Re: [PATCH net-next] ipv6: Implement optimized IPv6 masked address comparison for ARM64
From: Robin Murphy <robin.murphy@arm.com>
Date: 2017-03-17 12:10:33
On 17/03/17 04:42, Subash Abhinov Kasiviswanathan wrote:
Android devices use multiple ip[6]tables for statistics, UID matching and other functionality. Perf output indicated that ip6_do_table was taking a considerable amount of CPU and more that ip_do_table for an equivalent rate. ipv6_masked_addr_cmp was chosen for optimization as there are more instructions required than the equivalent operation in ip_packet_match. Using 128 bit operations helps to reduce the number of instructions for the match on an ARM64 system. This helps to improve UDPv6 DL performance by 40Mbps (860Mbps -> 900Mbps) on a CPU limited system.
After trying to have a look at the codegen difference it makes, I think
I may have found why it's faster ;)
----------
[root@space-channel-5 ~]# cat > ip.c
#include <stdbool.h>
#include <netinet/in.h>
bool
ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m,
const struct in6_addr *a2)
{
const unsigned long *ul1 = (const unsigned long *)a1;
const unsigned long *ulm = (const unsigned long *)m;
const unsigned long *ul2 = (const unsigned long *)a2;
return !!(((ul1[0] ^ ul2[0]) & ulm[0]) |
((ul1[1] ^ ul2[1]) & ulm[1]));
}
bool
ipv6_masked_addr_cmp_new(const struct in6_addr *a1, const struct
in6_addr *m,
const struct in6_addr *a2)
{
const __uint128_t *ul1 = (const __uint128_t *)a1;
const __uint128_t *ulm = (const __uint128_t *)m;
const __uint128_t *ul2 = (const __uint128_t *)a1;
return !!((*ul1 ^ *ul2) & *ulm);
}
[root@space-channel-5 ~]# gcc -c -O2 ip.c
[root@space-channel-5 ~]# objdump -d ip.o
ip.o: file format elf64-littleaarch64
Disassembly of section .text:
0000000000000000 <ipv6_masked_addr_cmp>:
0: a9401847 ldp x7, x6, [x2]
4: a9401003 ldp x3, x4, [x0]
8: f9400025 ldr x5, [x1]
c: f9400422 ldr x2, [x1, #8]
10: ca070060 eor x0, x3, x7
14: ca060081 eor x1, x4, x6
18: 8a050000 and x0, x0, x5
1c: 8a020021 and x1, x1, x2
20: aa010000 orr x0, x0, x1
24: f100001f cmp x0, #0x0
28: 1a9f07e0 cset w0, ne // ne = any
2c: d65f03c0 ret
0000000000000030 <ipv6_masked_addr_cmp_new>:
30: 52800000 mov w0, #0x0 // #0
34: d65f03c0 ret
[root@space-channel-5 ~]# gcc --version
gcc (GCC) 6.3.1 20170306
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
----------
That's clearly not right - I'm not sure quite what undefined behaviour
assumption convinces GCC to optimise the whole thing away, but I do note
that the generic 64-bit version really isn't far off optimal already.
Even if it happens to work out in practice due to inlining behaviour, I
don't think that's something we'd want to rely on.
Robin.
