netfilter: nft_byteorder: avoid unneeded le/be conversion steps

Florian Westphal · ummakynes · commit 4b8c4eddfc94 · 2016-01-13T14:02:59.000+01:00
David points out that we to three le/be conversions instead
of just one.  Doesn't matter on x86_64 w. gcc, but other
architectures might be less lucky.

Since it also simplifies code just follow his advice.

Fixes: c0f3275f5cb ("nftables: byteorder: provide le/be 64 bit conversion helper")
Suggested-by: David Laight &lt;David.Laight@aculab.com&gt;
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
diff --git a/net/netfilter/nft_byteorder.c b/net/netfilter/nft_byteorder.c
@@ -46,16 +46,14 @@ static void nft_byteorder_eval(const struct nft_expr *expr,
 		switch (priv->op) {
 		case NFT_BYTEORDER_NTOH:
 			for (i = 0; i < priv->len / 8; i++) {
-				src64 = get_unaligned_be64(&src[i]);
-				src64 = be64_to_cpu((__force __be64)src64);
+				src64 = get_unaligned((u64 *)&src[i]);
 				put_unaligned_be64(src64, &dst[i]);
 			}
 			break;
 		case NFT_BYTEORDER_HTON:
 			for (i = 0; i < priv->len / 8; i++) {
 				src64 = get_unaligned_be64(&src[i]);
-				src64 = (__force u64)cpu_to_be64(src64);
-				put_unaligned_be64(src64, &dst[i]);
+				put_unaligned(src64, (u64 *)&dst[i]);
 			}
 			break;
 		}

Original file line number	Diff line number	Diff line change
`@@ -46,16 +46,14 @@ static void nft_byteorder_eval(const struct nft_expr *expr,`
`46`	`46`	`switch (priv->op) {`
`47`	`47`	`case NFT_BYTEORDER_NTOH:`
`48`	`48`	`for (i = 0; i < priv->len / 8; i++) {`
`49`		`- src64 = get_unaligned_be64(&src[i]);`
`50`		`- src64 = be64_to_cpu((__force __be64)src64);`
	`49`	`+ src64 = get_unaligned((u64 *)&src[i]);`
`51`	`50`	`put_unaligned_be64(src64, &dst[i]);`
`52`	`51`	`}`
`53`	`52`	`break;`
`54`	`53`	`case NFT_BYTEORDER_HTON:`
`55`	`54`	`for (i = 0; i < priv->len / 8; i++) {`
`56`	`55`	`src64 = get_unaligned_be64(&src[i]);`
`57`		`- src64 = (__force u64)cpu_to_be64(src64);`
`58`		`- put_unaligned_be64(src64, &dst[i]);`
	`56`	`+ put_unaligned(src64, (u64 *)&dst[i]);`
`59`	`57`	`}`
`60`	`58`	`break;`
`61`	`59`	`}`