On Sun, Oct 01, 2023 at 01:54:48PM -0500, Mike Christie wrote:
> We are converting tcmu applications to ublk, but have systems with up
> to 1k devices. This patch allows us to configure the ublks_max from
> userspace with the ublks_max modparam.
>
> Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
> ---
> drivers/block/ublk_drv.c | 31 ++++++++++++++++++++++++++++++-
> 1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 18e352f8cd6d..2833a81e05c0 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -2940,7 +2940,36 @@ static void __exit ublk_exit(void)
> module_init(ublk_init);
> module_exit(ublk_exit);
>
> -module_param(ublks_max, int, 0444);
> +static int ublk_set_max_ublks(const char *buf, const struct kernel_param *kp)
> +{
> + unsigned int max;
> + int ret;
> +
> + ret = kstrtouint(buf, 10, &max);
> + if (ret)
> + return ret;
> +
> + if (max > UBLK_MAX_UBLKS) {
> + pr_warn("Invalid ublks_max. Max supported is %d\n",
> + UBLK_MAX_UBLKS);
> + return -EINVAL;
> + }
> +
> + ublks_max = max;
> + return ret;
It might be nice to reuse builtin helper:
return param_set_uint_minmax(buf, kp, 0, UBLK_MAX_UBLKS);
> +}
> +
> +static int ublk_get_max_ublks(char *buf, const struct kernel_param *kp)
> +{
> + return sysfs_emit(buf, "%d\n", ublks_max);
> +}
> +
> +static const struct kernel_param_ops ublk_max_ublks_ops = {
> + .set = ublk_set_max_ublks,
> + .get = ublk_get_max_ublks,
Same with above, '.get = param_get_int,' could be better.
Otherwise, this patch looks fine.
Thanks,
Ming
