We are taking local->mtx inside __ieee80211_scan_completed(), but just
before call to that function we drop the lock. Dropping/taking lock is not
good, because can lead to hard to understand race conditions.
Patch split scan_completed() code into two functions, first must be called
with local->mtx taken and second without it.
Signed-off-by: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
---
net/mac80211/scan.c | 85 +++++++++++++++++++++++++++------------------------
1 files changed, 45 insertions(+), 40 deletions(-)
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index e9ab896..44deb05 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -250,12 +250,12 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
return true;
}
-static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
+static bool __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
+ bool was_hw_scan)
{
struct ieee80211_local *local = hw_to_local(hw);
- bool was_hw_scan;
- mutex_lock(&local->mtx);
+ lockdep_assert_held(&local->mtx);
/*
* It's ok to abort a not-yet-running scan (that
@@ -266,17 +266,13 @@ static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
if (WARN_ON(!local->scanning && !aborted))
aborted = true;
- if (WARN_ON(!local->scan_req)) {
- mutex_unlock(&local->mtx);
- return;
- }
+ if (WARN_ON(!local->scan_req))
+ return false;
- was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
ieee80211_queue_delayed_work(&local->hw,
&local->scan_work, 0);
- mutex_unlock(&local->mtx);
- return;
+ return false;
}
kfree(local->hw_scan_req);
@@ -290,23 +286,25 @@ static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
local->scanning = 0;
local->scan_channel = NULL;
- /* we only have to protect scan_req and hw/sw scan */
- mutex_unlock(&local->mtx);
-
- ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
- if (was_hw_scan)
- goto done;
-
- ieee80211_configure_filter(local);
+ return true;
+}
- drv_sw_scan_complete(local);
+static void __ieee80211_scan_completed_finish(struct ieee80211_hw *hw,
+ bool was_hw_scan)
+{
+ struct ieee80211_local *local = hw_to_local(hw);
- ieee80211_offchannel_return(local, true);
+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+ if (!was_hw_scan) {
+ ieee80211_configure_filter(local);
+ drv_sw_scan_complete(local);
+ ieee80211_offchannel_return(local, true);
+ }
- done:
mutex_lock(&local->mtx);
ieee80211_recalc_idle(local);
mutex_unlock(&local->mtx);
+
ieee80211_mlme_notify_scan_completed(local);
ieee80211_ibss_notify_scan_completed(local);
ieee80211_mesh_notify_scan_completed(local);
@@ -367,6 +365,8 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
struct ieee80211_local *local = sdata->local;
int rc;
+ lockdep_assert_held(&local->mtx);
+
if (local->scan_req)
return -EBUSY;
@@ -432,7 +432,6 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
local->scan_req = NULL;
local->scan_sdata = NULL;
}
-
return rc;
}
@@ -448,8 +447,8 @@ ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
}
-static int ieee80211_scan_state_decision(struct ieee80211_local *local,
- unsigned long *next_delay)
+static void ieee80211_scan_state_decision(struct ieee80211_local *local,
+ unsigned long *next_delay)
{
bool associated = false;
bool tx_empty = true;
@@ -459,12 +458,6 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata;
struct ieee80211_channel *next_chan;
- /* if no more bands/channels left, complete scan and advance to the idle state */
- if (local->scan_channel_idx >= local->scan_req->n_channels) {
- __ieee80211_scan_completed(&local->hw, false);
- return 1;
- }
-
/*
* check if at least one STA interface is associated,
* check if at least one STA interface has pending tx frames
@@ -536,7 +529,6 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local,
}
*next_delay = 0;
- return 0;
}
static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
@@ -654,6 +646,7 @@ void ieee80211_scan_work(struct work_struct *work)
unsigned long next_delay = 0;
int rc = 1;
bool aborted = true;
+ bool finish, hw_scan;
mutex_lock(&local->mtx);
@@ -697,8 +690,12 @@ void ieee80211_scan_work(struct work_struct *work)
do {
switch (local->next_scan_state) {
case SCAN_DECISION:
- if (ieee80211_scan_state_decision(local, &next_delay))
- return;
+ /* if no more bands/channels left, complete scan */
+ if (local->scan_channel_idx >= local->scan_req->n_channels) {
+ aborted = false;
+ goto out_complete;
+ }
+ ieee80211_scan_state_decision(local, &next_delay);
break;
case SCAN_SET_CHANNEL:
ieee80211_scan_state_set_channel(local, &next_delay);
@@ -719,9 +716,16 @@ void ieee80211_scan_work(struct work_struct *work)
return;
out_complete:
+ finish = false;
+ if (rc) {
+ hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
+ finish = __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
+ }
+
mutex_unlock(&local->mtx);
- if (rc)
- __ieee80211_scan_completed(&local->hw, true);
+
+ if (finish)
+ __ieee80211_scan_completed_finish(&local->hw, hw_scan);
}
int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
@@ -785,7 +789,7 @@ int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
void ieee80211_scan_cancel(struct ieee80211_local *local)
{
- bool abortscan;
+ bool finish = false;
cancel_delayed_work_sync(&local->scan_work);
@@ -794,10 +798,11 @@ void ieee80211_scan_cancel(struct ieee80211_local *local)
* queued -- mostly at suspend under RTNL.
*/
mutex_lock(&local->mtx);
- abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
- (!local->scanning && local->scan_req);
+ if (test_bit(SCAN_SW_SCANNING, &local->scanning) ||
+ (!local->scanning && local->scan_req))
+ finish = __ieee80211_scan_completed(&local->hw, true, false);
mutex_unlock(&local->mtx);
- if (abortscan)
- __ieee80211_scan_completed(&local->hw, true);
+ if (finish)
+ __ieee80211_scan_completed_finish(&local->hw, false);
}
--
1.7.1
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