#include <net/mac80211.h>
#include "ieee80211_i.h"
-#include "ieee80211_rate.h"
+#include "rate.h"
#include "sta_info.h"
#include "debugfs_sta.h"
#include "mesh.h"
*
* In order to remove a STA info structure, the caller needs to first
* unlink it (sta_info_unlink()) from the list and hash tables and
- * then destroy it while holding the RTNL; sta_info_destroy() will wait
- * for an RCU grace period to elapse before actually freeing it. Due to
- * the pinning and the possibility of multiple callers trying to remove
- * the same STA info at the same time, sta_info_unlink() can clear the
- * STA info pointer it is passed to indicate that the STA info is owned
- * by somebody else now.
+ * then destroy it; sta_info_destroy() will wait for an RCU grace period
+ * to elapse before actually freeing it. Due to the pinning and the
+ * possibility of multiple callers trying to remove the same STA info at
+ * the same time, sta_info_unlink() can clear the STA info pointer it is
+ * passed to indicate that the STA info is owned by somebody else now.
*
* If sta_info_unlink() did not clear the pointer then the caller owns
* the STA info structure now and is responsible of destroying it with
- * a call to sta_info_destroy(), not before RCU synchronisation, of
- * course. Note that sta_info_destroy() must be protected by the RTNL.
+ * a call to sta_info_destroy().
*
* In all other cases, there is no concept of ownership on a STA entry,
* each structure is owned by the global hash table/list until it is
struct sk_buff *skb;
int i;
- ASSERT_RTNL();
might_sleep();
if (!sta)
mesh_plink_deactivate(sta);
#endif
- if (sta->key) {
- /*
- * NOTE: This will call synchronize_rcu() internally to
- * make sure no key references can be in use. We rely on
- * that when we take this branch to make sure nobody can
- * reference this STA struct any longer!
- */
- ieee80211_key_free(sta->key);
- WARN_ON(sta->key);
- } else {
- /*
- * Make sure that nobody can reference this STA struct
- * any longer.
- */
- synchronize_rcu();
- }
+ /*
+ * We have only unlinked the key, and actually destroying it
+ * may mean it is removed from hardware which requires that
+ * the key->sta pointer is still valid, so flush the key todo
+ * list here.
+ *
+ * ieee80211_key_todo() will synchronize_rcu() so after this
+ * nothing can reference this sta struct any more.
+ */
+ ieee80211_key_todo();
#ifdef CONFIG_MAC80211_MESH
if (ieee80211_vif_is_mesh(&sta->sdata->vif))
* NOTE: due to auto-freeing semantics this may only be done
* if the insertion is successful!
*/
- queue_work(local->hw.workqueue, &local->sta_debugfs_add);
+ schedule_work(&local->sta_debugfs_add);
#endif
if (ieee80211_vif_is_mesh(&sdata->vif))
spin_unlock_irqrestore(&sta->local->sta_lock, flags);
}
-/*
- * See comment in __sta_info_unlink,
- * caller must hold local->sta_lock.
- */
-static void __sta_info_pin(struct sta_info *sta)
-{
- WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
- sta->pin_status = STA_INFO_PIN_STAT_PINNED;
-}
-
-/*
- * See comment in __sta_info_unlink, returns sta if it
- * needs to be destroyed.
- */
-static struct sta_info *__sta_info_unpin(struct sta_info *sta)
-{
- struct sta_info *ret = NULL;
- unsigned long flags;
-
- spin_lock_irqsave(&sta->local->sta_lock, flags);
- WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
- sta->pin_status != STA_INFO_PIN_STAT_PINNED);
- if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
- ret = sta;
- sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
- spin_unlock_irqrestore(&sta->local->sta_lock, flags);
-
- return ret;
-}
-
-static void __sta_info_unlink(struct sta_info **sta)
+void __sta_info_unlink(struct sta_info **sta)
{
struct ieee80211_local *local = (*sta)->local;
struct ieee80211_sub_if_data *sdata = (*sta)->sdata;
return;
}
- /*
- * Also pull caller's reference if the STA is pinned by the
- * task that is adding the debugfs entries. In that case, we
- * leave the STA "to be freed".
- *
- * The rules are not trivial, but not too complex either:
- * (1) pin_status is only modified under the sta_lock
- * (2) sta_info_debugfs_add_work() will set the status
- * to PINNED when it found an item that needs a new
- * debugfs directory created. In that case, that item
- * must not be freed although all *RCU* users are done
- * with it. Hence, we tell the caller of _unlink()
- * that the item is already gone (as can happen when
- * two tasks try to unlink/destroy at the same time)
- * (3) We set the pin_status to DESTROY here when we
- * find such an item.
