Re: [KJ] [PATCH] net/core/flow.c: compare data with memcmp

From: Nishanth Aravamudan
Date: Sun Dec 31 2006 - 14:49:52 EST


On 31.12.2006 [17:37:05 +0100], Daniel Marjam?ki wrote:
> From: Daniel Marjamäki
> This has been tested by me.
> Signed-off-by: Daniel Marjamäki <daniel.marjamaki@xxxxxxxxx>
> --- linux-2.6.20-rc2/net/core/flow.c 2006-12-27 09:59:56.000000000 +0100
> +++ linux/net/core/flow.c 2006-12-31 18:26:06.000000000 +0100
> @@ -144,29 +144,16 @@ typedef u32 flow_compare_t;
>
> extern void flowi_is_missized(void);
>
> -/* I hear what you're saying, use memcmp. But memcmp cannot make
> - * important assumptions that we can here, such as alignment and
> - * constant size.
> - */
> static int flow_key_compare(struct flowi *key1, struct flowi *key2)
> {
> - flow_compare_t *k1, *k1_lim, *k2;
> - const int n_elem = sizeof(struct flowi) / sizeof(flow_compare_t);
> -
> if (sizeof(struct flowi) % sizeof(flow_compare_t))
> flowi_is_missized();
>
> - k1 = (flow_compare_t *) key1;
> - k1_lim = k1 + n_elem;
> -
> - k2 = (flow_compare_t *) key2;
> -
> - do {
> - if (*k1++ != *k2++)
> - return 1;
> - } while (k1 < k1_lim);
> + /* Number of elements to compare */
> + const int n_elem = sizeof(struct flowi) / sizeof(flow_compare_t);
>
> - return 0;
> + /* Compare all elements in key1 and key2. */
> + return memcmp(key1, key2, n_elem * sizeof(flow_compare_t));
> }

Small nit, I don't think either of your comments make the code any
clearer than the code on its own, so drop them both.

Thanks,
Nish

--
Nishanth Aravamudan <nacc@xxxxxxxxxx>
IBM Linux Technology Center
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