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SubjectRe: [PATCH 10/23] perf tools: Introduce swap_header function
Date
On Wed, 17 Jul 2013 19:49:50 +0200, Jiri Olsa wrote:
> Introducing swap_header function to make the swapping
> code more clear and extensible.

[SNIP]
>
> +static int swap_header(struct perf_file_header *header)
> +{
> + mem_bswap_64(header, offsetof(struct perf_file_header, adds_features));
> +
> + if (header->size != sizeof(*header)) {
> + /* Support the previous format */
> + if (header->size == offsetof(typeof(*header), adds_features))
> + bitmap_zero(header->adds_features, HEADER_FEAT_BITS);
> + else
> + return -1;
> + } else
> + swap_features(header->adds_features);
> +
> + return 0;
> +}
> +
> int perf_file_header__read(struct perf_file_header *header,
> struct perf_header *ph, int fd)
> {
> @@ -2562,19 +2578,8 @@ int perf_file_header__read(struct perf_file_header *header,
> return -1;
> }
>
> - if (ph->needs_swap) {
> - mem_bswap_64(header, offsetof(struct perf_file_header,
> - adds_features));
> - }
> -
> - if (header->size != sizeof(*header)) {
> - /* Support the previous format */
> - if (header->size == offsetof(typeof(*header), adds_features))
> - bitmap_zero(header->adds_features, HEADER_FEAT_BITS);
> - else
> - return -1;
> - } else if (ph->needs_swap)
> - swap_features(header->adds_features);
> + if (ph->needs_swap && swap_header(header))
> + return -1;

Doesn't it change existing behavior? It looks like supporting previous
format on a same endian machines will be removed by this patch.

Thanks,
Namhyung


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