From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752052Ab2LVB55 (ORCPT ); Fri, 21 Dec 2012 20:57:57 -0500 Received: from mail-ie0-f172.google.com ([209.85.223.172]:43419 "EHLO mail-ie0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750832Ab2LVB5y (ORCPT ); Fri, 21 Dec 2012 20:57:54 -0500 From: Tejun Heo To: linux-kernel@vger.kernel.org Cc: Tejun Heo , Anton Vorontsov , David Woodhouse , Donggeun Kim , MyungJoo Ham Subject: [PATCH 01/25] charger_manager: don't use [delayed_]work_pending() Date: Fri, 21 Dec 2012 17:56:51 -0800 Message-Id: <1356141435-17340-2-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.8.0.2 In-Reply-To: <1356141435-17340-1-git-send-email-tj@kernel.org> References: <1356141435-17340-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There's no need to test whether a (delayed) work item in pending before queueing, flushing or cancelling it. Most uses are unnecessary and quite a few of them are buggy. Remove unnecessary pending tests and rewrite _setup_polling() so that it uses mod_delayed_work() if the next polling interval is sooner than currently scheduled. queue_delayed_work() is used otherwise. Only compile tested. I noticed that two work items - setup_polling and cm_monitor_work - schedule each other. It's a very unusual construct and I'm fairly sure it's racy. You can't break such circular dependency by calling cancel on each. I strongly recommend revising the mechanism. Signed-off-by: Tejun Heo Cc: Anton Vorontsov Cc: David Woodhouse Cc: Donggeun Kim Cc: MyungJoo Ham --- Please let me know how this patch should be routed. I can take it through the workqueue tree if necessary. Thanks. drivers/power/charger-manager.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/drivers/power/charger-manager.c b/drivers/power/charger-manager.c index adb3a4b..9fd9776 100644 --- a/drivers/power/charger-manager.c +++ b/drivers/power/charger-manager.c @@ -675,15 +675,21 @@ static void _setup_polling(struct work_struct *work) WARN(cm_wq == NULL, "charger-manager: workqueue not initialized" ". try it later. %s\n", __func__); + /* + * Use mod_delayed_work() iff the next polling interval should + * occur before the currently scheduled one. If @cm_monitor_work + * isn't active, the end result is the same, so no need to worry + * about stale @next_polling. + */ _next_polling = jiffies + polling_jiffy; - if (!delayed_work_pending(&cm_monitor_work) || - (delayed_work_pending(&cm_monitor_work) && - time_after(next_polling, _next_polling))) { - next_polling = jiffies + polling_jiffy; + if (time_before(_next_polling, next_polling)) { mod_delayed_work(cm_wq, &cm_monitor_work, polling_jiffy); + next_polling = _next_polling; + } else { + if (queue_delayed_work(cm_wq, &cm_monitor_work, polling_jiffy)) + next_polling = _next_polling; } - out: mutex_unlock(&cm_list_mtx); } @@ -757,8 +763,7 @@ static void misc_event_handler(struct charger_manager *cm, if (cm_suspended) device_set_wakeup_capable(cm->dev, true); - if (!delayed_work_pending(&cm_monitor_work) && - is_polling_required(cm) && cm->desc->polling_interval_ms) + if (is_polling_required(cm) && cm->desc->polling_interval_ms) schedule_work(&setup_polling); uevent_notify(cm, default_event_names[type]); } @@ -1176,8 +1181,7 @@ static int charger_extcon_notifier(struct notifier_block *self, * when charger cable is attached. */ if (cable->attached && is_polling_required(cable->cm)) { - if (work_pending(&setup_polling)) - cancel_work_sync(&setup_polling); + cancel_work_sync(&setup_polling); schedule_work(&setup_polling); } @@ -1667,10 +1671,8 @@ static int charger_manager_remove(struct platform_device *pdev) list_del(&cm->entry); mutex_unlock(&cm_list_mtx); - if (work_pending(&setup_polling)) - cancel_work_sync(&setup_polling); - if (delayed_work_pending(&cm_monitor_work)) - cancel_delayed_work_sync(&cm_monitor_work); + cancel_work_sync(&setup_polling); + cancel_delayed_work_sync(&cm_monitor_work); for (i = 0 ; i < desc->num_charger_regulators ; i++) { struct charger_regulator *charger @@ -1739,8 +1741,7 @@ static int cm_suspend_prepare(struct device *dev) cm_suspended = true; } - if (delayed_work_pending(&cm->fullbatt_vchk_work)) - cancel_delayed_work(&cm->fullbatt_vchk_work); + cancel_delayed_work(&cm->fullbatt_vchk_work); cm->status_save_ext_pwr_inserted = is_ext_pwr_online(cm); cm->status_save_batt = is_batt_present(cm); -- 1.8.0.2