Re: [PATCH v3 1/5] seq_file: provide an analogue of print_hex_dump()

Geert Uytterhoeven
2014-09-01T08:58:56Z

Hi Andy,

On Mon, Sep 1, 2014 at 10:36 AM, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>> ... and extra copying for no good reason. Why not check that we have
>> enough space in buffer and generate directly into it? See what e.g.
>> seq_escape() is doing...
>
> What about this variant?

I think it needs a call to seq_set_overflow() in case the buffer is too small,
so the caller will retry with a bigger buffer.

>
> @@ -794,6 +795,47 @@ void seq_pad(struct seq_file *m, char c)
> }
> EXPORT_SYMBOL(seq_pad);
>
> +/* Analogue of print_hex_dump() */
> +void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
> + int rowsize, int groupsize, const void *buf, size_t len,
> + bool ascii)
> +{
> + const u8 *ptr = buf;
> + int i, linelen, remaining = len;
> + int ret;
> +
> + if (rowsize != 16 && rowsize != 32)
> + rowsize = 16;
> +
> + for (i = 0; i < len; i += rowsize) {
> + linelen = min(remaining, rowsize);
> + remaining -= rowsize;
> +
> + ret = seq_printf(m, "%s", prefix_str);
> + if (ret < 0)
> + break;
> +
> + if (prefix_type == DUMP_PREFIX_ADDRESS)
> + ret = seq_printf(m, "%p: ", ptr + i);
> + else if (prefix_type == DUMP_PREFIX_OFFSET)
> + ret = seq_printf(m, "%.8x: ", i);
> + if (ret < 0)
> + break;
> +
> + if (m->size < m->count + groupsize * 2 + 1)
> + break;
> +
> + hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
> + m->buf + m->count, m->size - m->count,
> + ascii);
> +
> + ret = seq_putc(m, '\n');
> + if (ret < 0)
> + break;
> + }
> +}
> +EXPORT_SYMBOL(seq_hex_dump);

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds