clean up kernel_{read,write} & friends v2

[Matthew Wilcox]

On Thu, May 28, 2020 at 08:33:40PM +0100, Al Viro wrote:
> On Thu, May 28, 2020 at 12:22:08PM -0700, Joe Perches wrote:
> 
> > Hard limits at 80 really don't work well, especially with
> > some of the 25+ character length identifiers used today.
> 
> IMO any such identifier is a good reason for a warning.
> 
> The litmus test is actually very simple: how unpleasant would it be
> to mention the identifiers while discussing the code over the phone?

Here's a good example of a function which should be taken out and shot:

int amdgpu_atombios_get_leakage_vddc_based_on_leakage_params(struct amdgpu_devic
e *adev,
...
        switch (frev) {
        case 2:
                switch (crev) {
...
                        if (profile->ucElbVDDC_Num > 0) {
                                for (i = 0; i < profile->ucElbVDDC_Num; i++) {
                                        if (vddc_id_buf[i] == virtual_voltage_id) {
                                                for (j = 0; j < profile->ucLeakageBinNum; j++) {
                                                        if (vbios_voltage_id <= leakage_bin[j]) {
                                                                *vddc = vddc_buf[j * profile->ucElbVDDC_Num + i];

I mean, I get it that AMD want to show off just how studly a monitor they
support, but good grief ...