Messages in this thread Patch in this message | | | Date | Fri, 06 Aug 2010 12:20:01 -0700 | From | Greg KH <> | Subject | [20/36] iwlwifi: fix scan abort |
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2.6.34-stable review patch. If anyone has any objections, please let us know.
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From: Stanislaw Gruszka <sgruszka@redhat.com>
commit d28232b461b8d54b09e59325dbac8b0913ce2049 upstream.
Fix possible double priv->mutex lock introduced by commit a69b03e941abae00380fc6bc1877fb797a1b31e6 "iwlwifi: cancel scan watchdog in iwl_bg_abort_scan" . We can not call cancel_delayed_work_sync(&priv->scan_check) with priv->mutex locked because workqueue function iwl_bg_scan_check() take that lock internally.
We do not need to synchronize when canceling priv->scan_check work. We can avoid races (sending double abort command or send no command at all) using STATUS_SCAN_ABORT bit. Moreover current iwl_bg_scan_check() code seems to be broken, as we should not send abort commands when currently aborting.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/net/wireless/iwlwifi/iwl-scan.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)
--- a/drivers/net/wireless/iwlwifi/iwl-scan.c +++ b/drivers/net/wireless/iwlwifi/iwl-scan.c @@ -607,11 +607,10 @@ void iwl_bg_scan_check(struct work_struc return; mutex_lock(&priv->mutex); - if (test_bit(STATUS_SCANNING, &priv->status) || - test_bit(STATUS_SCAN_ABORTING, &priv->status)) { - IWL_DEBUG_SCAN(priv, "Scan completion watchdog resetting " - "adapter (%dms)\n", - jiffies_to_msecs(IWL_SCAN_CHECK_WATCHDOG)); + if (test_bit(STATUS_SCANNING, &priv->status) && + !test_bit(STATUS_SCAN_ABORTING, &priv->status)) { + IWL_DEBUG_SCAN(priv, "Scan completion watchdog (%dms)\n", + jiffies_to_msecs(IWL_SCAN_CHECK_WATCHDOG)); if (!test_bit(STATUS_EXIT_PENDING, &priv->status)) iwl_send_scan_abort(priv); @@ -950,12 +949,11 @@ void iwl_bg_abort_scan(struct work_struc !test_bit(STATUS_GEO_CONFIGURED, &priv->status)) return; - mutex_lock(&priv->mutex); - - cancel_delayed_work_sync(&priv->scan_check); - set_bit(STATUS_SCAN_ABORTING, &priv->status); - iwl_send_scan_abort(priv); + cancel_delayed_work(&priv->scan_check); + mutex_lock(&priv->mutex); + if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) + iwl_send_scan_abort(priv); mutex_unlock(&priv->mutex); } EXPORT_SYMBOL(iwl_bg_abort_scan);
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