quoted hunk ↗ jump to hunk
Tested on x86_64 UML to check if generic version is used and ARM64 to verify that ARM64 version is used. Signed-off-by: Subash Abhinov Kasiviswanathan <redacted> --- arch/alpha/include/asm/Kbuild | 1 + arch/arc/include/asm/Kbuild | 1 + arch/arm/include/asm/Kbuild | 1 + arch/arm64/include/asm/ipv6.h | 29 +++++++++++++++++++++++++++++ arch/avr32/include/asm/Kbuild | 1 + arch/blackfin/include/asm/Kbuild | 1 + arch/c6x/include/asm/Kbuild | 1 + arch/cris/include/asm/Kbuild | 1 + arch/frv/include/asm/Kbuild | 1 + arch/h8300/include/asm/Kbuild | 1 + arch/hexagon/include/asm/Kbuild | 1 + arch/ia64/include/asm/Kbuild | 1 + arch/m32r/include/asm/Kbuild | 1 + arch/m68k/include/asm/Kbuild | 1 + arch/metag/include/asm/Kbuild | 1 + arch/microblaze/include/asm/Kbuild | 1 + arch/mips/include/asm/Kbuild | 1 + arch/mn10300/include/asm/Kbuild | 1 + arch/nios2/include/asm/Kbuild | 1 + arch/openrisc/include/asm/Kbuild | 1 + arch/parisc/include/asm/Kbuild | 1 + arch/powerpc/include/asm/Kbuild | 1 + arch/s390/include/asm/Kbuild | 1 + arch/score/include/asm/Kbuild | 1 + arch/sh/include/asm/Kbuild | 1 + arch/sparc/include/asm/Kbuild | 1 + arch/tile/include/asm/Kbuild | 1 + arch/um/include/asm/Kbuild | 1 + arch/unicore32/include/asm/Kbuild | 1 + arch/x86/include/asm/Kbuild | 1 + arch/xtensa/include/asm/Kbuild | 1 + include/asm-generic/ipv6.h | 32 ++++++++++++++++++++++++++++++++ include/net/ipv6.h | 20 +------------------- 33 files changed, 92 insertions(+), 19 deletions(-) create mode 100644 arch/arm64/include/asm/ipv6.h create mode 100644 include/asm-generic/ipv6.hdiff --git a/arch/alpha/include/asm/Kbuild b/arch/alpha/include/asm/Kbuild index d103db5..5b7e92b 100644 --- a/arch/alpha/include/asm/Kbuild +++ b/arch/alpha/include/asm/Kbuild@@ -3,6 +3,7 @@ generic-y += clkdev.h generic-y += exec.h generic-y += export.h +generic-y += ipv6.h generic-y += irq_work.h generic-y += mcs_spinlock.h generic-y += mm-arch-hooks.hdiff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild index 63a0401..99f1456 100644 --- a/arch/arc/include/asm/Kbuild +++ b/arch/arc/include/asm/Kbuild@@ -14,6 +14,7 @@ generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kmap_types.hdiff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild index b14e8c7..a0ba9ac 100644 --- a/arch/arm/include/asm/Kbuild +++ b/arch/arm/include/asm/Kbuild@@ -9,6 +9,7 @@ generic-y += errno.h generic-y += exec.h generic-y += ioctl.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += kdebug.h generic-y += local.hdiff --git a/arch/arm64/include/asm/ipv6.h b/arch/arm64/include/asm/ipv6.h new file mode 100644 index 0000000..d49dec6 --- /dev/null +++ b/arch/arm64/include/asm/ipv6.h@@ -0,0 +1,29 @@ +/* Copyright (c) 2017, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#ifndef __ASM_IPV6_H +#define __ASM_IPV6_H + +#include <linux/types.h> + +static inline bool +ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m, + const struct in6_addr *a2) +{ + const __uint128_t *ul1 = (const __uint128_t *)a1; + const __uint128_t *ulm = (const __uint128_t *)m; + const __uint128_t *ul2 = (const __uint128_t *)a1; + + return !!((*ul1 ^ *ul2) & *ulm); +} +#define ipv6_masked_addr_cmp ipv6_masked_addr_cmp +#endif /* __ASM_IPV6_H */diff --git a/arch/avr32/include/asm/Kbuild b/arch/avr32/include/asm/Kbuild index 3d7ef2c..fd6a964 100644 --- a/arch/avr32/include/asm/Kbuild +++ b/arch/avr32/include/asm/Kbuild@@ -6,6 +6,7 @@ generic-y += div64.h generic-y += emergency-restart.h generic-y += exec.h generic-y += futex.