Re: Latest wireless-testing has broken scan locking.

[Johannes Berg <johannes@sipsolutions.net>]

On Wed, 2010-10-06 at 21:13 -0700, Ben Greear wrote:
> Unless I really screwed up a merge in a strange way, the
> ieee80211_scan_work is broken.
> 
> It calls mutex_unlock(&local->mtx) too many times when it hits
> this code:
> 
> 		case SCAN_DECISION:
> 			/* if no more bands/channels left, complete scan */
> 			if (local->scan_channel_idx >= local->scan_req->n_channels) {
> 				aborted = false;
> 				goto out_complete;
> 			}

So much for trusting Stanislaw :-( I can reproduce this in hwsim.
Stanislaw, did you ever test software scan at all?

Below patch fixes this.

johannes

---
 net/mac80211/scan.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- wireless-testing.orig/net/mac80211/scan.c	2010-10-07 10:27:37.000000000 +0200
+++ wireless-testing/net/mac80211/scan.c	2010-10-07 10:31:19.000000000 +0200
@@ -693,8 +693,6 @@ void ieee80211_scan_work(struct work_str
 		goto out_complete;
 	}
 
-	mutex_unlock(&local->mtx);
-
 	/*
 	 * as long as no delay is required advance immediately
 	 * without scheduling a new work
@@ -725,6 +723,7 @@ void ieee80211_scan_work(struct work_str
 	} while (next_delay == 0);
 
 	ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
+	mutex_unlock(&local->mtx);
 	return;
 
 out_complete: