[PATCH net-next 1/2] net: ti: icssg: Derive stats array lengths from ARRAY_SIZE

[David CARLIER]

Hi MD,

On Tue, 12 May 2026 at 07:06, MD Danish Anwar <danishanwar at ti.com> wrote:
>
> Replace the manually maintained ICSSG_NUM_MIIG_STATS and
> ICSSG_NUM_PA_STATS constants with ARRAY_SIZE() expressions derived
> directly from the corresponding stat descriptor arrays, so that adding
> new entries to icssg_all_miig_stats[] or icssg_all_pa_stats[] no longer
> requires a separate update to a numeric constant.
>
> To make this self-contained, break the circular include dependency
> between icssg_stats.h and icssg_prueth.h:
>
>   - icssg_stats.h previously included icssg_prueth.h (transitively
>     pulling in icssg_switch_map.h and ETH_GSTRING_LEN).  Replace that
>     with direct includes of <linux/ethtool.h>, <linux/kernel.h> and
>     "icssg_switch_map.h".
>
>   - icssg_prueth.h now includes icssg_stats.h, giving it access to
>     the ARRAY_SIZE-based ICSSG_NUM_MIIG_STATS and ICSSG_NUM_PA_STATS
>     before they are used in the prueth_emac struct and ICSSG_NUM_STATS.
>
> Signed-off-by: MD Danish Anwar <danishanwar at ti.com>
> ---
>  drivers/net/ethernet/ti/icssg/icssg_prueth.h | 3 +--
>  drivers/net/ethernet/ti/icssg/icssg_stats.h  | 7 ++++++-
>  2 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.h b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
> index df93d15c5b78..e2ccecb0a0dd 100644
> --- a/drivers/net/ethernet/ti/icssg/icssg_prueth.h
> +++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
> @@ -43,6 +43,7 @@
>
>  #include "icssg_config.h"
>  #include "icss_iep.h"
> +#include "icssg_stats.h"
>  #include "icssg_switch_map.h"
>
>  #define PRUETH_MAX_MTU          (2000 - ETH_HLEN - ETH_FCS_LEN)
> @@ -57,8 +58,6 @@
>
>  #define ICSSG_MAX_RFLOWS       8       /* per slice */
>
> -#define ICSSG_NUM_PA_STATS     32
> -#define ICSSG_NUM_MIIG_STATS   60
>  /* Number of ICSSG related stats */
>  #define ICSSG_NUM_STATS (ICSSG_NUM_MIIG_STATS + ICSSG_NUM_PA_STATS)
>  #define ICSSG_NUM_STANDARD_STATS 31
> diff --git a/drivers/net/ethernet/ti/icssg/icssg_stats.h b/drivers/net/ethernet/ti/icssg/icssg_stats.h
> index 5ec0b38e0c67..b854eb587c1e 100644
> --- a/drivers/net/ethernet/ti/icssg/icssg_stats.h
> +++ b/drivers/net/ethernet/ti/icssg/icssg_stats.h
> @@ -8,10 +8,15 @@
>  #ifndef __NET_TI_ICSSG_STATS_H
>  #define __NET_TI_ICSSG_STATS_H
>
> -#include "icssg_prueth.h"
> +#include <linux/ethtool.h>
> +#include <linux/kernel.h>
> +#include "icssg_switch_map.h"
>
>  #define STATS_TIME_LIMIT_1G_MS    25000    /* 25 seconds @ 1G */
>
> +#define ICSSG_NUM_MIIG_STATS   ARRAY_SIZE(icssg_all_miig_stats)
> +#define ICSSG_NUM_PA_STATS     ARRAY_SIZE(icssg_all_pa_stats)
> +
>  struct miig_stats_regs {
>         /* Rx */
>         u32 rx_packets;
> --
> 2.34.1
>

One thing that caught my eye: icssg_all_miig_stats[] and
  icssg_all_pa_stats[] are 'static const' arrays in icssg_stats.h with
  ETH_GSTRING_LEN name buffers per entry. Right now only icssg_stats.c
  and icssg_ethtool.c pull them in. After this patch icssg_prueth.h
  includes icssg_stats.h, so every .c in the driver (classifier,
  common, config, mii_cfg, queues, switchdev, ...) ends up with its own
  static-const copy of both tables.

  Would a static_assert() work for what you're after? Something like:

    static const struct icssg_miig_stats icssg_all_miig_stats[] = {
        ...
    };
    static_assert(ARRAY_SIZE(icssg_all_miig_stats) == ICSSG_NUM_MIIG_STATS);

  next to each array, keeping the numeric #defines as-is. Then 2/2 fails
  to build the moment a new entry is added without bumping the count,
  which is the case you're guarding against — without touching the
  include graph.

What do you think ?

Cheers.