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += local.hdiff --git a/arch/blackfin/include/asm/Kbuild b/arch/blackfin/include/asm/Kbuild index 625db8a..f713d85 100644 --- a/arch/blackfin/include/asm/Kbuild +++ b/arch/blackfin/include/asm/Kbuild@@ -12,6 +12,7 @@ generic-y += futex.h generic-y += hw_irq.h generic-y += ioctl.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/c6x/include/asm/Kbuild b/arch/c6x/include/asm/Kbuild index 82619c3..ff8033f 100644 --- a/arch/c6x/include/asm/Kbuild +++ b/arch/c6x/include/asm/Kbuild@@ -20,6 +20,7 @@ generic-y += io.h generic-y += ioctl.h generic-y += ioctls.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/cris/include/asm/Kbuild b/arch/cris/include/asm/Kbuild index 0f5132b..c5b5fa0 100644 --- a/arch/cris/include/asm/Kbuild +++ b/arch/cris/include/asm/Kbuild@@ -15,6 +15,7 @@ generic-y += futex.h generic-y += hardirq.h generic-y += ioctl.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/frv/include/asm/Kbuild b/arch/frv/include/asm/Kbuild index c33b467..0717ffb 100644 --- a/arch/frv/include/asm/Kbuild +++ b/arch/frv/include/asm/Kbuild@@ -1,6 +1,7 @@ generic-y += clkdev.h generic-y += exec.h +generic-y += ipv6.h generic-y += irq_work.h generic-y += mcs_spinlock.h generic-y += mm-arch-hooks.hdiff --git a/arch/h8300/include/asm/Kbuild b/arch/h8300/include/asm/Kbuild index 341740c..0058275 100644 --- a/arch/h8300/include/asm/Kbuild +++ b/arch/h8300/include/asm/Kbuild@@ -23,6 +23,7 @@ generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/hexagon/include/asm/Kbuild b/arch/hexagon/include/asm/Kbuild index 797b64a..4985925 100644 --- a/arch/hexagon/include/asm/Kbuild +++ b/arch/hexagon/include/asm/Kbuild@@ -20,6 +20,7 @@ generic-y += ioctl.h generic-y += ioctls.h generic-y += iomap.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/ia64/include/asm/Kbuild b/arch/ia64/include/asm/Kbuild index 502a91d..cacba4c 100644 --- a/arch/ia64/include/asm/Kbuild +++ b/arch/ia64/include/asm/Kbuild@@ -1,6 +1,7 @@ generic-y += clkdev.h generic-y += exec.h +generic-y += ipv6.h generic-y += irq_work.h generic-y += kvm_para.h generic-y += mcs_spinlock.hdiff --git a/arch/m32r/include/asm/Kbuild b/arch/m32r/include/asm/Kbuild index deb2987..8ed14f5 100644 --- a/arch/m32r/include/asm/Kbuild +++ b/arch/m32r/include/asm/Kbuild@@ -2,6 +2,7 @@ generic-y += clkdev.h generic-y += current.h generic-y += exec.h +generic-y += ipv6.h generic-y += irq_work.h generic-y += kvm_para.h generic-y += mcs_spinlock.hdiff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild index d4f9ccb..1ddfeac 100644 --- a/arch/m68k/include/asm/Kbuild +++ b/arch/m68k/include/asm/Kbuild@@ -9,6 +9,7 @@ generic-y += futex.h generic-y += hw_irq.h generic-y += ioctl.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/metag/include/asm/Kbuild b/arch/metag/include/asm/Kbuild index f9b9df5..2382a6e 100644 --- a/arch/metag/include/asm/Kbuild +++ b/arch/metag/include/asm/Kbuild@@ -16,6 +16,7 @@ generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild index 1732ec1..66b7d8a 100644 --- a/arch/microblaze/include/asm/Kbuild +++ b/arch/microblaze/include/asm/Kbuild@@ -3,6 +3,7 @@ generic-y += barrier.h generic-y += clkdev.h generic-y += device.h generic-y += exec.h +generic-y += ipv6.h generic-y += irq_work.h generic-y += mcs_spinlock.h generic-y += mm-arch-hooks.hdiff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild index 2535c7b..4453f33 100644 --- a/arch/mips/include/asm/Kbuild +++ b/arch/mips/include/asm/Kbuild@@ -5,6 +5,7 @@ generic-y += current.h generic-y += dma-contiguous.h generic-y += emergency-restart.h generic-y += export.h +generic-y += ipv6.h generic-y += irq_work.h generic-y += local64.h generic-y += mcs_spinlock.hdiff --git a/arch/mn10300/include/asm/Kbuild b/arch/mn10300/include/asm/Kbuild index 97f64c7..df55c2b 100644 --- a/arch/mn10300/include/asm/Kbuild +++ b/arch/mn10300/include/asm/Kbuild@@ -2,6 +2,7 @@ generic-y += barrier.h generic-y += clkdev.h generic-y += exec.h +generic-y += ipv6.h generic-y += irq_work.h generic-y += mcs_spinlock.h generic-y += mm-arch-hooks.hdiff --git a/arch/nios2/include/asm/Kbuild b/arch/nios2/include/asm/Kbuild index aaa3c21..d6b13ee 100644 --- a/arch/nios2/include/asm/Kbuild +++ b/arch/nios2/include/asm/Kbuild@@ -22,6 +22,7 @@ generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild index fb01873..0d9ad5a 100644 --- a/arch/openrisc/include/asm/Kbuild +++ b/arch/openrisc/include/asm/Kbuild@@ -25,6 +25,7 @@ generic-y += ioctl.h generic-y += ioctls.h generic-y += ipcbuf.h generic-y += irq.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild index a9909c2..b0e156e 100644 --- a/arch/parisc/include/asm/Kbuild +++ b/arch/parisc/include/asm/Kbuild@@ -8,6 +8,7 @@ generic-y += div64.h generic-y += emergency-restart.h generic-y += exec.h generic-y += hw_irq.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild index 5c4fbc8..f675f7c 100644 --- a/arch/powerpc/include/asm/Kbuild +++ b/arch/powerpc/include/asm/Kbuild@@ -1,6 +1,7 @@ generic-y += clkdev.h generic-y += div64.h generic-y += export.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += local64.hdiff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild index 8aea32f..53a2335 100644 --- a/arch/s390/include/asm/Kbuild +++ b/arch/s390/include/asm/Kbuild@@ -2,6 +2,7 @@ generic-y += asm-offsets.h generic-y += clkdev.h generic-y += dma-contiguous.h generic-y += export.h +generic-y += ipv6.h generic-y += irq_work.h generic-y += mcs_spinlock.h generic-y += mm-arch-hooks.hdiff --git a/arch/score/include/asm/Kbuild b/arch/score/include/asm/Kbuild index 926943a..9405456 100644 --- a/arch/score/include/asm/Kbuild +++ b/arch/score/include/asm/Kbuild@@ -4,6 +4,7 @@ header-y += generic-y += barrier.h generic-y += clkdev.h generic-y += current.h +generic-y += ipv6.h generic-y += irq_work.h generic-y += mcs_spinlock.h generic-y += mm-arch-hooks.hdiff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild index cf2a750..3984834 100644 --- a/arch/sh/include/asm/Kbuild +++ b/arch/sh/include/asm/Kbuild@@ -10,6 +10,7 @@ generic-y += exec.h generic-y += fcntl.h generic-y += ioctl.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kvm_para.hdiff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild index e9e837b..d2acdaf 100644 --- a/arch/sparc/include/asm/Kbuild +++ b/arch/sparc/include/asm/Kbuild@@ -6,6 +6,7 @@ generic-y += div64.h generic-y += emergency-restart.h generic-y += exec.h generic-y += export.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += linkage.hdiff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild index aa48b6e..9487778 100644 --- a/arch/tile/include/asm/Kbuild +++ b/arch/tile/include/asm/Kbuild@@ -12,6 +12,7 @@ generic-y += fcntl.h generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h +generic-y += ipv6.h generic-y += ipcbuf.h generic-y += irq_regs.h generic-y += local.hdiff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild index e9d42aa..b226353 100644 --- a/arch/um/include/asm/Kbuild +++ b/arch/um/include/asm/Kbuild@@ -11,6 +11,7 @@ generic-y += futex.h generic-y += hardirq.h generic-y += hw_irq.h generic-y += io.