[PATCH] mmci: calculate remaining bytes at error correctly

[Linus Walleij]

2011/1/30 Russell King - ARM Linux <linux at arm.linux.org.uk>:

> 8<-----
> Subject: [PATCH 2/2] ARM: mmci: round down the bytes transferred on error
>
> We should not report incomplete blocks on error.  Return the number of
> bytes successfully transferred, rounded down to the nearest block.
>
> Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
> ---
>  drivers/mmc/host/mmci.c |    6 +++---
>  1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index 175a623..0de1602 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -289,13 +289,13 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
>                dev_dbg(mmc_dev(host->mmc), "MCI ERROR IRQ (status %08x)\n", status);
>                if (status & MCI_DATACRCFAIL) {
>                        /* Last block was not successful */
> -                       host->data_xfered = ((success - 1) / data->blksz) * data->blksz;
> +                       host->data_xfered = (success - 1) & ~(data->blksz - 1);

Looks equivalent to using the macro round_down() from
<linux/kernel.h> like this:

host->data_xfered = round_down((success - 1), data->blksz);

Maybe that adds a bit to readability...

>                        data->error = -EILSEQ;
>                } else if (status & MCI_DATATIMEOUT) {
> -                       host->data_xfered = success;
> +                       host->data_xfered = success & ~(data->blksz - 1);
>                        data->error = -ETIMEDOUT;
>                } else if (status & (MCI_TXUNDERRUN|MCI_RXOVERRUN)) {
> -                       host->data_xfered = success;
> +                       host->data_xfered = success & ~(data->blksz - 1);
>                        data->error = -EIO;
>                }

Dito on both but just
round_down(success, data->blksz);

Either way it is correct so:
Acked-by: Linus Walleij <linus.walleij at stericsson.com>

Yours,
Linus Walleij