From patchwork Wed Jul 20 22:02:00 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Per Forlin X-Patchwork-Id: 993182 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p6KM2vc2005149 for ; Wed, 20 Jul 2011 22:02:57 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751536Ab1GTWCZ (ORCPT ); Wed, 20 Jul 2011 18:02:25 -0400 Received: from mail-fx0-f52.google.com ([209.85.161.52]:46171 "EHLO mail-fx0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751998Ab1GTWCW (ORCPT ); Wed, 20 Jul 2011 18:02:22 -0400 Received: by mail-fx0-f52.google.com with SMTP id 18so2327443fxd.11 for ; Wed, 20 Jul 2011 15:02:21 -0700 (PDT) Received: by 10.223.9.217 with SMTP id m25mr912208fam.122.1311199341105; Wed, 20 Jul 2011 15:02:21 -0700 (PDT) Received: from localhost.localdomain (c-3c7b71d5.029-82-6c756e10.cust.bredbandsbolaget.se [213.113.123.60]) by mx.google.com with ESMTPS id d6sm967836fak.10.2011.07.20.15.02.19 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 20 Jul 2011 15:02:20 -0700 (PDT) From: Per Forlin To: linaro-dev@lists.linaro.org, Nicolas Pitre , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, linux-doc@vger.kernel.org, Venkatraman S , Linus Walleij , Kyungmin Park , Arnd Bergmann , Sourav Poddar , Chris Ball , Akinobu Mita , J Freyensee Cc: Randy Dunlap , Per Forlin Subject: [PATCH v3 2/3] mmc: core: add random fault injection Date: Thu, 21 Jul 2011 00:02:00 +0200 Message-Id: <1311199321-4618-3-git-send-email-per.forlin@linaro.org> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1311199321-4618-1-git-send-email-per.forlin@linaro.org> References: <1311199321-4618-1-git-send-email-per.forlin@linaro.org> Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Wed, 20 Jul 2011 22:02:58 +0000 (UTC) This adds support to inject data errors after a completed host transfer. The mmc core will return error even though the host transfer is successful. This simple fault injection proved to be very useful to test the non-blocking error handling in the mmc_blk_issue_rw_rq(). Random faults can also test how the host driver handles pre_req() and post_req() in case of errors. Signed-off-by: Per Forlin --- drivers/mmc/core/core.c | 69 ++++++++++++++++++++++++++++++++++++++++++++ drivers/mmc/core/debugfs.c | 5 +++ include/linux/mmc/host.h | 3 ++ lib/Kconfig.debug | 11 +++++++ 4 files changed, 88 insertions(+), 0 deletions(-) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index ab36c7b..dac2673 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -24,6 +24,11 @@ #include #include +#ifdef CONFIG_FAIL_MMC_REQUEST +#include +#include +#endif + #include #include #include @@ -82,6 +87,66 @@ static void mmc_flush_scheduled_work(void) flush_workqueue(workqueue); } +#ifdef CONFIG_FAIL_MMC_REQUEST + +static DECLARE_FAULT_ATTR(fail_mmc_request); + +/* + * Internal function. Pass the boot param fail_mmc_request to + * the setup fault injection attributes routine. + */ +static int __init setup_fail_mmc_request(char *str) +{ + return setup_fault_attr(&fail_mmc_request, str); +} +__setup("fail_mmc_request=", setup_fail_mmc_request); + +/* + * Internal function. Inject random data errors. + * If mmc_data is NULL no errors are injected. + */ +static void mmc_should_fail_request(struct mmc_host *host, + struct mmc_request *mrq) +{ + struct mmc_command *cmd = mrq->cmd; + struct mmc_data *data = mrq->data; + static const int data_errors[] = { + -ETIMEDOUT, + -EILSEQ, + -EIO, + }; + + if (!data) + return; + + if (cmd->error || data->error || !host->make_it_fail || + !should_fail(&fail_mmc_request, data->blksz * data->blocks)) + return; + + data->error = data_errors[random32() % ARRAY_SIZE(data_errors)]; + data->bytes_xfered = (random32() % (data->bytes_xfered >> 9)) << 9; +} + +static int __init fail_mmc_request_debugfs(void) +{ + return init_fault_attr_dentries(&fail_mmc_request, + "fail_mmc_request"); +} + +#else /* CONFIG_FAIL_MMC_REQUEST */ + +static void mmc_should_fail_request(struct mmc_host *host, + struct mmc_request *mrq) +{ +} + +static int __init fail_mmc_request_debugfs(void) +{ + return 0; +} +#endif /* CONFIG_FAIL_MMC_REQUEST */ + + /** * mmc_request_done - finish processing an MMC request * @host: MMC host which completed request @@ -108,6 +173,8 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq) cmd->error = 0; host->ops->request(host, mrq); } else { + mmc_should_fail_request(host, mrq); + led_trigger_event(host->led, LED_OFF); pr_debug("%s: req done (CMD%u): %d: %08x %08x %08x %08x\n", @@ -2064,6 +2131,8 @@ static int __init mmc_init(void) if (ret) goto unregister_host_class; + fail_mmc_request_debugfs(); + return 0; unregister_host_class: diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c index 998797e..588e76f 100644 --- a/drivers/mmc/core/debugfs.c +++ b/drivers/mmc/core/debugfs.c @@ -188,6 +188,11 @@ void mmc_add_host_debugfs(struct mmc_host *host) root, &host->clk_delay)) goto err_node; #endif +#ifdef CONFIG_FAIL_MMC_REQUEST + if (!debugfs_create_u8("make-it-fail", S_IRUSR | S_IWUSR, + root, &host->make_it_fail)) + goto err_node; +#endif return; err_node: diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 771455f..250b46d 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -303,6 +303,9 @@ struct mmc_host { struct mmc_async_req *areq; /* active async req */ +#ifdef CONFIG_FAIL_MMC_REQUEST + u8 make_it_fail; +#endif unsigned long private[0] ____cacheline_aligned; }; diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c768bcd..c2d1423 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1057,6 +1057,17 @@ config FAIL_IO_TIMEOUT Only works with drivers that use the generic timeout handling, for others it wont do anything. +config FAIL_MMC_REQUEST + bool "Fault-injection capability for MMC IO" + select DEBUG_FS + depends on FAULT_INJECTION && MMC + help + Provide fault-injection capability for MMC IO. + This will make the mmc core return data errors. This is + useful to test the error handling in the mmc block device + and to test how the mmc host driver handles retries from + the block device. + config FAULT_INJECTION_DEBUG_FS bool "Debugfs entries for fault-injection capabilities" depends on FAULT_INJECTION && SYSFS && DEBUG_FS