[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>

1 files changed, 23 insertions, 22 deletions

diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
index 639fe8a6ff1e..c2b278138604 100644
--- 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;