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2007-04-25[SK_BUFF]: Remove skb_add_mtu() leftoversArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2007-04-25[NETLINK]: Introduce nlmsg_hdr() helperArnaldo Carvalho de Melo
For the common "(struct nlmsghdr *)skb->data" sequence, so that we reduce the number of direct accesses to skb->data and for consistency with all the other cast skb member helpers. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Convert skb->end to sk_buff_data_tArnaldo Carvalho de Melo
Now to convert the last one, skb->data, that will allow many simplifications and removal of some of the offset helpers. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Convert skb->tail to sk_buff_data_tArnaldo Carvalho de Melo
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes on 64bit architectures, allowing us to combine the 4 bytes hole left by the layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4 64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN... :-) Many calculations that previously required that skb->{transport,network, mac}_header be first converted to a pointer now can be done directly, being meaningful as offsets or pointers. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Use offsets for skb->{mac,network,transport}_header on 64bit ↵Arnaldo Carvalho de Melo
architectures With this we save 8 bytes per network packet, leaving a 4 bytes hole to be used in further shrinking work, likely with the offsetization of other pointers, such as ->{data,tail,end}, at the cost of adds, that were minimized by the usual practice of setting skb->{mac,nh,n}.raw to a local variable that is then accessed multiple times in each function, it also is not more expensive than before with regards to most of the handling of such headers, like setting one of these headers to another (transport to network, etc), or subtracting, adding to/from it, comparing them, etc. Now we have this layout for sk_buff on a x86_64 machine: [acme@mica net-2.6.22]$ pahole vmlinux sk_buff struct sk_buff { struct sk_buff * next; /* 0 8 */ struct sk_buff * prev; /* 8 8 */ struct rb_node rb; /* 16 24 */ struct sock * sk; /* 40 8 */ ktime_t tstamp; /* 48 8 */ struct net_device * dev; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ struct net_device * input_dev; /* 64 8 */ sk_buff_data_t transport_header; /* 72 4 */ sk_buff_data_t network_header; /* 76 4 */ sk_buff_data_t mac_header; /* 80 4 */ /* XXX 4 bytes hole, try to pack */ struct dst_entry * dst; /* 88 8 */ struct sec_path * sp; /* 96 8 */ char cb[48]; /* 104 48 */ /* cacheline 2 boundary (128 bytes) was 24 bytes ago*/ unsigned int len; /* 152 4 */ unsigned int data_len; /* 156 4 */ unsigned int mac_len; /* 160 4 */ union { __wsum csum; /* 4 */ __u32 csum_offset; /* 4 */ }; /* 164 4 */ __u32 priority; /* 168 4 */ __u8 local_df:1; /* 172 1 */ __u8 cloned:1; /* 172 1 */ __u8 ip_summed:2; /* 172 1 */ __u8 nohdr:1; /* 172 1 */ __u8 nfctinfo:3; /* 172 1 */ __u8 pkt_type:3; /* 173 1 */ __u8 fclone:2; /* 173 1 */ __u8 ipvs_property:1; /* 173 1 */ /* XXX 2 bits hole, try to pack */ __be16 protocol; /* 174 2 */ void (*destructor)(struct sk_buff *); /* 176 8 */ struct nf_conntrack * nfct; /* 184 8 */ /* --- cacheline 3 boundary (192 bytes) --- */ struct sk_buff * nfct_reasm; /* 192 8 */ struct nf_bridge_info *nf_bridge; /* 200 8 */ __u16 tc_index; /* 208 2 */ __u16 tc_verd; /* 210 2 */ dma_cookie_t dma_cookie; /* 212 4 */ __u32 secmark; /* 216 4 */ __u32 mark; /* 220 4 */ unsigned int truesize; /* 224 4 */ atomic_t users; /* 228 4 */ unsigned char * head; /* 232 8 */ unsigned char * data; /* 240 8 */ unsigned char * tail; /* 248 8 */ /* --- cacheline 4 boundary (256 bytes) --- */ unsigned char * end; /* 256 8 */ }; /* size: 264, cachelines: 5 */ /* sum members: 260, holes: 1, sum holes: 4 */ /* bit holes: 1, sum bit holes: 2 bits */ /* last cacheline: 8 bytes */ On 32 bits nothing changes, and pointers continue to be used with the compiler turning all this abstraction layer into dust. But there are some sk_buff validation tricks that are now possible, humm... :-) Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: unions of just one member don't get anything done, kill themArnaldo Carvalho de Melo