- * (4) sta_info_debugfs_add_work() will reset the pin_status
- * from PINNED to NORMAL when it is done with the item,
- * but will check for DESTROY before resetting it in
- * which case it will free the item.
- */
- if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
- (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
- *sta = NULL;
- return;
+ if ((*sta)->key) {
+ ieee80211_key_free((*sta)->key);
+ WARN_ON((*sta)->key);
}
list_del(&(*sta)->list);
printk(KERN_DEBUG "%s: Removed STA %s\n",
wiphy_name(local->hw.wiphy), print_mac(mbuf, (*sta)->addr));
#endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
+
+ /*
+ * Finally, pull caller's reference if the STA is pinned by the
+ * task that is adding the debugfs entries. In that case, we
+ * leave the STA "to be freed".
+ *
+ * The rules are not trivial, but not too complex either:
+ * (1) pin_status is only modified under the sta_lock
+ * (2) STAs may only be pinned under the RTNL so that
+ * sta_info_flush() is guaranteed to actually destroy
+ * all STAs that are active for a given interface, this
+ * is required for correctness because otherwise we
+ * could notify a driver that an interface is going
+ * away and only after that (!) notify it about a STA
+ * on that interface going away.
+ * (3) sta_info_debugfs_add_work() will set the status
+ * to PINNED when it found an item that needs a new
+ * debugfs directory created. In that case, that item
+ * must not be freed although all *RCU* users are done
+ * with it. Hence, we tell the caller of _unlink()
+ * that the item is already gone (as can happen when
+ * two tasks try to unlink/destroy at the same time)
+ * (4) We set the pin_status to DESTROY here when we
+ * find such an item.
+ * (5) sta_info_debugfs_add_work() will reset the pin_status
+ * from PINNED to NORMAL when it is done with the item,
+ * but will check for DESTROY before resetting it in
+ * which case it will free the item.
+ */
+ if ((*sta)->pin_status == STA_INFO_PIN_STAT_PINNED) {
+ (*sta)->pin_status = STA_INFO_PIN_STAT_DESTROY;
+ *sta = NULL;
+ return;
+ }
}
void sta_info_unlink(struct sta_info **sta)
}
#ifdef CONFIG_MAC80211_DEBUGFS
+/*
+ * See comment in __sta_info_unlink,
+ * caller must hold local->sta_lock.
+ */
+static void __sta_info_pin(struct sta_info *sta)
+{
+ WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_NORMAL);
+ sta->pin_status = STA_INFO_PIN_STAT_PINNED;
+}
+
+/*
+ * See comment in __sta_info_unlink, returns sta if it
+ * needs to be destroyed.
+ */
+static struct sta_info *__sta_info_unpin(struct sta_info *sta)
+{
+ struct sta_info *ret = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&sta->local->sta_lock, flags);
+ WARN_ON(sta->pin_status != STA_INFO_PIN_STAT_DESTROY &&
+ sta->pin_status != STA_INFO_PIN_STAT_PINNED);
+ if (sta->pin_status == STA_INFO_PIN_STAT_DESTROY)
+ ret = sta;
+ sta->pin_status = STA_INFO_PIN_STAT_NORMAL;
+ spin_unlock_irqrestore(&sta->local->sta_lock, flags);
+
+ return ret;
+}
+
static void sta_info_debugfs_add_work(struct work_struct *work)
{
struct ieee80211_local *local =
struct sta_info *sta, *tmp;
unsigned long flags;
+ /* We need to keep the RTNL across the whole pinned status. */
+ rtnl_lock();
while (1) {
sta = NULL;
rate_control_add_sta_debugfs(sta);
sta = __sta_info_unpin(sta);
- rtnl_lock();
sta_info_destroy(sta);
- rtnl_unlock();
}
+ rtnl_unlock();
}
#endif
-void __ieee80211_run_pending_flush(struct ieee80211_local *local)
+static void __ieee80211_run_pending_flush(struct ieee80211_local *local)
{
struct sta_info *sta;
unsigned long flags;
{
del_timer(&local->sta_cleanup);
cancel_work_sync(&local->sta_flush_work);
+#ifdef CONFIG_MAC80211_DEBUGFS
+ /*
+ * Make sure the debugfs adding work isn't pending after this
+ * because we're about to be destroyed. It doesn't matter
+ * whether it ran or not since we're going to flush all STAs
+ * anyway.
+ */
+ cancel_work_sync(&local->sta_debugfs_add);
+#endif
rtnl_lock();
sta_info_flush(local, NULL);
projects / linux-2.6-omap-h63xx.git / blobdiff