From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934458AbcIGCjV (ORCPT ); Tue, 6 Sep 2016 22:39:21 -0400 Received: from mail-pf0-f181.google.com ([209.85.192.181]:36548 "EHLO mail-pf0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934206AbcIGCjT (ORCPT ); Tue, 6 Sep 2016 22:39:19 -0400 From: Baolin Wang To: ulf.hansson@linaro.org Cc: adrian.hunter@intel.com, rmk+kernel@arm.linux.org.uk, shawn.lin@rock-chips.com, dianders@chromium.org, heiko@sntech.de, david@protonic.nl, hdegoede@redhat.com, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, broonie@kernel.org, linus.walleij@linaro.org, baolin.wang@linaro.org Subject: [PATCH v5 2/2] mmc: core: Optimize the mmc erase size alignment Date: Wed, 7 Sep 2016 10:38:25 +0800 Message-Id: X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <48ff46b96e01df36aa5d1c2daf1091d2ec2e729f.1473215578.git.baolin.wang@linaro.org> References: <48ff46b96e01df36aa5d1c2daf1091d2ec2e729f.1473215578.git.baolin.wang@linaro.org> In-Reply-To: <48ff46b96e01df36aa5d1c2daf1091d2ec2e729f.1473215578.git.baolin.wang@linaro.org> References: <48ff46b96e01df36aa5d1c2daf1091d2ec2e729f.1473215578.git.baolin.wang@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In most cases the 'card->erase_size' is power of 2, then the round_up/down() function is more efficient than '%' operation when the 'card->erase_size' is power of 2. Signed-off-by: Baolin Wang Tested-by: Shawn Lin --- drivers/mmc/core/core.c | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 11b4897..4264ac6 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2209,19 +2209,37 @@ static unsigned int mmc_align_erase_size(struct mmc_card *card, { unsigned int from_new = *from, nr_new = nr, rem; - rem = from_new % card->erase_size; - if (rem) { - rem = card->erase_size - rem; - from_new += rem; + /* + * When the 'card->erase_size' is power of 2, we can use round_up/down() + * to align the erase size efficiently. + */ + if (is_power_of_2(card->erase_size)) { + unsigned int temp = from_new; + + from_new = round_up(temp, card->erase_size); + rem = from_new - temp; + if (nr_new > rem) nr_new -= rem; else return 0; - } - rem = nr_new % card->erase_size; - if (rem) - nr_new -= rem; + nr_new = round_down(nr_new, card->erase_size); + } else { + rem = from_new % card->erase_size; + if (rem) { + rem = card->erase_size - rem; + from_new += rem; + if (nr_new > rem) + nr_new -= rem; + else + return 0; + } + + rem = nr_new % card->erase_size; + if (rem) + nr_new -= rem; + } if (nr_new == 0) return 0; -- 1.7.9.5