Renaming skb->h to skb->transport_header, skb->nh to skb->network_header and skb->mac to skb->mac_header, to match the names of the associated helpers (skb[_[re]set]_{transport,network,mac}_header). Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_network_header_lenArnaldo Carvalho de Melo
For the common sequence "skb->h.raw - skb->nh.raw", similar to skb->mac_len, that is precalculated tho, don't think we need to bloat skb with one more member, so just use this new helper, reducing the number of non-skbuff.h references to the layer headers even more. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[KBUILD]: Unifdef headers changed by the skb layer header refactoringsArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[NETFILTER]: ctnetlink: add support for internal tcp connection tracking ↵Pablo Neira Ayuso
flags handling This patch let userspace programs set the IP_CT_TCP_BE_LIBERAL flag to force the pickup of established connections. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[NETFILTER]: nf_conntrack: add nf_copy() to safely copy members in skbYasuyuki Kozakai
This unifies the codes to copy netfilter related datas. Before copying, nf_copy() puts original members in destination skb. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[NETFILTER]: nf_conntrack: add __nf_copy() to copy members in skbYasuyuki Kozakai
This unifies the codes to copy netfilter related datas. Note that __nf_copy() assumes destination skb doesn't have any netfilter related members. Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[JHASH]: Use const in jhash2Patrick McHardy
Use const to avoid forcing users to cast const data. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[NETFILTER]: nfnetlink: use mutex instead of semaphorePatrick McHardy
Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[NETFILTER]: Remove IPv4 only connection tracking/NATPatrick McHardy
Remove the obsolete IPv4 only connection tracking/NAT as scheduled in feature-removal-schedule. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_transport_header(skb)Arnaldo Carvalho de Melo
For the places where we need a pointer to the transport header, it is still legal to touch skb->h.raw directly if just adding to, subtracting from or setting it to another layer header. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce ipipv6_hdr(), remove skb->h.ipv6hArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce ipip_hdr(), remove skb->h.ipiphArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce tcp_hdr(), remove skb->h.thArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[TCP]: Introduce tcp_hdrlen() and tcp_optlen()Arnaldo Carvalho de Melo
The ip_hdrlen() buddy, created to reduce the number of skb->h.th-> uses and to avoid the longer, open coded equivalent. Ditched a no-op in bnx2 in the process. I wonder if we should have a BUG_ON(skb->h.th->doff < 5) in tcp_optlen()... Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce icmp_hdr(), remove skb->h.icmphArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce udp_hdr(), remove skb->h.uhArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce igmp_hdr() & friends, remove skb->h.igmphArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[ICMP6]: Introduce icmp6_hdr()Arnaldo Carvalho de Melo
For consistency with all the other skb->h.raw accessors. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SCTP]: Introduce sctp_hdr()Arnaldo Carvalho de Melo
For consistency with all the other skb->h.raw accessors. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_set_transport_headerArnaldo Carvalho de Melo
For the cases where the transport header is being set to a offset from skb->data. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_transport_offset()Arnaldo Carvalho de Melo
For the quite common 'skb->h.raw - skb->data' sequence. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_reset_transport_header(skb)Arnaldo Carvalho de Melo
For the common, open coded 'skb->h.raw = skb->data' operation, so that we can later turn skb->h.raw into a offset, reducing the size of struct sk_buff in 64bit land while possibly keeping it as a pointer on 32bit. This one touches just the most simple cases: skb->h.raw = skb->data; skb->h.raw = {skb_push|[__]skb_pull}() The next ones will handle the slightly more "complex" cases. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce ipv6_hdr(), remove skb->nh.ipv6hArnaldo Carvalho de Melo
