From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baolin Wang Subject: [PATCH v4 3/3] mmc: core: Optimize the mmc erase size alignment Date: Tue, 6 Sep 2016 10:55:12 +0800 Message-ID: <8f20dfea761960fd9bbcb6a0ce3ae0178e039b31.1473130123.git.baolin.wang@linaro.org> References: <2b6b5b930d0f37a219d5786a6b56b17516a90abd.1473130123.git.baolin.wang@linaro.org> Return-path: In-Reply-To: <2b6b5b930d0f37a219d5786a6b56b17516a90abd.1473130123.git.baolin.wang@linaro.org> In-Reply-To: <2b6b5b930d0f37a219d5786a6b56b17516a90abd.1473130123.git.baolin.wang@linaro.org> References: <2b6b5b930d0f37a219d5786a6b56b17516a90abd.1473130123.git.baolin.wang@linaro.org> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-mmc@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 5f93eef..e014949 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