On 7 September 2016 at 04:38, Baolin Wang <baolin.wang@xxxxxxxxxx> wrote:
> 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 <baolin.wang@xxxxxxxxxx>
> Tested-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
Thanks, applied for next!
Kind regards
Uffe
> ---
> 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
>
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