Now the skb->nh union has just one member, .raw, i.e. it is just like the skb->mac union, strange, no? I'm just leaving it like that till the transport layer is done with, when we'll rename skb->mac.raw to skb->mac_header (or ->mac_header_offset?), ditto for ->{h,nh}. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce arp_hdr(), remove skb->nh.arphArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce ip_hdr(), remove skb->nh.iphArnaldo Carvalho de Melo
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_set_network_headerArnaldo Carvalho de Melo
For the cases where the network header is being set to a offset from skb->data. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_network_header()Arnaldo Carvalho de Melo
For the places where we need a pointer to the network header, it is still legal to touch skb->nh.raw directly if just adding to, subtracting from or setting it to another layer header. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_network_offset()Arnaldo Carvalho de Melo
For the quite common 'skb->nh.raw - skb->data' sequence. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_reset_network_header(skb)Arnaldo Carvalho de Melo
For the common, open coded 'skb->nh.raw = skb->data' operation, so that we can later turn skb->nh.raw into a offset, reducing the size of struct sk_buff in 64bit land while possibly keeping it as a pointer on 32bit. This one touches just the most simple case, next will handle the slightly more "complex" cases. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[PPPOE]: Introduce pppoe_hdr()Arnaldo Carvalho de Melo
For consistency with all the other skb->nh.raw accessors. Also do some really obvious simplifications in pppoe_recvmsg, well the kfree_skb one is not so obvious, but free() and kfree() have the same behaviour (hint :-) ). Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_mac_header()Arnaldo Carvalho de Melo
For the places where we need a pointer to the mac header, it is still legal to touch skb->mac.raw directly if just adding to, subtracting from or setting it to another layer header. This one also converts some more cases to skb_reset_mac_header() that my regex missed as it had no spaces before nor after '=', ugh. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_set_mac_header()Arnaldo Carvalho de Melo
For the cases where we want to set skb->mac.raw to an offset from skb->data. Simple cases first, the memmove ones and specially pktgen will be left for later. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_reset_mac_header(skb)Arnaldo Carvalho de Melo
For the common, open coded 'skb->mac.raw = skb->data' operation, so that we can later turn skb->mac.raw into a offset, reducing the size of struct sk_buff in 64bit land while possibly keeping it as a pointer on 32bit. This one touches just the most simple case, next will handle the slightly more "complex" cases. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[NET]: Replace CONFIG_NET_DEBUG with sysctl.Stephen Hemminger
Covert network warning messages from a compile time to runtime choice. Removes kernel config option and replaces it with new /proc/sys/net/core/warnings. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[UDP]: Clean up UDP-Lite receive checksumHerbert Xu
This patch eliminates some duplicate code for the verification of receive checksums between UDP-Lite and UDP. It does this by introducing __skb_checksum_complete_head which is identical to __skb_checksum_complete_head apart from the fact that it takes a length parameter rather than computing the first skb->len bytes. As a result UDP-Lite will be able to use hardware checksum offload for packets which do not use partial coverage checksums. It also means that UDP-Lite loopback no longer does unnecessary checksum verification. If any NICs start support UDP-Lite this would also start working automatically. This patch removes the assumption that msg_flags has MSG_TRUNC clear upon entry in recvmsg. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[NETLINK]: Limit NLMSG_GOODSIZE to 8K.David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[IPV6] ADDRCONF: Optimistic Duplicate Address Detection (RFC 4429) Support.Neil Horman