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/unicore32/include/asm/Kbuild b/arch/unicore32/include/asm/Kbuild index 84205fe..d01d723 100644 --- a/arch/unicore32/include/asm/Kbuild +++ b/arch/unicore32/include/asm/Kbuild@@ -19,6 +19,7 @@ generic-y += hw_irq.h generic-y += ioctl.h generic-y += ioctls.h generic-y += ipcbuf.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild index 5d6a53f..8a68e12 100644 --- a/arch/x86/include/asm/Kbuild +++ b/arch/x86/include/asm/Kbuild@@ -9,5 +9,6 @@ generated-y += xen-hypercalls.h generic-y += clkdev.h generic-y += dma-contiguous.h generic-y += early_ioremap.h +generic-y += ipv6.h generic-y += mcs_spinlock.h generic-y += mm-arch-hooks.hdiff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild index f41408c..dc02075 100644 --- a/arch/xtensa/include/asm/Kbuild +++ b/arch/xtensa/include/asm/Kbuild@@ -9,6 +9,7 @@ generic-y += exec.h generic-y += fcntl.h generic-y += hardirq.h generic-y += ioctl.h +generic-y += ipv6.h generic-y += irq_regs.h generic-y += irq_work.h generic-y += kdebug.hdiff --git a/include/asm-generic/ipv6.h b/include/asm-generic/ipv6.h new file mode 100644 index 0000000..754adac --- /dev/null +++ b/include/asm-generic/ipv6.h@@ -0,0 +1,32 @@ +/* Linux INET6 implementation + * + * Authors: + * Pedro Roque <roque@di.fc.ul.pt> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#ifndef ipv6_masked_addr_cmp +#define ipv6_masked_addr_cmp ipv6_masked_addr_cmp +static inline bool +ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m, + const struct in6_addr *a2) +{ +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 + const unsigned long *ul1 = (const unsigned long *)a1; + const unsigned long *ulm = (const unsigned long *)m; + const unsigned long *ul2 = (const unsigned long *)a2; + + return !!(((ul1[0] ^ ul2[0]) & ulm[0]) | + ((ul1[1] ^ ul2[1]) & ulm[1])); +#else + return !!(((a1->s6_addr32[0] ^ a2->s6_addr32[0]) & m->s6_addr32[0]) | + ((a1->s6_addr32[1] ^ a2->s6_addr32[1]) & m->s6_addr32[1]) | + ((a1->s6_addr32[2] ^ a2->s6_addr32[2]) & m->s6_addr32[2]) | + ((a1->s6_addr32[3] ^ a2->s6_addr32[3]) & m->s6_addr32[3])); +#endif +} +#endifdiff --git a/include/net/ipv6.h b/include/net/ipv6.h index dbf0abb..08ad1a98 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h@@ -21,6 +21,7 @@ #include <net/flow.h> #include <net/flow_dissector.h> #include <net/snmp.h> +#include <asm/ipv6.h> #define SIN6_LEN_RFC2133 24@@ -385,25 +386,6 @@ static inline int ipv6_addr_cmp(const struct in6_addr *a1, const struct in6_addr return memcmp(a1, a2, sizeof(struct in6_addr)); } -static inline bool -ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m, - const struct in6_addr *a2) -{ -#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 - const unsigned long *ul1 = (const unsigned long *)a1; - const unsigned long *ulm = (const unsigned long *)m; - const unsigned long *ul2 = (const unsigned long *)a2; - - return !!(((ul1[0] ^ ul2[0]) & ulm[0]) | - ((ul1[1] ^ ul2[1]) & ulm[1])); -#else - return !!(((a1->s6_addr32[0] ^ a2->s6_addr32[0]) & m->s6_addr32[0]) | - ((a1->s6_addr32[1] ^ a2->s6_addr32[1]) & m->s6_addr32[1]) | - ((a1->s6_addr32[2] ^ a2->s6_addr32[2]) & m->s6_addr32[2]) | - ((a1->s6_addr32[3] ^ a2->s6_addr32[3]) & m->s6_addr32[3])); -#endif -} - static inline void ipv6_addr_prefix(struct in6_addr *pfx, const struct in6_addr *addr, int plen)