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![Eric Dumazet](/assets/img/avatar_default.png)
syzbot reported a race around qdisc->qdisc_sleeping [1]
It is time we add proper annotations to reads and writes to/from
qdisc->qdisc_sleeping.
[1]
BUG: KCSAN: data-race in dev_graft_qdisc / qdisc_lookup_rcu
read to 0xffff8881286fc618 of 8 bytes by task 6928 on cpu 1:
qdisc_lookup_rcu+0x192/0x2c0 net/sched/sch_api.c:331
__tcf_qdisc_find+0x74/0x3c0 net/sched/cls_api.c:1174
tc_get_tfilter+0x18f/0x990 net/sched/cls_api.c:2547
rtnetlink_rcv_msg+0x7af/0x8c0 net/core/rtnetlink.c:6386
netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2546
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6413
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x56f/0x640 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x665/0x770 net/netlink/af_netlink.c:1913
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0x375/0x4c0 net/socket.c:2503
___sys_sendmsg net/socket.c:2557 [inline]
__sys_sendmsg+0x1e3/0x270 net/socket.c:2586
__do_sys_sendmsg net/socket.c:2595 [inline]
__se_sys_sendmsg net/socket.c:2593 [inline]
__x64_sys_sendmsg+0x46/0x50 net/socket.c:2593
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
write to 0xffff8881286fc618 of 8 bytes by task 6912 on cpu 0:
dev_graft_qdisc+0x4f/0x80 net/sched/sch_generic.c:1115
qdisc_graft+0x7d0/0xb60 net/sched/sch_api.c:1103
tc_modify_qdisc+0x712/0xf10 net/sched/sch_api.c:1693
rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6395
netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2546
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6413
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x56f/0x640 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x665/0x770 net/netlink/af_netlink.c:1913
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0x375/0x4c0 net/socket.c:2503
___sys_sendmsg net/socket.c:2557 [inline]
__sys_sendmsg+0x1e3/0x270 net/socket.c:2586
__do_sys_sendmsg net/socket.c:2595 [inline]
__se_sys_sendmsg net/socket.c:2593 [inline]
__x64_sys_sendmsg+0x46/0x50 net/socket.c:2593
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6912 Comm: syz-executor.5 Not tainted 6.4.0-rc3-syzkaller-00190-g0d85b27b0cc6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/16/2023
Fixes: 3a7d0d07a3
("net: sched: extend Qdisc with rcu")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Vlad Buslov <vladbu@nvidia.com>
Acked-by: Jamal Hadi Salim<jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
939 lines
22 KiB
C
939 lines
22 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* net/sched/sch_sfq.c Stochastic Fairness Queueing discipline.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/jiffies.h>
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#include <linux/string.h>
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#include <linux/in.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/skbuff.h>
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#include <linux/siphash.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <net/netlink.h>
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#include <net/pkt_sched.h>
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#include <net/pkt_cls.h>
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#include <net/red.h>
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/* Stochastic Fairness Queuing algorithm.
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=======================================
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Source:
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Paul E. McKenney "Stochastic Fairness Queuing",
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IEEE INFOCOMM'90 Proceedings, San Francisco, 1990.
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Paul E. McKenney "Stochastic Fairness Queuing",
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"Interworking: Research and Experience", v.2, 1991, p.113-131.
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See also:
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M. Shreedhar and George Varghese "Efficient Fair
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Queuing using Deficit Round Robin", Proc. SIGCOMM 95.
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This is not the thing that is usually called (W)FQ nowadays.
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It does not use any timestamp mechanism, but instead
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processes queues in round-robin order.
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ADVANTAGE:
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- It is very cheap. Both CPU and memory requirements are minimal.
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DRAWBACKS:
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- "Stochastic" -> It is not 100% fair.
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When hash collisions occur, several flows are considered as one.
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- "Round-robin" -> It introduces larger delays than virtual clock
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based schemes, and should not be used for isolating interactive
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traffic from non-interactive. It means, that this scheduler
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should be used as leaf of CBQ or P3, which put interactive traffic
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to higher priority band.