Nominally an autoconfigured IPv6 address is added to an interface in the Tentative state (as per RFC 2462). Addresses in this state remain in this state while the Duplicate Address Detection process operates on them to determine their uniqueness on the network. During this period, these tentative addresses may not be used for communication, increasing the time before a node may be able to communicate on a network. Using Optimistic Duplicate Address Detection, autoconfigured addresses may be used immediately for communication on the network, as long as certain rules are followed to avoid conflicts with other nodes during the Duplicate Address Detection process. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[NET]: convert network timestamps to ktime_tEric Dumazet
We currently use a special structure (struct skb_timeval) and plain 'struct timeval' to store packet timestamps in sk_buffs and struct sock. This has some drawbacks : - Fixed resolution of micro second. - Waste of space on 64bit platforms where sizeof(struct timeval)=16 I suggest using ktime_t that is a nice abstraction of high resolution time services, currently capable of nanosecond resolution. As sizeof(ktime_t) is 8 bytes, using ktime_t in 'struct sock' permits a 8 byte shrink of this structure on 64bit architectures. Some other structures also benefit from this size reduction (struct ipq in ipv4/ip_fragment.c, struct frag_queue in ipv6/reassembly.c, ...) Once this ktime infrastructure adopted, we can more easily provide nanosecond resolution on top of it. (ioctl SIOCGSTAMPNS and/or SO_TIMESTAMPNS/SCM_TIMESTAMPNS) Note : this patch includes a bug correction in compat_sock_get_timestamp() where a "err = 0;" was missing (so this syscall returned -ENOENT instead of 0) Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> CC: Stephen Hemminger <shemminger@linux-foundation.org> CC: John find <linux.kernel@free.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[TCP]: Add two new spurious RTO responses to FRTOIlpo Järvinen
New sysctl tcp_frto_response is added to select amongst these responses: - Rate halving based; reuses CA_CWR state (default) - Very conservative; used to be the only one available (=1) - Undo cwr; undoes ssthresh and cwnd reductions (=2) The response with rate halving requires a new parameter to tcp_enter_cwr because FRTO has already reduced ssthresh and doing a second reduction there has to be prevented. In addition, to keep things nice on 80 cols screen, a local variable was added. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[TCP]: Make snd_cwnd_clamp a u32.David S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[TCP]: Keep copied_seq, rcv_wup and rcv_next together.Eric Dumazet
I noticed in oprofile study a cache miss in tcp_rcv_established() to read copied_seq. ffffffff80400a80 <tcp_rcv_established>: /* tcp_rcv_established total: 4034293   2.0400 */  55493  0.0281 :ffffffff80400bc9:   mov    0x4c8(%r12),%eax copied_seq 543103  0.2746 :ffffffff80400bd1:   cmp    0x3e0(%r12),%eax   rcv_nxt     if (tp->copied_seq == tp->rcv_nxt &&         len - tcp_header_len <= tp->ucopy.len) { In this function, the cache line 0x4c0 -> 0x500 is used only for this reading 'copied_seq' field. rcv_wup and copied_seq should be next to rcv_nxt field, to lower number of active cache lines in hot paths. (tcp_rcv_established(), tcp_poll(), ...) As you suggested, I changed tcp_create_openreq_child() so that these fields are changed together, to avoid adding a new store buffer stall. Patch is 64bit friendly (no new hole because of alignment constraints) Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[TCP]: Add RFC3742 Limited Slow-Start, controlled by variable ↵John Heffner
sysctl_tcp_max_ssthresh. Signed-off-by: John Heffner <jheffner@psc.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-24Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds
* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6: [BNX2]: Fix occasional NETDEV WATCHDOG on 5709. [IPV6]: Disallow RH0 by default. [XFRM]: beet: fix pseudo header length value [TCP]: Congestion control initialization.
