litmus-rt.git - The LITMUS^RT kernel.

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author	Eric Dumazet <eric.dumazet@gmail.com>	2009-07-03 07:23:02 -0400
committer	Ingo Molnar <mingo@elte.hu>	2009-07-03 08:42:59 -0400
commit	67d7178f8fc64b7f68d7dd8a1b21dfa0d42c220c (patch)
tree	d14adbf73d928b9c954d8ade1a3df8c61183fd95 /mm/page_alloc.c
parent	8e049ef054f1cc765f05f13e1396bb9a17c19e66 (diff)

x86: atomic64: Improve atomic64_read()

Optimize atomic64_read() as a special open-coded cmpxchg8b variant. This generates nicer code: arch/x86/lib/atomic64_32.o: text data bss dec hex filename 435 0 0 435 1b3 atomic64_32.o.before 431 0 0 431 1af atomic64_32.o.after md5: bd8ab95e69c93518578bfaf0ea3be4d9 atomic64_32.o.before.asm 2bdfd4bd1f6b7b61b7fc127aef90ce3b atomic64_32.o.after.asm Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>

Diffstat (limited to 'mm/page_alloc.c')

0 files changed, 0 insertions, 0 deletions

/* * IPv6 Syncookies implementation for the Linux kernel * * Authors: * Glenn Griffin <ggriffin.kernel@gmail.com> * * Based on IPv4 implementation by Andi Kleen * linux/net/ipv4/syncookies.c * * 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. * */ #include <linux/tcp.h> #include <linux/random.h> #include <linux/cryptohash.h> #include <linux/kernel.h> #include <net/ipv6.h> #include <net/tcp.h> #define COOKIEBITS 24 /* Upper bits store count */ #define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1) /* Table must be sorted. */ static __u16 const msstab[] = { 64, 512, 536, 1280 - 60, 1480 - 60, 1500 - 60, 4460 - 60, 9000 - 60, }; /* * This (misnamed) value is the age of syncookie which is permitted. * Its ideal value should be dependent on TCP_TIMEOUT_INIT and * sysctl_tcp_retries1. It's a rather complicated formula (exponential * backoff) to compute at runtime so it's currently hardcoded here. */ #define COUNTER_TRIES 4 static inline struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb, struct request_sock *req, struct dst_entry *dst) { struct inet_connection_sock *icsk = inet_csk(sk); struct sock *child; child = icsk->icsk_af_ops->syn_recv_sock(sk, skb, req, dst); if (child) inet_csk_reqsk_queue_add(sk, req, child); else reqsk_free(req); return child; } static DEFINE_PER_CPU(__u32 [16 + 5 + SHA_WORKSPACE_WORDS], ipv6_cookie_scratch); static u32 cookie_hash(const struct in6_addr *saddr, const struct in6_addr *daddr, __be16 sport, __be16 dport, u32 count, int c) { __u32 *tmp = __get_cpu_var(ipv6_cookie_scratch); /* * we have 320 bits of information to hash, copy in the remaining * 192 bits required for sha_transform, from the syncookie_secret * and overwrite the digest with the secret */ memcpy(tmp + 10, syncookie_secret[c], 44); memcpy(tmp, saddr, 16); memcpy(tmp + 4, daddr, 16); tmp[8] = ((__force u32)sport << 16) + (__force u32)dport; tmp[9] = count; sha_transform(tmp + 16, (__u8 *)tmp, tmp + 16 + 5); return tmp[17]; } static __u32 secure_tcp_syn_cookie(const struct in6_addr *saddr, const struct in6_addr *daddr, __be16 sport, __be16 dport, __u32 sseq, __u32 count, __u32 data) { return (cookie_hash(saddr, daddr, sport, dport, 0, 0) + sseq + (count << COOKIEBITS) + ((cookie_hash(saddr, daddr, sport, dport, count, 1) + data) & COOKIEMASK)); } static __u32 check_tcp_syn_cookie(__u32 cookie, const struct in6_addr *saddr, const struct in6_addr *daddr, __be16 sport, __be16 dport, __u32 sseq, __u32 count, __u32 maxdiff) { __u32 diff; cookie -= cookie_hash(saddr, daddr, sport, dport, 0, 0) + sseq; diff = (count - (cookie >> COOKIEBITS)) & ((__u32) -1 >> COOKIEBITS); if (diff >= maxdiff) return (__u32)-1; return (cookie - cookie_hash(saddr, daddr, sport, dport, count - diff, 1)) & COOKIEMASK; } u32 __cookie_v6_init_sequence(const struct ipv6hdr *iph, const struct tcphdr *th, __u16 *mssp) { int mssind; const __u16 mss = *mssp; for (mssind = ARRAY_SIZE(msstab) - 1; mssind ; mssind--) if (mss >= msstab[mssind]) break; *mssp = msstab[mssind]; return secure_tcp_syn_cookie(&iph->saddr, &iph->daddr, th->source, th->dest, ntohl(th->seq), jiffies / (HZ * 60), mssind); } EXPORT_SYMBOL_GPL(__cookie_v6_init_sequence); __u32 cookie_v6_init_sequence(struct sock *sk, const struct sk_buff *skb, __u16 *mssp) { const struct ipv6hdr *iph = ipv6_hdr(skb); const struct tcphdr *th = tcp_hdr(skb); tcp_synq_overflow(sk); NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESSENT); return __cookie_v6_init_sequence(iph, th, mssp); } int __cookie_v6_check(const struct ipv6hdr *iph, const struct tcphdr *th, __u32 cookie) { __u32 seq = ntohl(th->seq) - 1; __u32 mssind = check_tcp_syn_cookie(cookie, &iph->saddr, &iph->daddr, th->source, th->dest, seq, jiffies / (HZ * 60), COUNTER_TRIES); return mssind < ARRAY_SIZE(msstab) ? msstab[mssind] : 0; } EXPORT_SYMBOL_GPL(__cookie_v6_check); struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) { struct tcp_options_received tcp_opt; struct inet_request_sock *ireq; struct inet6_request_sock *ireq6; struct tcp_request_sock *treq; struct ipv6_pinfo *np = inet6_sk(sk); struct tcp_sock *tp = tcp_sk(sk); const struct tcphdr *th = tcp_hdr(skb); __u32 cookie = ntohl(th->ack_seq) - 1; struct sock *ret = sk; struct request_sock *req; int mss; struct dst_entry *dst; __u8 rcv_wscale; bool ecn_ok = false; if (!sysctl_tcp_syncookies || !th->ack || th->rst) goto out; if (tcp_synq_no_recent_overflow(sk) || (mss = __cookie_v6_check(ipv6_hdr(skb), th, cookie)) == 0) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED); goto out; } NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESRECV); /* check for timestamp cookie support */ memset(&tcp_opt, 0, sizeof(tcp_opt)); tcp_parse_options(skb, &tcp_opt, 0, NULL); if (!cookie_check_timestamp(&tcp_opt, sock_net(sk), &ecn_ok)) goto out; ret = NULL; req = inet6_reqsk_alloc(&tcp6_request_sock_ops); if (!req) goto out; ireq = inet_rsk(req); ireq6 = inet6_rsk(req); treq = tcp_rsk(req); treq->listener = NULL; if (security_inet_conn_request(sk, skb, req)) goto out_free; req->mss = mss; ireq->rmt_port = th->source; ireq->loc_port = th->dest; ireq6->rmt_addr = ipv6_hdr(skb)->saddr; ireq6->loc_addr = ipv6_hdr(skb)->daddr; if (ipv6_opt_accepted(sk, skb) || np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo || np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) { atomic_inc(&skb->users); ireq6->pktopts = skb; } ireq6->iif = sk->sk_bound_dev_if; /* So that link locals have meaning */ if (!sk->sk_bound_dev_if && ipv6_addr_type(&ireq6->rmt_addr) & IPV6_ADDR_LINKLOCAL) ireq6->iif = inet6_iif(skb); req->expires = 0UL; req->num_retrans = 0; ireq->ecn_ok = ecn_ok; ireq->snd_wscale = tcp_opt.snd_wscale; ireq->sack_ok = tcp_opt.sack_ok; ireq->wscale_ok = tcp_opt.wscale_ok; ireq->tstamp_ok = tcp_opt.saw_tstamp; req->ts_recent = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0; treq->snt_synack = tcp_opt.saw_tstamp ? tcp_opt.rcv_tsecr : 0; treq->rcv_isn = ntohl(th->seq) - 1; treq->snt_isn = cookie; /* * We need to lookup the dst_entry to get the correct window size. * This is taken from tcp_v6_syn_recv_sock. Somebody please enlighten * me if there is a preferred way. */ { struct in6_addr *final_p, final; struct flowi6 fl6; memset(&fl6, 0, sizeof(fl6)); fl6.flowi6_proto = IPPROTO_TCP; fl6.daddr = ireq6->rmt_addr; final_p = fl6_update_dst(&fl6, np->opt, &final); fl6.saddr = ireq6->loc_addr; fl6.flowi6_oif = sk->sk_bound_dev_if; fl6.flowi6_mark = sk->sk_mark; fl6.fl6_dport = inet_rsk(req)->rmt_port; fl6.fl6_sport = inet_sk(sk)->inet_sport; security_req_classify_flow(req, flowi6_to_flowi(&fl6)); dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false); if (IS_ERR(dst)) goto out_free; } req->window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW); tcp_select_initial_window(tcp_full_space(sk), req->mss, &req->rcv_wnd, &req->window_clamp, ireq->wscale_ok, &rcv_wscale, dst_metric(dst, RTAX_INITRWND)); ireq->rcv_wscale = rcv_wscale; ret = get_cookie_sock(sk, skb, req, dst); out: return ret; out_free: reqsk_free(req); return NULL; }


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