Re: [Qemu-devel] [PATCH v6] s390x/pci: add common function measurement block

[Cornelia Huck <cohuck@redhat.com>]

On Thu,  3 Jan 2019 11:17:00 +0100
Pierre Morel <pmorel@linux.ibm.com> wrote:

> +static void fmb_update(void *opaque)
> +{
> +    S390PCIBusDevice *pbdev = opaque;
> +    int64_t t = qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL);
> +    int i;
> +
> +    /* Update U bit */
> +    pbdev->fmb.last_update *= 2;
> +    pbdev->fmb.last_update |= UPDATE_U_BIT;
> +    if (fmb_do_update(pbdev, offsetof(ZpciFmb, last_update),
> +                      pbdev->fmb.last_update,
> +                      sizeof(((ZpciFmb *)0)->last_update))) {

I really don't want to be a pain, but... this looks weird. Why not
simply sizeof(pbdev->fmb.last_update)?

> +        return;
> +    }
> +
> +    /* Update FMB sample count */
> +    if (fmb_do_update(pbdev, offsetof(ZpciFmb, sample),
> +                      pbdev->fmb.sample++,
> +                      sizeof(((ZpciFmb *)0)->sample))) {
> +        return;
> +    }
> +
> +    /* Update FMB counters */
> +    for (i = 0; i < ZPCI_FMB_CNT_MAX; i++) {
> +        if (fmb_do_update(pbdev, offsetof(ZpciFmb, counter[i]),
> +                          pbdev->fmb.counter[i],
> +                          sizeof(((ZpciFmb *)0)->counter[0]))) {
> +            return;
> +        }
> +    }
> +
> +    /* Clear U bit and update the time */
> +    pbdev->fmb.last_update = time2tod(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
> +    pbdev->fmb.last_update *= 2;
> +    if (fmb_do_update(pbdev, offsetof(ZpciFmb, last_update),
> +                      pbdev->fmb.last_update,
> +                      sizeof(((ZpciFmb *)0)->last_update))) {
> +        return;
> +    }
> +    timer_mod(pbdev->fmb_timer, t + DEFAULT_MUI);
> +}
> +