From patchwork Sun Jul 31 17:48:26 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rafael Wysocki X-Patchwork-Id: 1023932 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.4) with ESMTP id p6VHr3ml006138 for ; Sun, 31 Jul 2011 17:53:03 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752437Ab1GaRwx (ORCPT ); Sun, 31 Jul 2011 13:52:53 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:36729 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751818Ab1GaRww (ORCPT ); Sun, 31 Jul 2011 13:52:52 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by ogre.sisk.pl (Postfix) with ESMTP id EE7051B6CCF; Sun, 31 Jul 2011 19:18:54 +0200 (CEST) Received: from ogre.sisk.pl ([127.0.0.1]) by localhost (ogre.sisk.pl [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 28084-05; Sun, 31 Jul 2011 19:18:22 +0200 (CEST) Received: from ferrari.rjw.lan (220-bem-13.acn.waw.pl [82.210.184.220]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ogre.sisk.pl (Postfix) with ESMTP id 865C11B6B9C; Sun, 31 Jul 2011 19:18:22 +0200 (CEST) From: "Rafael J. Wysocki" To: Linux PM mailing list Subject: [PATCH 3/9] PM / Domains: Do not take parent locks to modify subdomain counters Date: Sun, 31 Jul 2011 19:48:26 +0200 User-Agent: KMail/1.13.6 (Linux/3.0.0+; KDE/4.6.0; x86_64; ; ) Cc: LKML , Magnus Damm , linux-sh@vger.kernel.org References: <201107311946.06654.rjw@sisk.pl> In-Reply-To: <201107311946.06654.rjw@sisk.pl> MIME-Version: 1.0 Message-Id: <201107311948.26609.rjw@sisk.pl> X-Virus-Scanned: amavisd-new at ogre.sisk.pl using MkS_Vir for Linux Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter1.kernel.org [140.211.167.41]); Sun, 31 Jul 2011 17:53:04 +0000 (UTC) From: Rafael J. Wysocki After the subdomain counter in struct generic_pm_domain has been changed into an atomic_t field, it is possible to modify pm_genpd_poweron() and pm_genpd_poweroff() so that they don't take the parents locks. This requires pm_genpd_poweron() to increment the parent's subdomain counter before calling itself recursively for the parent and to decrement it if an error is to be returned. Signed-off-by: Rafael J. Wysocki --- drivers/base/power/domain.c | 70 +++++++++++++++++++------------------------- 1 file changed, 31 insertions(+), 39 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: linux-2.6/drivers/base/power/domain.c =================================================================== --- linux-2.6.orig/drivers/base/power/domain.c +++ linux-2.6/drivers/base/power/domain.c @@ -93,12 +93,7 @@ int pm_genpd_poweron(struct generic_pm_d int ret = 0; start: - if (parent) { - genpd_acquire_lock(parent); - mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING); - } else { - mutex_lock(&genpd->lock); - } + mutex_lock(&genpd->lock); if (genpd->status == GPD_STATE_ACTIVE || (genpd->prepared_count > 0 && genpd->suspend_power_off)) @@ -109,31 +104,33 @@ int pm_genpd_poweron(struct generic_pm_d goto out; } - if (parent && parent->status != GPD_STATE_ACTIVE) { + if (parent) { + genpd_sd_counter_inc(parent); + mutex_unlock(&genpd->lock); - genpd_release_lock(parent); ret = pm_genpd_poweron(parent); - if (ret) + if (ret) { + genpd_sd_counter_dec(parent); return ret; + } + parent = NULL; goto start; } - if (genpd->power_on) { + if (genpd->power_on) ret = genpd->power_on(genpd); - if (ret) - goto out; - } - genpd_set_active(genpd); - if (parent) - genpd_sd_counter_inc(parent); + if (ret) { + if (genpd->parent) + genpd_sd_counter_dec(genpd->parent); + } else { + genpd_set_active(genpd); + } out: mutex_unlock(&genpd->lock); - if (parent) - genpd_release_lock(parent); return ret; } @@ -293,7 +290,8 @@ static int pm_genpd_poweroff(struct gene genpd->poweroff_task = current; list_for_each_entry_reverse(dle, &genpd->dev_list, node) { - ret = __pm_genpd_save_device(dle, genpd); + ret = atomic_read(&genpd->sd_count) == 0 ? + __pm_genpd_save_device(dle, genpd) : -EBUSY; if (ret) { genpd_set_active(genpd); goto out; @@ -308,38 +306,32 @@ static int pm_genpd_poweroff(struct gene } } - parent = genpd->parent; - if (parent) { - mutex_unlock(&genpd->lock); - - genpd_acquire_lock(parent); - mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING); - - if (genpd_abort_poweroff(genpd)) { - genpd_release_lock(parent); + if (genpd->power_off) { + if (atomic_read(&genpd->sd_count) > 0) { + ret = -EBUSY; goto out; } - } - if (genpd->power_off) { + /* + * If sd_count > 0 at this point, one of the children hasn't + * managed to call pm_genpd_poweron() for the parent yet after + * incrementing it. In that case pm_genpd_poweron() will wait + * for us to drop the lock, so we can call .power_off() and let + * the pm_genpd_poweron() restore power for us (this shouldn't + * happen very often). + */ ret = genpd->power_off(genpd); if (ret == -EBUSY) { genpd_set_active(genpd); - if (parent) - genpd_release_lock(parent); - goto out; } } genpd->status = GPD_STATE_POWER_OFF; - if (parent) { - if (genpd_sd_counter_dec(parent)) - genpd_queue_power_off_work(parent); - - genpd_release_lock(parent); - } + parent = genpd->parent; + if (parent && genpd_sd_counter_dec(parent)) + genpd_queue_power_off_work(parent); out: genpd->poweroff_task = NULL;