From patchwork Mon Sep 22 15:57:42 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Warren X-Patchwork-Id: 4948801 Return-Path: X-Original-To: patchwork-linux-mmc@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 131599F2BB for ; Mon, 22 Sep 2014 15:57:29 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EFCF82021A for ; Mon, 22 Sep 2014 15:57:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 60093201FA for ; Mon, 22 Sep 2014 15:57:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753934AbaIVP5Z (ORCPT ); Mon, 22 Sep 2014 11:57:25 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:56700 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753698AbaIVP5Y (ORCPT ); Mon, 22 Sep 2014 11:57:24 -0400 Received: from severn.wwwdotorg.org (unknown [192.168.65.5]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by avon.wwwdotorg.org (Postfix) with ESMTPS id 13971644E; Mon, 22 Sep 2014 09:57:24 -0600 (MDT) Received: from swarren-lx1.nvidia.com (localhost [127.0.0.1]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by severn.wwwdotorg.org (Postfix) with ESMTPSA id 375ADE460D; Mon, 22 Sep 2014 09:57:22 -0600 (MDT) From: Stephen Warren To: Chris Ball , Ulf Hansson Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Stephen Warren , Russell King , Adrian Hunter , Alexandre Courbot , Linus Walleij Subject: [PATCH] mmc: don't request CD IRQ until mmc_start_host() Date: Mon, 22 Sep 2014 09:57:42 -0600 Message-Id: <1411401462-1509-1-git-send-email-swarren@wwwdotorg.org> X-Mailer: git-send-email 1.9.1 X-NVConfidentiality: public X-Virus-Scanned: clamav-milter 0.97.8 at avon.wwwdotorg.org X-Virus-Status: Clean Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Stephen Warren As soon as the CD IRQ is requested, it can trigger, since it's an externally controlled event. If it does, delayed_work host->detect will be scheduled. Many host controller probe()s are roughly structured as: *_probe() { host = sdhci_pltfm_init(); mmc_of_parse(host->mmc); rc = sdhci_add_host(host); if (rc) { sdhci_pltfm_free(); return rc; } In 3.17, CD IRQs can are enabled quite early via *_probe() -> mmc_of_parse() -> mmc_gpio_request_cd() -> mmc_gpiod_request_cd_irq(). Note that in linux-next, mmc_of_parse() calls mmc_gpio*d*_request_cd() rather than mmc_gpio_request_cd(), and mmc_gpio*d*_request_cd() doesn't call mmc_gpiod_request_cd_irq(). However, this issue still exists if mmc_gpio_request_cd() is called directly before mmc_start_host(). sdhci_add_host() may fail part way through (e.g. due to deferred probe for a vmmc regulator), and sdhci_pltfm_free() does nothing to unrequest the CD IRQ nor cancel the delayed_work. sdhci_pltfm_free() is coded to assume that if sdhci_add_host() failed, then the delayed_work cannot (or should not) have been triggered. This can lead to the following with CONFIG_DEBUG_OBJECTS_* enabled, when kfree(host) is eventually called inside sdhci_pltfm_free(): WARNING: CPU: 2 PID: 6 at lib/debugobjects.c:263 debug_print_object+0x8c/0xb4() ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x18 The object being complained about is host->detect. There's no need to request the CD IRQ so early; mmc_start_host() already requests it. For most SDHCI hosts at least, the typical call path that does this is: *_probe() -> sdhci_add_host() -> mmc_add_host() -> mmc_start_host(). Therefore, remove the call to mmc_gpiod_request_cd_irq() from mmc_gpio_request_cd(). This also matches mmc_gpio*d*_request_cd(), which already doesn't call mmc_gpiod_request_cd_irq(). However, some host controller drivers call mmc_gpio_request_cd() after mmc_start_host() has already been called, and assume that this will also call mmc_gpiod_request_cd_irq(). Update those drivers to explicitly call mmc_gpiod_request_cd_irq() themselves. Ideally, these drivers should be modified to move their call to mmc_gpio_request_cd() before their call to mmc_add_host(). However that's too large a change for stable. This solves the problem (eliminates the kernel error message above), since it guarantees that the IRQ can't trigger before mmc_start_host() is called. The critical point here is that once sdhci_add_host() calls mmc_add_host() -> mmc_start_host(), sdhci_add_host() is coded not to fail. In other words, if there's a chance that mmc_start_host() may have been called, and CD IRQs triggered, and the delayed_work scheduled, sdhci_add_host() won't fail, and so cleanup is no longer via sdhci_pltfm_free() (which doesn't free the IRQ or cancel the work queue) but instead must be via sdhci_remove_host(), which calls mmc_remove_host() -> mmc_stop_host(), which does free the IRQ and cancel the work queue. CC: Russell King Cc: Adrian Hunter Cc: Alexandre Courbot Cc: Linus Walleij Signed-off-by: Stephen Warren Acked-by: Adrian Hunter --- Note: This is a patch for v3.17 (and perhaps earlier); linux-next doesn't have this problem due to other code re-structing. However, I think those patches are too large to backport. v3: Explicitly call mmc_gpiod_request_cd_irq() from drivers that call mmc_gpio_request_cd() after calling mmc_add_host(), rather than modifying the function signature of mmc_gpio_request_cd(). v2: Rather than completely removing mmc_gpio_request_cd()'s call to mmc_gpiod_request_cd_irq(), make the call conditional. --- drivers/mmc/core/slot-gpio.c | 2 -- drivers/mmc/host/mmc_spi.c | 1 + drivers/mmc/host/sdhci-sirf.c | 1 + drivers/mmc/host/tmio_mmc_pio.c | 1 + 4 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c index 5f89cb83d5f0..187f48a5795a 100644 --- a/drivers/mmc/core/slot-gpio.c +++ b/drivers/mmc/core/slot-gpio.c @@ -221,8 +221,6 @@ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio, ctx->override_cd_active_level = true; ctx->cd_gpio = gpio_to_desc(gpio); - mmc_gpiod_request_cd_irq(host); - return 0; } EXPORT_SYMBOL(mmc_gpio_request_cd); diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c index cc8d4a6099cd..e4a07546f8b6 100644 --- a/drivers/mmc/host/mmc_spi.c +++ b/drivers/mmc/host/mmc_spi.c @@ -1436,6 +1436,7 @@ static int mmc_spi_probe(struct spi_device *spi) host->pdata->cd_debounce); if (status != 0) goto fail_add_host; + mmc_gpiod_request_cd_irq(mmc); } if (host->pdata && host->pdata->flags & MMC_SPI_USE_RO_GPIO) { diff --git a/drivers/mmc/host/sdhci-sirf.c b/drivers/mmc/host/sdhci-sirf.c index 17004531d089..b6db259aea9e 100644 --- a/drivers/mmc/host/sdhci-sirf.c +++ b/drivers/mmc/host/sdhci-sirf.c @@ -94,6 +94,7 @@ static int sdhci_sirf_probe(struct platform_device *pdev) ret); goto err_request_cd; } + mmc_gpiod_request_cd_irq(host->mmc); } return 0; diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c index faf0924e71cb..59d9a7249b2e 100644 --- a/drivers/mmc/host/tmio_mmc_pio.c +++ b/drivers/mmc/host/tmio_mmc_pio.c @@ -1103,6 +1103,7 @@ int tmio_mmc_host_probe(struct tmio_mmc_host **host, tmio_mmc_host_remove(_host); return ret; } + mmc_gpiod_request_cd_irq(mmc); } *host = _host;