From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932660AbcE2XSu (ORCPT ); Sun, 29 May 2016 19:18:50 -0400 Received: from mailout4.samsung.com ([203.254.224.34]:60147 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932537AbcE2XSs (ORCPT ); Sun, 29 May 2016 19:18:48 -0400 X-AuditID: cbfee68e-f79b26d0000013da-26-574b78d5a7d2 Message-id: <574B78D8.50903@samsung.com> Date: Mon, 30 May 2016 08:18:48 +0900 From: Jaehoon Chung User-Agent: Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-version: 1.0 To: Shawn Lin , Ulf Hansson Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Doug Anderson , linux-rockchip@lists.infradead.org Subject: Re: [PATCH v2 2/2] mmc: dw_mmc: check card present before starting request References: <1464331025-16275-1-git-send-email-shawn.lin@rock-chips.com> In-reply-to: <1464331025-16275-1-git-send-email-shawn.lin@rock-chips.com> Content-type: text/plain; charset=windows-1252 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprLIsWRmVeSWpSXmKPExsWyRsSkSPdqhXe4wYVmZYuzyw6yWVzeNYfN 4sj/fkaLTw/+M1vcebKe1eL42nAHNo/ZDRdZPO5c28PmsXlJvcffWftZPD5vkgtgjeKySUnN ySxLLdK3S+DKmHXlMWvBN/6KmdMOMjUwvuDpYuTkkBAwkTg3+x47hC0mceHeerYuRi4OIYEV jBInLl9igin6sWYjK0RiKaNE6+zj7BDOA0aJvyses4FU8QpoSEyZ180KYrMIqEqsefwezGYT 0JHY/u042CRRgTCJB+v2skLUC0r8mHyPBcQWEfCT2LpjK9hqZoEORolnK6aCJYQFQiXenuhj gdg2j1FieddcsGM5BTwltm6cD9TBAdShJ3H/ohZImFlAXmLzmrfMIPUSAqfYJf7sXAR1kYDE t8mHWEDqJQRkJTYdYIZ4TVLi4IobLBMYxWYhuWkWwtRZSKYuYGRexSiaWpBcUJyUXmSkV5yY W1yal66XnJ+7iREYa6f/PevbwXjzgPUhRgEORiUe3oQ073Ah1sSy4srcQ4ymQEdMZJYSTc4H RnReSbyhsZmRhamJqbGRuaWZkjhvgtTPYCGB9MSS1OzU1ILUovii0pzU4kOMTBycUg2M7oIz ti24b7l8ZvI+tu38n+2O2a2o+GrcFPlJNFbE7PeHyNpEAb+vRu6b+XyYtx5J6NtgtqmG+f+J kxs/ZCwOmW/HXjsx9+0Bg5Wy8+UyGy8dbF9R1vFg7XsXXouP6nOrJgVnTHjy1zN0/88NNeZn 9xh+uHmr75XgnpagbcIq/9YITZgjWqn6WYmlOCPRUIu5qDgRADbHAGSwAgAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrFIsWRmVeSWpSXmKPExsVy+t9jAd2rFd7hBtteyFqcXXaQzeLyrjls Fkf+9zNafHrwn9nizpP1rBbH14Y7sHnMbrjI4nHn2h42j81L6j3+ztrP4vF5k1wAa1QDo01G amJKapFCal5yfkpmXrqtkndwvHO8qZmBoa6hpYW5kkJeYm6qrZKLT4CuW2YO0AFKCmWJOaVA oYDE4mIlfTtME0JD3HQtYBojdH1DguB6jAzQQMIaxoxZVx6zFnzjr5g57SBTA+MLni5GTg4J AROJH2s2skLYYhIX7q1n62Lk4hASWMoo0Tr7ODuE84BR4u+Kx2wgVbwCGhJT5nWDdbAIqEqs efwezGYT0JHY/u04E4gtKhAm8WDdXlaIekGJH5PvsYDYIgJ+Elt3bAXbwCzQwSjxbMVUsISw QKjE2xN9LBDb5jFKLO+ayw6S4BTwlNi6cT5QBwdQh57E/YtaIGFmAXmJzWveMk9gFJiFZMcs hKpZSKoWMDKvYpRILUguKE5KzzXKSy3XK07MLS7NS9dLzs/dxAiO52fSOxgP73I/xCjAwajE w9th5x0uxJpYVlyZe4hRgoNZSYR3TTlQiDclsbIqtSg/vqg0J7X4EKMpMBAmMkuJJucDU01e SbyhsYmZkaWRuaGFkbG5kjjv4//rwoQE0hNLUrNTUwtSi2D6mDg4pRoYTRhPBmWK2fCKmtZU +6hqHJM8IPjIZrnqk4B9dp0eaxsXXPZ3Vo0NvMi92u36+7yLbOuUFzJfnSTCKMbKHurn7Vqy 5njaDPVpn/tDnafxGO10UIw4naF/4tziS6n+GaW7TBUWMUrtW1c/fXNwf34a3xIZ2QP2C09o PNY6Y8Uz8czbRZ/DapqUWIozEg21mIuKEwHHUuB9/QIAAA== DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Shawn, On 05/27/2016 03:37 PM, Shawn Lin wrote: > The main reason to add this check is to avoid unnecessary > mmc_request like the on-going cmd and the corresponding sbc > if the card is removed. Although we have already checked this in > dw_mci_handle_cd for runtime usage of sd card and dw_mci_init_slot > for noremovable devices, but there is a timing gap before it really > calls dw_mci_get_cd as mmc_detect_change needs some delay here. > > Another gain here is that we could save some checkings of card status > after sd card been removed. > > Signed-off-by: Shawn Lin Applied on my repository. Thanks! Best Regards, Jaehoon Chung > > --- > > Changes in v2: > - hold lock before dw_mci_queue_request > > drivers/mmc/host/dw_mmc.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index cb30e91..2b4b3df 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -105,6 +105,7 @@ struct idmac_desc { > static bool dw_mci_reset(struct dw_mci *host); > static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset); > static int dw_mci_card_busy(struct mmc_host *mmc); > +static int dw_mci_get_cd(struct mmc_host *mmc); > > #if defined(CONFIG_DEBUG_FS) > static int dw_mci_req_show(struct seq_file *s, void *v) > @@ -1253,15 +1254,15 @@ static void dw_mci_request(struct mmc_host *mmc, struct mmc_request *mrq) > * atomic, otherwise the card could be removed in between and the > * request wouldn't fail until another card was inserted. > */ > - spin_lock_bh(&host->lock); > > - if (!test_bit(DW_MMC_CARD_PRESENT, &slot->flags)) { > - spin_unlock_bh(&host->lock); > + if (!dw_mci_get_cd(mmc)) { > mrq->cmd->error = -ENOMEDIUM; > mmc_request_done(mmc, mrq); > return; > } > > + spin_lock_bh(&host->lock); > + > dw_mci_queue_request(host, slot, mrq); > > spin_unlock_bh(&host->lock); >