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We still need true WFQ for top level CSZ, but using WFQ
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for the best effort traffic is absolutely pointless:
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SFQ is superior for this purpose.
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IMPLEMENTATION:
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This implementation limits :
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- maximal queue length per flow to 127 packets.
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- max mtu to 2^18-1;
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- max 65408 flows,
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- number of hash buckets to 65536.
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It is easy to increase these values, but not in flight. */
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#define SFQ_MAX_DEPTH 127 /* max number of packets per flow */
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#define SFQ_DEFAULT_FLOWS 128
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#define SFQ_MAX_FLOWS (0x10000 - SFQ_MAX_DEPTH - 1) /* max number of flows */
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#define SFQ_EMPTY_SLOT 0xffff
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#define SFQ_DEFAULT_HASH_DIVISOR 1024
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/* We use 16 bits to store allot, and want to handle packets up to 64K
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* Scale allot by 8 (1<<3) so that no overflow occurs.
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*/
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#define SFQ_ALLOT_SHIFT 3
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#define SFQ_ALLOT_SIZE(X) DIV_ROUND_UP(X, 1 << SFQ_ALLOT_SHIFT)
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/* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */
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typedef u16 sfq_index;
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/*
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* We dont use pointers to save space.
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* Small indexes [0 ... SFQ_MAX_FLOWS - 1] are 'pointers' to slots[] array
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* while following values [SFQ_MAX_FLOWS ... SFQ_MAX_FLOWS + SFQ_MAX_DEPTH]
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* are 'pointers' to dep[] array
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*/
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struct sfq_head {
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sfq_index next;
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sfq_index prev;
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};
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struct sfq_slot {
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struct sk_buff *skblist_next;
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struct sk_buff *skblist_prev;
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sfq_index qlen; /* number of skbs in skblist */
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sfq_index next; /* next slot in sfq RR chain */
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struct sfq_head dep; /* anchor in dep[] chains */
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unsigned short hash; /* hash value (index in ht[]) */
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short allot; /* credit for this slot */
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unsigned int backlog;
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struct red_vars vars;
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};
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struct sfq_sched_data {
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/* frequently used fields */
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int limit; /* limit of total number of packets in this qdisc */
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unsigned int divisor; /* number of slots in hash table */
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u8 headdrop;
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u8 maxdepth; /* limit of packets per flow */
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siphash_key_t perturbation;
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u8 cur_depth; /* depth of longest slot */
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u8 flags;
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unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */
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struct tcf_proto __rcu *filter_list;
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struct tcf_block *block;
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sfq_index *ht; /* Hash table ('divisor' slots) */
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struct sfq_slot *slots; /* Flows table ('maxflows' entries) */
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struct red_parms *red_parms;
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struct tc_sfqred_stats stats;
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struct sfq_slot *tail; /* current slot in round */
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struct sfq_head dep[SFQ_MAX_DEPTH + 1];
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/* Linked lists of slots, indexed by depth
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* dep[0] : list of unused flows
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* dep[1] : list of flows with 1 packet
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* dep[X] : list of flows with X packets
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*/
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unsigned int maxflows; /* number of flows in flows array */
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int perturb_period;
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unsigned int quantum; /* Allotment per round: MUST BE >= MTU */
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struct timer_list perturb_timer;
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struct Qdisc *sch;
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};
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/*
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* sfq_head are either in a sfq_slot or in dep[] array
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*/
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static inline struct sfq_head *sfq_dep_head(struct sfq_sched_data *q, sfq_index val)
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{
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if (val < SFQ_MAX_FLOWS)
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return &q->slots[val].dep;
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return &q->dep[val - SFQ_MAX_FLOWS];
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}
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static unsigned int sfq_hash(const struct sfq_sched_data *q,
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const struct sk_buff *skb)
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{
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return skb_get_hash_perturb(skb, &q->perturbation) & (q->divisor - 1);
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}
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static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
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int *qerr)
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{
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struct sfq_sched_data *q = qdisc_priv(sch);
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struct tcf_result res;
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struct tcf_proto *fl;
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int result;
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if (TC_H_MAJ(skb->priority) == sch->handle &&
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TC_H_MIN(skb->priority) > 0 &&
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TC_H_MIN(skb->priority) <= q->divisor)
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return TC_H_MIN(skb->priority);
