Hello Matthew, On 9/12/19 1:19 PM, Matthew Wilcox wrote: > On Wed, Sep 11, 2019 at 11:46:36AM -0300, André Almeida wrote: >> >> -static int nr_devices = 1; >> +static unsigned int nr_devices = 1; >> module_param(nr_devices, int, 0444); > > ^^^ you forgot to change the module_param to match > >> + if (!nr_devices) { >> + pr_err("null_blk: invalid number of devices\n"); >> + return -EINVAL; >> + } > > I don't think this is necessary. > Could you explain why you don't think is necessary? As I see, the module can't be used without any /dev/nullb* device, so why we should load it? Thanks, André