Re: [PATCH v3 2/3] Support for perf to probe into SDT markers:

[Hemant Kumar]

On 10/19/2013 09:18 PM, Masami Hiramatsu wrote:
> [...]
> +
> +	/*
> +	 * Find out the .stapsdt.base section.
> +	 * This scn will help us to handle prelinking (if present).
> +	 * Compare the retrieved file offset of the base section with the
> +	 * base address in the description of the SDT note. If its different,
> +	 * then accordingly, adjust the note location.
> +	 */
> +	if (elf_section_by_name(elf, &ehdr, &shdr, SDT_BASE_SCN, NULL))
> +		base_off = shdr.sh_offset;
> +	if (base_off) {
> +		if (tmp->bit32)
> +			key->addr.a32[0] = tmp->addr.a32[0] + base_off -
> +				tmp->addr.a32[1];
> +		else
> +			key->addr.a64[0] = tmp->addr.a64[0] + base_off -
> +				tmp->addr.a64[1];
> +	}
> +	key->bit32 = tmp->bit32;
> +}
> +
> +int search_sdt_note(struct sdt_note *key, struct list_head *sdt_notes,
> +		    const char *target)
> Hmm, this interface looks very odd.
>   - This just finds the first matched sdt_note entry instead of the list.
>     In that case, we don't need to pass the list_head.
>   - If the purpose is just counting the number of matched entries (or just
>     checking existence), we also don't need the list. Just returning the
>     number is enough.
>
> I recommend you to remove the "sdt_notes", and make the caller check
> key->addr is set.

Yeah, list isn't required in this case. Thanks for pointing that out. 
Will change that.

> [...]
--
Thanks
Hemant Kumar

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/