Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754738AbZGJMhJ (ORCPT ); Fri, 10 Jul 2009 08:37:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750983AbZGJMg4 (ORCPT ); Fri, 10 Jul 2009 08:36:56 -0400 Received: from smtp.nokia.com ([192.100.122.230]:36653 "EHLO mgw-mx03.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750924AbZGJMgz (ORCPT ); Fri, 10 Jul 2009 08:36:55 -0400 From: Adrian Hunter To: Pierre Ossman Cc: Jarkko Lavinen , Denis Karpov , Adrian Hunter , lkml , linux-omap Mailing List Date: Fri, 10 Jul 2009 15:40:19 +0300 Message-Id: <20090710124019.1262.83078.sendpatchset@ahunter-tower> In-Reply-To: <20090710124004.1262.10422.sendpatchset@ahunter-tower> References: <20090710124004.1262.10422.sendpatchset@ahunter-tower> Subject: [PATCH 2/32] mmc: allow host claim / release nesting X-OriginalArrivalTime: 10 Jul 2009 12:36:45.0847 (UTC) FILETIME=[16222A70:01CA015B] X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3877 Lines: 126 >From 2d65438fce412a63f09f90fb9af1049c775cbd70 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Mon, 27 Apr 2009 13:38:42 +0300 Subject: [PATCH] mmc: allow host claim / release nesting This change allows the MMC host to be claimed in situations where the host may or may not have already been claimed. Also 'mmc_try_claim_host()' is now exported. Signed-off-by: Adrian Hunter --- drivers/mmc/core/core.c | 34 +++++++++++++++++++++++++--------- include/linux/mmc/core.h | 1 + include/linux/mmc/host.h | 2 ++ 3 files changed, 28 insertions(+), 9 deletions(-) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 41fd127..b262dc6 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -458,16 +458,18 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort) while (1) { set_current_state(TASK_UNINTERRUPTIBLE); stop = abort ? atomic_read(abort) : 0; - if (stop || !host->claimed) + if (stop || !host->claimed || host->claimer == current) break; spin_unlock_irqrestore(&host->lock, flags); schedule(); spin_lock_irqsave(&host->lock, flags); } set_current_state(TASK_RUNNING); - if (!stop) + if (!stop) { host->claimed = 1; - else + host->claimer = current; + host->claim_cnt += 1; + } else wake_up(&host->wq); spin_unlock_irqrestore(&host->lock, flags); remove_wait_queue(&host->wq, &wait); @@ -478,29 +480,43 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t *abort) EXPORT_SYMBOL(__mmc_claim_host); -static int mmc_try_claim_host(struct mmc_host *host) +/** + * mmc_try_claim_host - try exclusively to claim a host + * @host: mmc host to claim + * + * Returns %1 if the host is claimed, %0 otherwise. + */ +int mmc_try_claim_host(struct mmc_host *host) { int claimed_host = 0; unsigned long flags; spin_lock_irqsave(&host->lock, flags); - if (!host->claimed) { + if (!host->claimed || host->claimer == current) { host->claimed = 1; + host->claimer = current; + host->claim_cnt += 1; claimed_host = 1; } spin_unlock_irqrestore(&host->lock, flags); return claimed_host; } +EXPORT_SYMBOL(mmc_try_claim_host); static void mmc_do_release_host(struct mmc_host *host) { unsigned long flags; spin_lock_irqsave(&host->lock, flags); - host->claimed = 0; - spin_unlock_irqrestore(&host->lock, flags); - - wake_up(&host->wq); + if (--host->claim_cnt) { + /* Release for nested claim */ + spin_unlock_irqrestore(&host->lock, flags); + } else { + host->claimed = 0; + host->claimer = NULL; + spin_unlock_irqrestore(&host->lock, flags); + wake_up(&host->wq); + } } void mmc_host_deeper_disable(struct work_struct *work) diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h index 7ac8b50..e4898e9 100644 --- a/include/linux/mmc/core.h +++ b/include/linux/mmc/core.h @@ -139,6 +139,7 @@ extern unsigned int mmc_align_data_size(struct mmc_card *, unsigned int); extern int __mmc_claim_host(struct mmc_host *host, atomic_t *abort); extern void mmc_release_host(struct mmc_host *host); +extern int mmc_try_claim_host(struct mmc_host *host); /** * mmc_claim_host - exclusively claim a host diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 583c068..9cc5be9 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -182,6 +182,8 @@ struct mmc_host { struct mmc_card *card; /* device attached to this host */ wait_queue_head_t wq; + struct task_struct *claimer; /* task that has host claimed */ + int claim_cnt; /* "claim" nesting count */ struct delayed_work detect; -- 1.5.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/