From 6c689886fbe41b6492bd8ee9334ff66893274810 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 7 Sep 2016 10:38:25 +0800 Subject: [PATCH] mmc: core: Optimize the mmc erase size alignment 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 Signed-off-by: Ulf Hansson --- 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 9ce6c25..d083d2e 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2212,19 +2212,37 @@ 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; -- 2.7.4