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Commit 6c689886 authored by Baolin Wang's avatar Baolin Wang Committed by Ulf Hansson
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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: default avatarBaolin Wang <baolin.wang@linaro.org>
Tested-by: default avatarShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 71085123

drivers/mmc/core/core.c

+26 −8
Original line number Diff line number Diff line
@@ -2212,6 +2212,23 @@ static unsigned int mmc_align_erase_size(struct mmc_card *card, 
{

	unsigned int from_new = *from, nr_new = nr, 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;



		nr_new = round_down(nr_new, card->erase_size);

	} else {

		rem = from_new % card->erase_size;

		if (rem) {

			rem = card->erase_size - rem;
@@ -2225,6 +2242,7 @@ static unsigned int mmc_align_erase_size(struct mmc_card *card, 
		rem = nr_new % card->erase_size;

		if (rem)

			nr_new -= rem;

	}



	if (nr_new == 0)

		return 0;