net/mac80211/mesh_plink: Convert timers to use timer_setup()

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 <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

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);

net/mac80211/mesh_plink.c

@@ -603,8 +603,9 @@ 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;
@@ -616,7 +617,7 @@ 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;
@@ -696,11 +697,8 @@ 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,

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

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;