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fl = rcu_dereference_bh(q->filter_list);
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if (!fl)
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return sfq_hash(q, skb) + 1;
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*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
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result = tcf_classify(skb, NULL, fl, &res, false);
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if (result >= 0) {
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#ifdef CONFIG_NET_CLS_ACT
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switch (result) {
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case TC_ACT_STOLEN:
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case TC_ACT_QUEUED:
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case TC_ACT_TRAP:
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*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
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fallthrough;
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case TC_ACT_SHOT:
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return 0;
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}
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#endif
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if (TC_H_MIN(res.classid) <= q->divisor)
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return TC_H_MIN(res.classid);
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}
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return 0;
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}
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/*
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* x : slot number [0 .. SFQ_MAX_FLOWS - 1]
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*/
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static inline void sfq_link(struct sfq_sched_data *q, sfq_index x)
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{
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sfq_index p, n;
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struct sfq_slot *slot = &q->slots[x];
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int qlen = slot->qlen;
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p = qlen + SFQ_MAX_FLOWS;
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n = q->dep[qlen].next;
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slot->dep.next = n;
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slot->dep.prev = p;
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q->dep[qlen].next = x; /* sfq_dep_head(q, p)->next = x */
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sfq_dep_head(q, n)->prev = x;
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}
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#define sfq_unlink(q, x, n, p) \
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do { \
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n = q->slots[x].dep.next; \
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p = q->slots[x].dep.prev; \
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sfq_dep_head(q, p)->next = n; \
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sfq_dep_head(q, n)->prev = p; \
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} while (0)
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static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x)
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{
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sfq_index p, n;
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int d;
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sfq_unlink(q, x, n, p);
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d = q->slots[x].qlen--;
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if (n == p && q->cur_depth == d)
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q->cur_depth--;
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sfq_link(q, x);
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}
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static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x)
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{
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sfq_index p, n;
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int d;
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sfq_unlink(q, x, n, p);
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d = ++q->slots[x].qlen;
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if (q->cur_depth < d)
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q->cur_depth = d;
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sfq_link(q, x);
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}
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/* helper functions : might be changed when/if skb use a standard list_head */
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/* remove one skb from tail of slot queue */
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static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot)
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{
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struct sk_buff *skb = slot->skblist_prev;
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slot->skblist_prev = skb->prev;
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skb->prev->next = (struct sk_buff *)slot;
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skb->next = skb->prev = NULL;
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return skb;
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}
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/* remove one skb from head of slot queue */
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static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot)
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{
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struct sk_buff *skb = slot->skblist_next;
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slot->skblist_next = skb->next;
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skb->next->prev = (struct sk_buff *)slot;
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skb->next = skb->prev = NULL;
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return skb;
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}
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static inline void slot_queue_init(struct sfq_slot *slot)
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{
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memset(slot, 0, sizeof(*slot));
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slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot;
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}
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/* add skb to slot queue (tail add) */
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static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb)
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{
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skb->prev = slot->skblist_prev;
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skb->next = (struct sk_buff *)slot;
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slot->skblist_prev->next = skb;
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slot->skblist_prev = skb;
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}
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static unsigned int sfq_drop(struct Qdisc *sch, struct sk_buff **to_free)
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{
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struct sfq_sched_data *q = qdisc_priv(sch);
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sfq_index x, d = q->cur_depth;
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struct sk_buff *skb;
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unsigned int len;
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struct sfq_slot *slot;
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/* Queue is full! Find the longest slot and drop tail packet from it */
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if (d > 1) {
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x = q->dep[d].next;
