On 6 November 2014 04:35, Ben Hutchings <[email protected]> wrote:
> Currently the driver imposes a limit of 256 total minor numbers,
> apparently based on the historic Unix/Linux limit. This is quite
> restrictive, particularly if we raise the maximum number of
> partitions per card to 256 to match sd.
>
> In order to make the full minor number space available we would
> have to replace the static dev_use and name_use arrays with struct
> ida. But we can at least allow use of 256 cards rather than just
> 256 minors, with only a small change.
>
> Signed-off-by: Ben Hutchings <[email protected]>
Thanks! Applied for next.
Kind regards
Uffe
> ---
> drivers/mmc/card/block.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 1fa4c80..d9783da 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -78,13 +78,16 @@ static int perdev_minors = CONFIG_MMC_BLOCK_MINORS;
>
> /*
> * We've only got one major, so number of mmcblk devices is
> - * limited to 256 / number of minors per device.
> + * limited to (1 << 20) / number of minors per device. It is also
> + * currently limited by the size of the static bitmaps below.
> */
> static int max_devices;
>
> -/* 256 minors, so at most 256 separate devices */
> -static DECLARE_BITMAP(dev_use, 256);
> -static DECLARE_BITMAP(name_use, 256);
> +#define MAX_DEVICES 256
> +
> +/* TODO: Replace these with struct ida */
> +static DECLARE_BITMAP(dev_use, MAX_DEVICES);
> +static DECLARE_BITMAP(name_use, MAX_DEVICES);
>
> /*
> * There is one mmc_blk_data per slot.
> @@ -2563,7 +2566,7 @@ static int __init mmc_blk_init(void)
> if (perdev_minors != CONFIG_MMC_BLOCK_MINORS)
> pr_info("mmcblk: using %d minors per device\n",
> perdev_minors);
>
> - max_devices = 256 / perdev_minors;
> + max_devices = min(MAX_DEVICES, (1 << MINORBITS) / perdev_minors);
>
> res = register_blkdev(MMC_BLOCK_MAJOR, "mmc");
> if (res)
>
> --
> Ben Hutchings
> Beware of programmers who carry screwdrivers. - Leonard Brandwein
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