netdev - Re: [PATCH] can: proc: fix rcvlist_* header alignment on 64-bit system

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Message-ID: <CAAMKmodFEXj69mA2nHNfdtJYBTUR+sBpPc_2krm27oKUyVtqKA@mail.gmail.com>
Date:   Sun, 25 Apr 2021 13:40:10 +0200
From:   Erik Flodin <erik@...din.me>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Oliver Hartkopp <socketcan@...tkopp.net>,
        Marc Kleine-Budde <mkl@...gutronix.de>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, linux-can@...r.kernel.org,
        netdev@...r.kernel.org, mailhol.vincent@...adoo.fr
Subject: Re: [PATCH] can: proc: fix rcvlist_* header alignment on 64-bit system

Hi,

On Sun, 25 Apr 2021 at 11:53, Erik Flodin <erik@...din.me> wrote:
> -       seq_puts(m, "  device   can_id   can_mask  function"
> -                       "  userdata   matches  ident\n");
> +       seq_printf(m, "  device   can_id   can_mask  %sfunction%s  %suserdata%s   matches  ident\n",
> +                  pad, pad, pad, pad);
>  }

If a compile-time variant is better I'm happy to change this to e.g.
something like this:

seq_puts(m, "  device   can_id   can_mask  ");
if (IS_ENABLED(CONFIG_64BIT))
        seq_puts(m, "    function          userdata    ");
else
        seq_puts(m, "function  userdata");
seq_puts(m, "   matches  ident\n");

or something like what Vincent suggested:

#ifdef CONFIG_64BIT
#define PAD "    "
#else
#define PAD ""
#endif
...
seq_puts(m, "  device   can_id   can_mask  " PAD "function  " PAD
PAD "userdata   " PAD "matches  ident\n");

None of these versions are really grep friendly though. If that is
needed, a third variant with two full strings can be used instead.
Just let me know which one that's preferred.

// Erik