From 4136c4224ccf1907d309e1cdfaefef9da97dbc5e Mon Sep 17 00:00:00 2001 From: Stanislaw Gruszka Date: Wed, 6 Oct 2010 11:22:10 +0200 Subject: mac80211: assure we also cancel deferred scan request This is partial revert and fix for commit 85f72bc839705294b32b6c16b491c0422f0a71b3 "mac80211: only cancel software-based scans on suspend" When cfg80211 request the scan and mac80211 perform some management work, we defer the scan request. We do not canceling such requests when calling ieee80211_scan_cancel(), because of SCAN_SW_SCANNING bit check just before the call. So fix that problem. Another problem, which commit 85f72bc839705294b32b6c16b491c0422f0a71b3 tries to solve, is we can not cancel HW scan. Hence patch make ieee80211_scan_cancel() ignore HW scan (see code comments). Keeping local->mtx lock assures that the deferred scan will not become "working" HW scan. Signed-off-by: Stanislaw Gruszka Acked-by: Johannes Berg Signed-off-by: John W. Linville --- net/mac80211/scan.c | 35 +++++++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 10 deletions(-) (limited to 'net/mac80211/scan.c') diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index 6964a459817..4dbef714d94 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -793,24 +793,39 @@ int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata, return ret; } +/* + * Only call this function when a scan can't be queued -- under RTNL. + */ void ieee80211_scan_cancel(struct ieee80211_local *local) { - bool abortscan; - bool finish = false; - - cancel_delayed_work_sync(&local->scan_work); + bool abortscan, finish; /* - * Only call this function when a scan can't be - * queued -- mostly at suspend under RTNL. + * We are only canceling software scan, or deferred scan that was not + * yet really started (see __ieee80211_start_scan ). + * + * Regarding hardware scan: + * - we can not call __ieee80211_scan_completed() as when + * SCAN_HW_SCANNING bit is set this function change + * local->hw_scan_req to operate on 5G band, what race with + * driver which can use local->hw_scan_req + * + * - we can not cancel scan_work since driver can schedule it + * by ieee80211_scan_completed(..., true) to finish scan + * + * Hence low lever driver is responsible for canceling HW scan. */ + mutex_lock(&local->mtx); - abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) || - (!local->scanning && local->scan_req); + abortscan = local->scan_req && !test_bit(SCAN_HW_SCANNING, &local->scanning); if (abortscan) finish = __ieee80211_scan_completed(&local->hw, true, false); mutex_unlock(&local->mtx); - if (finish) - __ieee80211_scan_completed_finish(&local->hw, false); + if (abortscan) { + /* The scan is canceled, but stop work from being pending */ + cancel_delayed_work_sync(&local->scan_work); + if (finish) + __ieee80211_scan_completed_finish(&local->hw, false); + } } -- cgit v1.2.3-70-g09d2