2007-04-24[IPV6]: Disallow RH0 by default.YOSHIFUJI Hideaki
A security issue is emerging. Disallow Routing Header Type 0 by default as we have been doing for IPv4. Note: We allow RH2 by default because it is harmless. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-24Taskstats fix the structure members alignment issueBalbir Singh
We broke the the alignment of members of taskstats to the 8 byte boundary with the CSA patches. In the current kernel, the taskstats structure is not suitable for use by 32 bit applications in a 64 bit kernel. On x86_64 Offsets of taskstats' members (64 bit kernel, 64 bit application) @taskstats'offsetof[@taskstats'indices] = ( 0, # version 4, # ac_exitcode 8, # ac_flag 9, # ac_nice 16, # cpu_count 24, # cpu_delay_total 32, # blkio_count 40, # blkio_delay_total 48, # swapin_count 56, # swapin_delay_total 64, # cpu_run_real_total 72, # cpu_run_virtual_total 80, # ac_comm 112, # ac_sched 113, # ac_pad 116, # ac_uid 120, # ac_gid 124, # ac_pid 128, # ac_ppid 132, # ac_btime 136, # ac_etime 144, # ac_utime 152, # ac_stime 160, # ac_minflt 168, # ac_majflt 176, # coremem 184, # virtmem 192, # hiwater_rss 200, # hiwater_vm 208, # read_char 216, # write_char 224, # read_syscalls 232, # write_syscalls 240, # read_bytes 248, # write_bytes 256, # cancelled_write_bytes ); Offsets of taskstats' members (64 bit kernel, 32 bit application) @taskstats'offsetof[@taskstats'indices] = ( 0, # version 4, # ac_exitcode 8, # ac_flag 9, # ac_nice 12, # cpu_count 20, # cpu_delay_total 28, # blkio_count 36, # blkio_delay_total 44, # swapin_count 52, # swapin_delay_total 60, # cpu_run_real_total 68, # cpu_run_virtual_total 76, # ac_comm 108, # ac_sched 109, # ac_pad 112, # ac_uid 116, # ac_gid 120, # ac_pid 124, # ac_ppid 128, # ac_btime 132, # ac_etime 140, # ac_utime 148, # ac_stime 156, # ac_minflt 164, # ac_majflt 172, # coremem 180, # virtmem 188, # hiwater_rss 196, # hiwater_vm 204, # read_char 212, # write_char 220, # read_syscalls 228, # write_syscalls 236, # read_bytes 244, # write_bytes 252, # cancelled_write_bytes ); This is one way to solve the problem without re-arranging structure members is to pack the structure. The patch adds an __attribute__((aligned(8))) to the taskstats structure members so that 32 bit applications using taskstats can work with a 64 bit kernel. Using __attribute__((packed)) would break the 64 bit alignment of members. The fix was tested on x86_64. After the fix, we got Offsets of taskstats' members (64 bit kernel, 64 bit application) @taskstats'offsetof[@taskstats'indices] = ( 0, # version 4, # ac_exitcode 8, # ac_flag 9, # ac_nice 16, # cpu_count 24, # cpu_delay_total 32, # blkio_count 40, # blkio_delay_total 48, # swapin_count 56, # swapin_delay_total 64, # cpu_run_real_total 72, # cpu_run_virtual_total 80, # ac_comm 112, # ac_sched 113, # ac_pad 120, # ac_uid 124, # ac_gid 128, # ac_pid 132, # ac_ppid 136, # ac_btime 144, # ac_etime 152, # ac_utime 160, # ac_stime 168, # ac_minflt 176, # ac_majflt 184, # coremem 192, # virtmem 200, # hiwater_rss 208, # hiwater_vm 216, # read_char 224, # write_char 232, # read_syscalls 240, # write_syscalls 248, # read_bytes 256, # write_bytes 264, # cancelled_write_bytes ); Offsets of taskstats' members (64 bit kernel, 32 bit application) @taskstats'offsetof[@taskstats'indices] = ( 0, # version 4, # ac_exitcode 8, # ac_flag 9, # ac_nice 16, # cpu_count 24, # cpu_delay_total 32, # blkio_count 40, # blkio_delay_total 48, # swapin_count 56, # swapin_delay_total 64, # cpu_run_real_total 72, # cpu_run_virtual_total 80, # ac_comm 112, # ac_sched 113, # ac_pad 120, # ac_uid 124, # ac_gid 128, # ac_pid 132, # ac_ppid 136, # ac_btime 144, # ac_etime 152, # ac_utime 160, # ac_stime 168, # ac_minflt 176, # ac_majflt 184, # coremem 192, # virtmem 200, # hiwater_rss 208, # hiwater_vm 216, # read_char 224, # write_char 232, # read_syscalls 240, # write_syscalls 248, # read_bytes 256, # write_bytes 264, # cancelled_write_bytes ); Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Jay Lan <jlan@engr.sgi.com> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>