Re: [PATCH net-next 2/3] net: mscc: ocelot: Implement port policers via tc command

Andrew Lunn
2019-05-02T12:33:16Z

Hi Joergen

> +
> +#define MSCC_RC(expr) \
> + do { \
> + int __rc__ = (expr); \
> + if (__rc__ < 0) \
> + return __rc__; \
> + } \
> + while (0)

I'm sure checkpatch warned about this. A return inside a macros is a
bad idea. I inherited code doing this, and broke it when adding
locking, because it was not obvious there was a return.

> +
> +/* The following two functions do the same as in iproute2 */
> +#define TIME_UNITS_PER_SEC 1000000
> +static unsigned int tc_core_tick2time(unsigned int tick)
> +{
> + return (tick * (u32)PSCHED_TICKS2NS(1)) / 1000;
> +}
> +
> +static unsigned int tc_calc_xmitsize(u64 rate, unsigned int ticks)
> +{
> + return div_u64(rate * tc_core_tick2time(ticks), TIME_UNITS_PER_SEC);
> +}

Should these but put somewhere others can use them?

> +
> +enum mscc_qos_rate_mode {
> + MSCC_QOS_RATE_MODE_DISABLED, /* Policer/shaper disabled */
> + MSCC_QOS_RATE_MODE_LINE, /* Measure line rate in kbps incl. IPG */
> + MSCC_QOS_RATE_MODE_DATA, /* Measures data rate in kbps excl. IPG */
> + MSCC_QOS_RATE_MODE_FRAME, /* Measures frame rate in fps */
> + __MSCC_QOS_RATE_MODE_END,
> + NUM_MSCC_QOS_RATE_MODE = __MSCC_QOS_RATE_MODE_END,
> + MSCC_QOS_RATE_MODE_MAX = __MSCC_QOS_RATE_MODE_END - 1,
> +};
> +
> +/* Round x divided by y to nearest integer. x and y are integers */
> +#define MSCC_ROUNDING_DIVISION(x, y) (((x) + ((y) / 2)) / (y))

linux/kernel.h defines DIV_ROUND_UP(). Maybe add DIV_ROUND_DOWN()?

> +
> +/* Round x divided by y to nearest higher integer. x and y are integers */
> +#define MSCC_DIV_ROUND_UP(x, y) (((x) + (y) - 1) / (y))

DIV_ROUND_UP() ?

> + /* Limit to maximum values */
> + pir = min_t(u32, GENMASK(15, 0), pir);
> + cir = min_t(u32, GENMASK(15, 0), cir);
> + pbs = min_t(u32, pbs_max, pbs);
> + cbs = min_t(u32, cbs_max, cbs);

If it does need to limit, maybe return -EOPNOTSUPP?

> +int ocelot_port_policer_add(struct ocelot_port *port,
> + struct tcf_police *p)
> +{
> + struct ocelot *ocelot = port->ocelot;
> + struct qos_policer_conf pp;
> +
> + if (!p)
> + return -EINVAL;
> +
> + netdev_dbg(port->dev,
> + "result %d ewma_rate %u burst %lld mtu %u mtu_pktoks %lld\n",
> + p->params->tcfp_result,
> + p->params->tcfp_ewma_rate,
> + p->params->tcfp_burst,
> + p->params->tcfp_mtu,
> + p->params->tcfp_mtu_ptoks);
> +
> + if (p->params->rate_present)
> + netdev_dbg(port->dev,
> + "rate: rate %llu mult %u over %u link %u shift %u\n",
> + p->params->rate.rate_bytes_ps,
> + p->params->rate.mult,
> + p->params->rate.overhead,
> + p->params->rate.linklayer,
> + p->params->rate.shift);
> +
> + if (p->params->peak_present)
> + netdev_dbg(port->dev,
> + "peak: rate %llu mult %u over %u link %u shift %u\n",
> + p->params->peak.rate_bytes_ps,
> + p->params->peak.mult,
> + p->params->peak.overhead,
> + p->params->peak.linklayer,
> + p->params->peak.shift);
> +
> + memset(&pp, 0, sizeof(pp));

Rather than memset, you can do:

struct qos_policer_conf pp = { 0 };

Andrew