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slot = &q->slots[x];
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drop:
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skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot);
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len = qdisc_pkt_len(skb);
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slot->backlog -= len;
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sfq_dec(q, x);
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sch->q.qlen--;
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qdisc_qstats_backlog_dec(sch, skb);
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qdisc_drop(skb, sch, to_free);
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return len;
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}
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if (d == 1) {
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/* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */
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x = q->tail->next;
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slot = &q->slots[x];
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q->tail->next = slot->next;
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q->ht[slot->hash] = SFQ_EMPTY_SLOT;
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goto drop;
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}
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return 0;
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}
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/* Is ECN parameter configured */
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static int sfq_prob_mark(const struct sfq_sched_data *q)
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{
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return q->flags & TC_RED_ECN;
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}
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/* Should packets over max threshold just be marked */
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static int sfq_hard_mark(const struct sfq_sched_data *q)
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{
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return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN;
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}
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|
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static int sfq_headdrop(const struct sfq_sched_data *q)
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{
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return q->headdrop;
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}
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|
|
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static int
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sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
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{
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struct sfq_sched_data *q = qdisc_priv(sch);
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unsigned int hash, dropped;
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sfq_index x, qlen;
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struct sfq_slot *slot;
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int ret;
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struct sk_buff *head;
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int delta;
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hash = sfq_classify(skb, sch, &ret);
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if (hash == 0) {
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if (ret & __NET_XMIT_BYPASS)
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qdisc_qstats_drop(sch);
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__qdisc_drop(skb, to_free);
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return ret;
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}
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hash--;
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x = q->ht[hash];
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slot = &q->slots[x];
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if (x == SFQ_EMPTY_SLOT) {
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x = q->dep[0].next; /* get a free slot */
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if (x >= SFQ_MAX_FLOWS)
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return qdisc_drop(skb, sch, to_free);
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q->ht[hash] = x;
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slot = &q->slots[x];
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slot->hash = hash;
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slot->backlog = 0; /* should already be 0 anyway... */
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red_set_vars(&slot->vars);
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goto enqueue;
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}
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if (q->red_parms) {
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slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms,
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&slot->vars,
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slot->backlog);
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switch (red_action(q->red_parms,
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&slot->vars,
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slot->vars.qavg)) {
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case RED_DONT_MARK:
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break;
|
|
|
|
case RED_PROB_MARK:
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qdisc_qstats_overlimit(sch);
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if (sfq_prob_mark(q)) {
|
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/* We know we have at least one packet in queue */
|
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if (sfq_headdrop(q) &&
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INET_ECN_set_ce(slot->skblist_next)) {
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q->stats.prob_mark_head++;
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break;
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}
|
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if (INET_ECN_set_ce(skb)) {
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q->stats.prob_mark++;
|
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break;
|
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}
|
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}
|
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q->stats.prob_drop++;
|
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goto congestion_drop;
|
|
|
|
case RED_HARD_MARK:
|
|
qdisc_qstats_overlimit(sch);
|
|
if (sfq_hard_mark(q)) {
|
|
/* We know we have at least one packet in queue */
|
|
if (sfq_headdrop(q) &&
|
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INET_ECN_set_ce(slot->skblist_next)) {
|
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q->stats.forced_mark_head++;
|
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break;
|
|
}
|
|
if (INET_ECN_set_ce(skb)) {
|
|
q->stats.forced_mark++;
|
|
break;
|
|
}
|
|
}
|
|
q->stats.forced_drop++;
|
|
goto congestion_drop;
|
|
}
|
|
}
|
|
|
|
if (slot->qlen >= q->maxdepth) {
|
|
congestion_drop:
|
|
if (!sfq_headdrop(q))
|
|
return qdisc_drop(skb, sch, to_free);
|
|
|
|
/* We know we have at least one packet in queue */
|
|
head = slot_dequeue_head(slot);
|
|
delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb);
|
|
sch->qstats.backlog -= delta;
|
|
slot->backlog -= delta;
|
|
qdisc_drop(head, sch, to_free);
|
|
|
|
slot_queue_add(slot, skb);
|
|
qdisc_tree_reduce_backlog(sch, 0, delta);
|
|
return NET_XMIT_CN;
|
|
}
|
|
|
|
enqueue:
|
|
qdisc_qstats_backlog_inc(sch, skb);
|
|
slot->backlog += qdisc_pkt_len(skb);
|
|
slot_queue_add(slot, skb);
|
|
sfq_inc(q, x);
|
|
if (slot->qlen == 1) { /* The flow is new */
|
|
if (q->tail == NULL) { /* It is the first flow */
|
|
slot->next = x;
|
|
} else {
|
|
slot->next = q->tail->next;
|
|
q->tail->next = x;
|
|
}
|
|
/* We put this flow at the end of our flow list.
