 5 Oct 2017 10:39:10 -0700

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly. This requires adding a pointer back
to the sta_info since container_of() can't resolve the sta_info.

Cc: Johannes Berg <[email-masked]>
Cc: "David S. Miller" <[email-masked]>
Cc: [email-masked]
Cc: [email-masked]
Cc: Thomas Gleixner <[email-masked]>
Signed-off-by: Kees Cook <[email-masked]>
---
This requires commit 686fef928bba ("timer: Prepare to change timer
callback argument type") in v4.14-rc3, but should be otherwise
stand-alone.

v2:
- make mesh_plink_timer non-static and use it in timer_setup() call directly.
---
 net/mac80211/mesh.h       |  1 +
 net/mac80211/mesh_plink.c | 10 ++++------
 net/mac80211/sta_info.c   |  4 +++-
 net/mac80211/sta_info.h   |  2 ++
 4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h
index 7e5f271e3c30..465b7853edc0 100644
--- a/net/mac80211/mesh.h
+++ b/net/mac80211/mesh.h
@@ -275,6 +275,7 @@ void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 			   u8 *hw_addr, struct ieee802_11_elems *ie);
 bool mesh_peer_accepts_plinks(struct ieee802_11_elems *ie);
 u32 mesh_accept_plinks_update(struct ieee80211_sub_if_data *sdata);
+void mesh_plink_timer(struct timer_list *t);
 void mesh_plink_broken(struct sta_info *sta);
 u32 mesh_plink_deactivate(struct sta_info *sta);
 u32 mesh_plink_open(struct sta_info *sta);
diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index f69c6c38ca43..e79adb4164f3 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -604,8 +604,9 @@ void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 	ieee80211_mbss_info_change_notify(sdata, changed);
 }
 
-static void mesh_plink_timer(unsigned long data)
+void mesh_plink_timer(struct timer_list *t)
 {
+	struct mesh_sta *mesh = from_timer(mesh, t, plink_timer);
 	struct sta_info *sta;
 	u16 reason = 0;
 	struct ieee80211_sub_if_data *sdata;
@@ -617,7 +618,7 @@ static void mesh_plink_timer(unsigned long data)
 	 * del_timer_sync() this timer after having made sure
 	 * it cannot be readded (by deleting the plink.)
 	 */
-	sta = (struct sta_info *) data;
+	sta = mesh->plink_sta;
 
 	if (sta->sdata->local->quiescing)
 		return;
@@ -697,11 +698,8 @@ static void mesh_plink_timer(unsigned long data)
 
 static inline void mesh_plink_timer_set(struct sta_info *sta, u32 timeout)
 {
-	sta->mesh->plink_timer.expires = jiffies + msecs_to_jiffies(timeout);
-	sta->mesh->plink_timer.data = (unsigned long) sta;
-	sta->mesh->plink_timer.function = mesh_plink_timer;
 	sta->mesh->plink_timeout = timeout;
-	add_timer(&sta->mesh->plink_timer);
+	mod_timer(&sta->mesh->plink_timer, jiffies + msecs_to_jiffies(timeout));
 }
 
 static bool llid_in_use(struct ieee80211_sub_if_data *sdata,
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 69615016d5bf..6c254a9d5f11 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -329,10 +329,12 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
 		sta->mesh = kzalloc(sizeof(*sta->mesh), gfp);
 		if (!sta->mesh)
 			goto free;
+		sta->mesh->plink_sta = sta;
 		spin_lock_init(&sta->mesh->plink_lock);
 		if (ieee80211_vif_is_mesh(&sdata->vif) &&
 		    !sdata->u.mesh.user_mpm)
-			init_timer(&sta->mesh->plink_timer);
+			timer_setup(&sta->mesh->plink_timer, mesh_plink_timer,
+				    0);
 		sta->mesh->nonpeer_pm = NL80211_MESH_POWER_ACTIVE;
 	}
 #endif
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 3acbdfa9f649..21d9760ce5c3 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -344,6 +344,7 @@ DECLARE_EWMA(mesh_fail_avg, 20, 8)
  * @plink_state: peer link state
  * @plink_timeout: timeout of peer link
  * @plink_timer: peer link watch timer
+ * @plink_sta: peer link watch timer's sta_info
  * @t_offset: timing offset relative to this host
  * @t_offset_setpoint: reference timing offset of this sta to be used when
  * 	calculating clockdrift
@@ -356,6 +357,7 @@ DECLARE_EWMA(mesh_fail_avg, 20, 8)
  */
 struct mesh_sta {
 	struct timer_list plink_timer;
+	struct sta_info *plink_sta;
 
 	s64 t_offset;
 	s64 t_offset_setpoint;
-- 
2.7.4

-- 
Kees Cook
Pixel Security