Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753471AbZG1KmM (ORCPT ); Tue, 28 Jul 2009 06:42:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753477AbZG1KmL (ORCPT ); Tue, 28 Jul 2009 06:42:11 -0400 Received: from smtp.nokia.com ([192.100.122.230]:32595 "EHLO mgw-mx03.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753237AbZG1KmG (ORCPT ); Tue, 28 Jul 2009 06:42:06 -0400 From: Adrian Hunter To: Andrew Morton Cc: Jarkko Lavinen , Adrian Hunter , linux-omap Mailing List , Pierre Ossman , Denis Karpov , Matt Fleming , lkml Date: Tue, 28 Jul 2009 13:41:47 +0300 Message-Id: <20090728104147.2371.8059.sendpatchset@ahunter-laptop> In-Reply-To: <20090728103834.2371.65809.sendpatchset@ahunter-laptop> References: <20090728103834.2371.65809.sendpatchset@ahunter-laptop> Subject: [PATCH V2 26/32] omap_hsmmc: prevent races with irq handler X-OriginalArrivalTime: 28 Jul 2009 10:41:15.0779 (UTC) FILETIME=[EEED3530:01CA0F6F] X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3610 Lines: 111 >From 4252559187e96877a2a7ab5a5b0d0631aa51c7d2 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Sat, 16 May 2009 10:32:34 +0300 Subject: [PATCH] omap_hsmmc: prevent races with irq handler If an unexpected interrupt occurs while preparing the next request, an oops can occur. For example, a new request is setting up DMA for data transfer so host->data is not NULL. An unexpected transfer complete (TC) interrupt comes along and the interrupt handler sets host->data to NULL. Oops! Prevent that by adding a spinlock. Signed-off-by: Adrian Hunter --- drivers/mmc/host/omap_hsmmc.c | 25 +++++++++++++++++++++++++ 1 files changed, 25 insertions(+), 0 deletions(-) diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index 5121277..5213d87 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -146,6 +146,8 @@ struct mmc_omap_host { struct work_struct mmc_carddetect_work; void __iomem *base; resource_size_t mapbase; + spinlock_t irq_lock; /* Prevent races with irq handler */ + unsigned long flags; unsigned int id; unsigned int dma_len; unsigned int dma_sg_idx; @@ -452,6 +454,14 @@ mmc_omap_start_command(struct mmc_omap_host *host, struct mmc_command *cmd, if (host->use_dma) cmdreg |= DMA_EN; + /* + * In an interrupt context (i.e. STOP command), the spinlock is unlocked + * by the interrupt handler, otherwise (i.e. for a new request) it is + * unlocked here. + */ + if (!in_interrupt()) + spin_unlock_irqrestore(&host->irq_lock, host->flags); + OMAP_HSMMC_WRITE(host->base, ARG, cmd->arg); OMAP_HSMMC_WRITE(host->base, CMD, cmdreg); } @@ -614,11 +624,14 @@ static irqreturn_t mmc_omap_irq(int irq, void *dev_id) struct mmc_data *data; int end_cmd = 0, end_trans = 0, status; + spin_lock(&host->irq_lock); + if (host->mrq == NULL) { OMAP_HSMMC_WRITE(host->base, STAT, OMAP_HSMMC_READ(host->base, STAT)); /* Flush posted write */ OMAP_HSMMC_READ(host->base, STAT); + spin_unlock(&host->irq_lock); return IRQ_HANDLED; } @@ -683,6 +696,8 @@ static irqreturn_t mmc_omap_irq(int irq, void *dev_id) if ((end_trans || (status & TC)) && host->mrq) mmc_omap_xfer_done(host, data); + spin_unlock(&host->irq_lock); + return IRQ_HANDLED; } @@ -1011,6 +1026,13 @@ static void omap_mmc_request(struct mmc_host *mmc, struct mmc_request *req) struct mmc_omap_host *host = mmc_priv(mmc); int err; + /* + * Prevent races with the interrupt handler because of unexpected + * interrupts, but not if we are already in interrupt context i.e. + * retries. + */ + if (!in_interrupt()) + spin_lock_irqsave(&host->irq_lock, host->flags); WARN_ON(host->mrq != NULL); host->mrq = req; err = mmc_omap_prepare_data(host, req); @@ -1019,6 +1041,8 @@ static void omap_mmc_request(struct mmc_host *mmc, struct mmc_request *req) if (req->data) req->data->error = err; host->mrq = NULL; + if (!in_interrupt()) + spin_unlock_irqrestore(&host->irq_lock, host->flags); mmc_request_done(mmc, req); return; } @@ -1573,6 +1597,7 @@ static int __init omap_mmc_probe(struct platform_device *pdev) mmc->f_max = 52000000; sema_init(&host->sem, 1); + spin_lock_init(&host->irq_lock); host->iclk = clk_get(&pdev->dev, "ick"); if (IS_ERR(host->iclk)) { -- 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/