|
|
* This might sound unfair for a new flow to wait after old ones,
|
|
* but we could endup servicing new flows only, and freeze old ones.
|
|
*/
|
|
q->tail = slot;
|
|
/* We could use a bigger initial quantum for new flows */
|
|
slot->allot = q->scaled_quantum;
|
|
}
|
|
if (++sch->q.qlen <= q->limit)
|
|
return NET_XMIT_SUCCESS;
|
|
|
|
qlen = slot->qlen;
|
|
dropped = sfq_drop(sch, to_free);
|
|
/* Return Congestion Notification only if we dropped a packet
|
|
* from this flow.
|
|
*/
|
|
if (qlen != slot->qlen) {
|
|
qdisc_tree_reduce_backlog(sch, 0, dropped - qdisc_pkt_len(skb));
|
|
return NET_XMIT_CN;
|
|
}
|
|
|
|
/* As we dropped a packet, better let upper stack know this */
|
|
qdisc_tree_reduce_backlog(sch, 1, dropped);
|
|
return NET_XMIT_SUCCESS;
|
|
}
|
|
|
|
static struct sk_buff *
|
|
sfq_dequeue(struct Qdisc *sch)
|
|
{
|
|
struct sfq_sched_data *q = qdisc_priv(sch);
|
|
struct sk_buff *skb;
|
|
sfq_index a, next_a;
|
|
struct sfq_slot *slot;
|
|
|
|
/* No active slots */
|
|
if (q->tail == NULL)
|
|
return NULL;
|
|
|
|
next_slot:
|
|
a = q->tail->next;
|
|
slot = &q->slots[a];
|
|
if (slot->allot <= 0) {
|
|
q->tail = slot;
|
|
slot->allot += q->scaled_quantum;
|
|
goto next_slot;
|
|
}
|
|
skb = slot_dequeue_head(slot);
|
|
sfq_dec(q, a);
|
|
qdisc_bstats_update(sch, skb);
|
|
sch->q.qlen--;
|
|
qdisc_qstats_backlog_dec(sch, skb);
|
|
slot->backlog -= qdisc_pkt_len(skb);
|
|
/* Is the slot empty? */
|
|
if (slot->qlen == 0) {
|
|
q->ht[slot->hash] = SFQ_EMPTY_SLOT;
|
|
next_a = slot->next;
|
|
if (a == next_a) {
|
|
q->tail = NULL; /* no more active slots */
|
|
return skb;
|
|
}
|
|
q->tail->next = next_a;
|
|
} else {
|
|
slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb));
|
|
}
|
|
return skb;
|
|
}
|
|
|
|
static void
|
|
sfq_reset(struct Qdisc *sch)
|
|
{
|
|
struct sk_buff *skb;
|
|
|
|
while ((skb = sfq_dequeue(sch)) != NULL)
|
|
rtnl_kfree_skbs(skb, skb);
|
|
}
|
|
|
|
/*
|
|
* When q->perturbation is changed, we rehash all queued skbs
|
|
* to avoid OOO (Out Of Order) effects.
|
|
* We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change
|
|
* counters.
