From patchwork Thu Sep 3 08:20:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adrian Hunter X-Patchwork-Id: 11752795 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C9EBB14E5 for ; Thu, 3 Sep 2020 08:20:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC26D2071B for ; Thu, 3 Sep 2020 08:20:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728222AbgICIUc (ORCPT ); Thu, 3 Sep 2020 04:20:32 -0400 Received: from mga05.intel.com ([192.55.52.43]:36764 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726967AbgICIUc (ORCPT ); Thu, 3 Sep 2020 04:20:32 -0400 IronPort-SDR: UAhQwI9nWr5N0Ssk91Enat0eUs15ciWos+Mpf9aZyd9VfUitB9WC+vPWh1uI8SDDj4GleLaAws HrPm3i/171hQ== X-IronPort-AV: E=McAfee;i="6000,8403,9732"; a="242356326" X-IronPort-AV: E=Sophos;i="5.76,385,1592895600"; d="scan'208";a="242356326" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2020 01:20:31 -0700 IronPort-SDR: us9vTGT33QbxjZoviJb7le3HTC8FOUlIec36VMhX5tXlhCcvcPW9B/SKFJcwEJiMvCa3zvNnDf 7Vbl3UaoRlmQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,385,1592895600"; d="scan'208";a="334396201" Received: from slisovsk-lenovo-ideapad-720s-13ikb.fi.intel.com (HELO ahunter-Desktop.fi.intel.com) ([10.237.72.190]) by fmsmga002.fm.intel.com with ESMTP; 03 Sep 2020 01:20:29 -0700 From: Adrian Hunter To: Ulf Hansson Cc: linux-mmc , =?utf-8?q?Pali_Roh=C3=A1r?= , Haibo Chen , Yue Hu , Douglas Anderson , Dmitry Osipenko Subject: [PATCH] mmc: sdio: Use mmc_pre_req() / mmc_post_req() Date: Thu, 3 Sep 2020 11:20:07 +0300 Message-Id: <20200903082007.18715-1-adrian.hunter@intel.com> X-Mailer: git-send-email 2.17.1 Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org SDHCI changed from using a tasklet to finish requests, to using an IRQ thread i.e. commit c07a48c2651965 ("mmc: sdhci: Remove finish_tasklet"). Because this increased the latency to complete requests, a preparatory change was made to complete the request from the IRQ handler if possible i.e. commit 19d2f695f4e827 ("mmc: sdhci: Call mmc_request_done() from IRQ handler if possible"). That alleviated the situation for MMC block devices because the MMC block driver makes use of mmc_pre_req() and mmc_post_req() so that successful requests are completed in the IRQ handler and any DMA unmapping is handled separately in mmc_post_req(). However SDIO was still affected, and an example has been reported with up to 20% degradation in performance. Looking at SDIO I/O helper functions, sdio_io_rw_ext_helper() appeared to be a possible candidate for making use of asynchronous requests within its I/O loops, but analysis revealed that these loops almost never iterate more than once, so the complexity of the change would not be warrented. Instead, mmc_pre_req() and mmc_post_req() are added before and after I/O submission (mmc_wait_for_req) in mmc_io_rw_extended(). This still has the potential benefit of reducing the duration of interrupt handlers, as well as addressing the latency issue for SDHCI. It also seems a more reasonable solution than forcing drivers to do everything in the IRQ handler. Reported-by: Dmitry Osipenko Fixes: c07a48c2651965 ("mmc: sdhci: Remove finish_tasklet") Signed-off-by: Adrian Hunter Tested-by: Dmitry Osipenko --- drivers/mmc/core/sdio_ops.c | 39 +++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 17 deletions(-) diff --git a/drivers/mmc/core/sdio_ops.c b/drivers/mmc/core/sdio_ops.c index 93d346c01110..4c229dd2b6e5 100644 --- a/drivers/mmc/core/sdio_ops.c +++ b/drivers/mmc/core/sdio_ops.c @@ -121,6 +121,7 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn, struct sg_table sgtable; unsigned int nents, left_size, i; unsigned int seg_size = card->host->max_seg_size; + int err; WARN_ON(blksz == 0); @@ -170,28 +171,32 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn, mmc_set_data_timeout(&data, card); - mmc_wait_for_req(card->host, &mrq); + mmc_pre_req(card->host, &mrq); - if (nents > 1) - sg_free_table(&sgtable); + mmc_wait_for_req(card->host, &mrq); if (cmd.error) - return cmd.error; - if (data.error) - return data.error; - - if (mmc_host_is_spi(card->host)) { + err = cmd.error; + else if (data.error) + err = data.error; + else if (mmc_host_is_spi(card->host)) /* host driver already reported errors */ - } else { - if (cmd.resp[0] & R5_ERROR) - return -EIO; - if (cmd.resp[0] & R5_FUNCTION_NUMBER) - return -EINVAL; - if (cmd.resp[0] & R5_OUT_OF_RANGE) - return -ERANGE; - } + err = 0; + else if (cmd.resp[0] & R5_ERROR) + err = -EIO; + else if (cmd.resp[0] & R5_FUNCTION_NUMBER) + err = -EINVAL; + else if (cmd.resp[0] & R5_OUT_OF_RANGE) + err = -ERANGE; + else + err = 0; - return 0; + mmc_post_req(card->host, &mrq, err); + + if (nents > 1) + sg_free_table(&sgtable); + + return err; } int sdio_reset(struct mmc_host *host)