From patchwork Mon Aug 29 13:35:58 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Per Forlin X-Patchwork-Id: 1107902 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 p7TDac6s029554 for ; Mon, 29 Aug 2011 13:36:43 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753684Ab1H2Ngn (ORCPT ); Mon, 29 Aug 2011 09:36:43 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:33306 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753674Ab1H2Ngn (ORCPT ); Mon, 29 Aug 2011 09:36:43 -0400 Received: by mail-bw0-f46.google.com with SMTP id 11so4160433bke.19 for ; Mon, 29 Aug 2011 06:36:42 -0700 (PDT) Received: by 10.204.13.69 with SMTP id b5mr2039878bka.289.1314625002258; Mon, 29 Aug 2011 06:36:42 -0700 (PDT) Received: from localhost.localdomain (c-c37f71d5.029-82-6c756e10.cust.bredbandsbolaget.se [213.113.127.195]) by mx.google.com with ESMTPS id m18sm1220341bkt.51.2011.08.29.06.36.40 (version=TLSv1/SSLv3 cipher=OTHER); Mon, 29 Aug 2011 06:36:41 -0700 (PDT) From: Per Forlin To: linaro-dev@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-mmc@vger.kernel.org, Venkatraman S , Russell King - ARM Linux , Santosh , Balaji T Krishnamoorthy , Sourav Poddar Cc: Chris Ball , Per Forlin Subject: [PATCH 1/2] mmc: core: clarify how to use post_req in case of errors Date: Mon, 29 Aug 2011 15:35:58 +0200 Message-Id: <1314624959-4634-2-git-send-email-per.forlin@linaro.org> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1314624959-4634-1-git-send-email-per.forlin@linaro.org> References: <1314624959-4634-1-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]); Mon, 29 Aug 2011 13:36:44 +0000 (UTC) The err condition in post_req() is set to undo a call made to pre_req() that hasn't been started yet. The err condition is not set if an MMC request returns error. Signed-off-by: Per Forlin --- drivers/mmc/core/core.c | 6 ++++++ include/linux/mmc/host.h | 3 +++ 2 files changed, 9 insertions(+), 0 deletions(-) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 91a0a74..542aa06 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -279,8 +279,14 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host, mmc_wait_for_req_done(host, host->areq->mrq); err = host->areq->err_check(host->card, host->areq); if (err) { + /* post process the completed failed request */ mmc_post_req(host, host->areq->mrq, 0); if (areq) + /* + * Cancel the new prepared request, because + * it can't run until the failed + * request has been properly handled. + */ mmc_post_req(host, areq->mrq, -EINVAL); host->areq = NULL; diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 1d09562..7896fb4 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -108,6 +108,9 @@ struct mmc_host_ops { * It is optional for the host to implement pre_req and post_req in * order to support double buffering of requests (prepare one * request while another request is active). + * pre_req() must always be followed by a post_req(). + * To undo a call made to pre_req(), call post_req() with + * a nonzero err condition. */ void (*post_req)(struct mmc_host *host, struct mmc_request *req, int err);