|
|
*/
|
|
static void sfq_rehash(struct Qdisc *sch)
|
|
{
|
|
struct sfq_sched_data *q = qdisc_priv(sch);
|
|
struct sk_buff *skb;
|
|
int i;
|
|
struct sfq_slot *slot;
|
|
struct sk_buff_head list;
|
|
int dropped = 0;
|
|
unsigned int drop_len = 0;
|
|
|
|
__skb_queue_head_init(&list);
|
|
|
|
for (i = 0; i < q->maxflows; i++) {
|
|
slot = &q->slots[i];
|
|
if (!slot->qlen)
|
|
continue;
|
|
while (slot->qlen) {
|
|
skb = slot_dequeue_head(slot);
|
|
sfq_dec(q, i);
|
|
__skb_queue_tail(&list, skb);
|
|
}
|
|
slot->backlog = 0;
|
|
red_set_vars(&slot->vars);
|
|
q->ht[slot->hash] = SFQ_EMPTY_SLOT;
|
|
}
|
|
q->tail = NULL;
|
|
|
|
while ((skb = __skb_dequeue(&list)) != NULL) {
|
|
unsigned int hash = sfq_hash(q, skb);
|
|
sfq_index x = q->ht[hash];
|
|
|
|
slot = &q->slots[x];
|
|
if (x == SFQ_EMPTY_SLOT) {
|
|
x = q->dep[0].next; /* get a free slot */
|
|
if (x >= SFQ_MAX_FLOWS) {
|
|
drop:
|
|
qdisc_qstats_backlog_dec(sch, skb);
|
|
drop_len += qdisc_pkt_len(skb);
|
|
kfree_skb(skb);
|
|
dropped++;
|
|
continue;
|
|
}
|
|
q->ht[hash] = x;
|
|
slot = &q->slots[x];
|
|
slot->hash = hash;
|
|
}
|
|
if (slot->qlen >= q->maxdepth)
|
|
goto drop;
|
|
slot_queue_add(slot, skb);
|
|
if (q->red_parms)
|
|
slot->vars.qavg = red_calc_qavg(q->red_parms,
|
|
&slot->vars,
|
|
slot->backlog);
|
|
slot->backlog += qdisc_pkt_len(skb);
|
|
sfq_inc(q, x);
|
|
if (slot->qlen == 1) { /* The flow is new */
|
|
if (q->tail == NULL) { /* It is the first flow */
|
|
slot->next = x;
|
|
} else {
|
|
slot->next = q->tail->next;
|
|
q->tail->next = x;
|
|
}
|
|
q->tail = slot;
|
|
slot->allot = q->scaled_quantum;
|
|
}
|
|
}
|
|
sch->q.qlen -= dropped;
|
|
qdisc_tree_reduce_backlog(sch, dropped, drop_len);
|
|
}
|
|
|
|
static void sfq_perturbation(struct timer_list *t)
|
|
{
|
|
struct sfq_sched_data *q = from_timer(q, t, perturb_timer);
|
|
struct Qdisc *sch = q->sch;
|
|
spinlock_t *root_lock;
|
|
siphash_key_t nkey;
|
|
|
|
get_random_bytes(&nkey, sizeof(nkey));
|
|
rcu_read_lock();
|
|
root_lock = qdisc_lock(qdisc_root_sleeping(sch));
|
|
spin_lock(root_lock);
|
|
q->perturbation = nkey;
|
|
if (!q->filter_list && q->tail)
|
|
sfq_rehash(sch);
|
|
spin_unlock(root_lock);
|
|
|
|
if (q->perturb_period)
|
|
mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
|
|
{
|
|
struct sfq_sched_data *q = qdisc_priv(sch);
|
|
struct tc_sfq_qopt *ctl = nla_data(opt);
|
|
struct tc_sfq_qopt_v1 *ctl_v1 = NULL;
|
|
unsigned int qlen, dropped = 0;
|
|
struct red_parms *p = NULL;
|
|
struct sk_buff *to_free = NULL;
|
|
struct sk_buff *tail = NULL;
|
|
|
|
if (opt->nla_len < nla_attr_size(sizeof(*ctl)))
|
|
return -EINVAL;
|
|
if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1)))
|
|
ctl_v1 = nla_data(opt);
|
|
if (ctl->divisor &&
