[XFRM] IPV6: Optimize __xfrm_tunnel_alloc_spi().

| % size old/net/ipv6/xfrm6_tunnel.o new/net/ipv6/xfrm6_tunnel.o
|    text	   data	    bss	    dec	    hex	filename
|    1606	     40	   2080	   3726	    e8e	old/net/ipv6/xfrm6_tunnel.o
|    1574	     40	   2080	   3694	    e6e	new/net/ipv6/xfrm6_tunnel.o

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
index 639fe8a..c2b2781 100644 (file)
--- a/net/ipv6/xfrm6_tunnel.c
+++ b/net/ipv6/xfrm6_tunnel.c
@@ -140,12 +140,26 @@ __be32 xfrm6_tunnel_spi_lookup(xfrm_address_t *saddr)
 
 EXPORT_SYMBOL(xfrm6_tunnel_spi_lookup);
 
+static int __xfrm6_tunnel_spi_check(u32 spi)
+{
+       struct xfrm6_tunnel_spi *x6spi;
+       int index = xfrm6_tunnel_spi_hash_byspi(spi);
+       struct hlist_node *pos;
+
+       hlist_for_each_entry(x6spi, pos,
+                            &xfrm6_tunnel_spi_byspi[index],
+                            list_byspi) {
+               if (x6spi->spi == spi)
+                       return -1;
+       }
+       return index;
+}
+
 static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
 {
        u32 spi;
        struct xfrm6_tunnel_spi *x6spi;
-       struct hlist_node *pos;
-       unsigned index;
+       int index;
 
        if (xfrm6_tunnel_spi < XFRM6_TUNNEL_SPI_MIN ||
            xfrm6_tunnel_spi >= XFRM6_TUNNEL_SPI_MAX)
@@ -154,32 +168,19 @@ static u32 __xfrm6_tunnel_alloc_spi(xfrm_address_t *saddr)
                xfrm6_tunnel_spi++;
 
        for (spi = xfrm6_tunnel_spi; spi <= XFRM6_TUNNEL_SPI_MAX; spi++) {
-               index = xfrm6_tunnel_spi_hash_byspi(spi);
-               hlist_for_each_entry(x6spi, pos,
-                                    &xfrm6_tunnel_spi_byspi[index],
-                                    list_byspi) {
-                       if (x6spi->spi == spi)
-                               goto try_next_1;
-               }
-               xfrm6_tunnel_spi = spi;
-               goto alloc_spi;
-try_next_1:;
+               index = __xfrm6_tunnel_spi_check(spi);
+               if (index >= 0)
+                       goto alloc_spi;
        }
        for (spi = XFRM6_TUNNEL_SPI_MIN; spi < xfrm6_tunnel_spi; spi++) {
-               index = xfrm6_tunnel_spi_hash_byspi(spi);
-               hlist_for_each_entry(x6spi, pos,
-                                    &xfrm6_tunnel_spi_byspi[index],
-                                    list_byspi) {
-                       if (x6spi->spi == spi)
-                               goto try_next_2;
-               }
-               xfrm6_tunnel_spi = spi;
-               goto alloc_spi;
-try_next_2:;
+               index = __xfrm6_tunnel_spi_check(spi);
+               if (index >= 0)
+                       goto alloc_spi;
        }
        spi = 0;
        goto out;
 alloc_spi:
+       xfrm6_tunnel_spi = spi;
        x6spi = kmem_cache_alloc(xfrm6_tunnel_spi_kmem, GFP_ATOMIC);
        if (!x6spi)
                goto out;