On 3/31/23 06:31, Chaitanya Kulkarni wrote:
> Right now we don't check for valid module parameter value for
> block size, that allows user to set negative values.
>
> Add a callback to error out when block size value is set < 1 before
> module is loaded.
>
> Signed-off-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
> ---
> drivers/block/null_blk/main.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
> index f55d88ebd7e6..d8d79c66a7aa 100644
> --- a/drivers/block/null_blk/main.c
> +++ b/drivers/block/null_blk/main.c
> @@ -190,8 +190,23 @@ static int g_gb = 250;
> device_param_cb(gb, &null_gb_param_ops, &g_gb, 0444);
> MODULE_PARM_DESC(gb, "Size in GB");
>
> +static int null_set_bs(const char *s, const struct kernel_param *kp)
> +{
> + int ret;
> +
> + ret = null_param_store_int(s, kp->arg, 512, INT_MAX);
> + if (ret)
> + pr_err("valid range for bs value [512 ... %d]\n", INT_MAX);
This is is only checking the range. block sizes must be power-of-2 as well but
that is not checked. And for the range, block size up to INT_MAX ? That is not
very reasonable.
> + return ret;
> +}
> +
> +static const struct kernel_param_ops null_bs_param_ops = {
> + .set = null_set_bs,
> + .get = param_get_int,
> +};
> +
> static int g_bs = 512;
> -module_param_named(bs, g_bs, int, 0444);
> +device_param_cb(bs, &null_bs_param_ops, &g_bs, 0444);
> MODULE_PARM_DESC(bs, "Block size (in bytes)");
>
> static int g_max_sectors;
--
Damien Le Moal
Western Digital Research