|
|
(!is_power_of_2(ctl->divisor) || ctl->divisor > 65536))
|
|
return -EINVAL;
|
|
|
|
/* slot->allot is a short, make sure quantum is not too big. */
|
|
if (ctl->quantum) {
|
|
unsigned int scaled = SFQ_ALLOT_SIZE(ctl->quantum);
|
|
|
|
if (scaled <= 0 || scaled > SHRT_MAX)
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (ctl_v1 && !red_check_params(ctl_v1->qth_min, ctl_v1->qth_max,
|
|
ctl_v1->Wlog, ctl_v1->Scell_log, NULL))
|
|
return -EINVAL;
|
|
if (ctl_v1 && ctl_v1->qth_min) {
|
|
p = kmalloc(sizeof(*p), GFP_KERNEL);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
}
|
|
sch_tree_lock(sch);
|
|
if (ctl->quantum) {
|
|
q->quantum = ctl->quantum;
|
|
q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
|
|
}
|
|
q->perturb_period = ctl->perturb_period * HZ;
|
|
if (ctl->flows)
|
|
q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS);
|
|
if (ctl->divisor) {
|
|
q->divisor = ctl->divisor;
|
|
q->maxflows = min_t(u32, q->maxflows, q->divisor);
|
|
}
|
|
if (ctl_v1) {
|
|
if (ctl_v1->depth)
|
|
q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH);
|
|
if (p) {
|
|
swap(q->red_parms, p);
|
|
red_set_parms(q->red_parms,
|
|
ctl_v1->qth_min, ctl_v1->qth_max,
|
|
ctl_v1->Wlog,
|
|
ctl_v1->Plog, ctl_v1->Scell_log,
|
|
NULL,
|
|
ctl_v1->max_P);
|
|
}
|
|
q->flags = ctl_v1->flags;
|
|
q->headdrop = ctl_v1->headdrop;
|
|
}
|
|
if (ctl->limit) {
|
|
q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows);
|
|
q->maxflows = min_t(u32, q->maxflows, q->limit);
|
|
}
|
|
|
|
qlen = sch->q.qlen;
|
|
while (sch->q.qlen > q->limit) {
|
|
dropped += sfq_drop(sch, &to_free);
|
|
if (!tail)
|
|
tail = to_free;
|
|
}
|
|
|
|
rtnl_kfree_skbs(to_free, tail);
|
|
qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped);
|
|
|
|
del_timer(&q->perturb_timer);
|
|
if (q->perturb_period) {
|
|
mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
|
|
get_random_bytes(&q->perturbation, sizeof(q->perturbation));
|
|
}
|
|
sch_tree_unlock(sch);
|
|
kfree(p);
|
|
return 0;
|
|
}
|
|
|
|
static void *sfq_alloc(size_t sz)
|
|
{
|
|
return kvmalloc(sz, GFP_KERNEL);
|
|
}
|
|
|
|
static void sfq_free(void *addr)
|
|
{
|
|
kvfree(addr);
|
|
}
|
|
|
|
static void sfq_destroy(struct Qdisc *sch)
|
|
{
|
|
struct sfq_sched_data *q = qdisc_priv(sch);
|
|
|
|
tcf_block_put(q->block);
|
|
q->perturb_period = 0;
|
|
del_timer_sync(&q->perturb_timer);
|
|
sfq_free(q->ht);
|
|
sfq_free(q->slots);
|
|
kfree(q->red_parms);
|
|
}
|
|
|
|
static int sfq_init(struct Qdisc *sch, struct nlattr *opt,
|
|
struct netlink_ext_ack *extack)
|
|
{
|
|
struct sfq_sched_data *q = qdisc_priv(sch);
|
|
int i;
|
|
int err;
|
|
|
|
q->sch = sch;
|
|
timer_setup(&q->perturb_timer, sfq_perturbation, TIMER_DEFERRABLE);
|
|
|
|
err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
|
|
if (err)
|
|
return err;
|
|
|
|
for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) {
|
|
q->dep[i].next = i + SFQ_MAX_FLOWS;
|
|
q->dep[i].prev = i + SFQ_MAX_FLOWS;
|
|
}
|
|
|
|
q->limit = SFQ_MAX_DEPTH;
|
|
q->maxdepth = SFQ_MAX_DEPTH;
|
|
q->cur_depth = 0;
|
|
q->tail = NULL;
|
|
q->divisor = SFQ_DEFAULT_HASH_DIVISOR;
|
|
q->maxflows = SFQ_DEFAULT_FLOWS;
|
|
q->quantum = psched_mtu(qdisc_dev(sch));
|
|
q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
|
|
q->perturb_period = 0;
|
|
get_random_bytes(&q->perturbation, sizeof(q->perturbation));
|
|
|
|
if (opt) {
|
|
int err = sfq_change(sch, opt);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor);
|
|
q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows);
|
|
if (!q->ht || !q->slots) {
|
|
/* Note: sfq_destroy() will be called by our caller */
|
|
return -ENOMEM;
|
|
}
|
|
|
|
for (i = 0; i < q->divisor; i++)
|
|
q->ht[i] = SFQ_EMPTY_SLOT;
|
|
|
|
for (i = 0; i < q->maxflows; i++) {
|
|
slot_queue_init(&q->slots[i]);
|
|
sfq_link(q, i);
|
|
}
|
|
if (q->limit >= 1)
|
|
sch->flags |= TCQ_F_CAN_BYPASS;
|
|
else
|
|
sch->flags &= ~TCQ_F_CAN_BYPASS;
|
|
return 0;
|
|
}
|
|
|
|
static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
|
|
{
|
|
struct sfq_sched_data *q = qdisc_priv(sch);
|
|
unsigned char *b = skb_tail_pointer(skb);
|
|
struct tc_sfq_qopt_v1 opt;
|
|
struct red_parms *p = q->red_parms;
|
|
|
|
memset(&opt, 0, sizeof(opt));
|
|
opt.v0.quantum = q->quantum;
|
|
opt.v0.perturb_period = q->perturb_period / HZ;
|
|
opt.v0.limit = q->limit;
|
|
opt.v0.divisor = q->divisor;
|
|
opt.v0.flows = q->maxflows;
|
|
opt.depth = q->maxdepth;
|
|
opt.headdrop = q->headdrop;
|
|
|
|
if (p) {
|
|
opt.qth_min = p->qth_min >> p->Wlog;
|
|
opt.qth_max = p->qth_max >> p->Wlog;
|
|
opt.Wlog = p->Wlog;
|
|
opt.Plog = p->Plog;
|
|
opt.Scell_log = p->Scell_log;
|
|
opt.max_P = p->max_P;
|
|
}
|
|
memcpy(&opt.stats, &q->stats, sizeof(opt.stats));
|
|
opt.flags = q->flags;
|
|
|
|
if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
|
|
goto nla_put_failure;
|
|
|
|
return skb->len;
|
|
|
|
nla_put_failure:
|
|
nlmsg_trim(skb, b);
|
|
return -1;
|
|
}
|
|
|
|
static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
static unsigned long sfq_find(struct Qdisc *sch, u32 classid)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent,
|
|
u32 classid)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static void sfq_unbind(struct Qdisc *q, unsigned long cl)
|
|
{
|
|
}
|
|
|
|
static struct tcf_block *sfq_tcf_block(struct Qdisc *sch, unsigned long cl,
|
|
struct netlink_ext_ack *extack)
|
|
{
|
|
struct sfq_sched_data *q = qdisc_priv(sch);
|
|
|
|
if (cl)
|
|
return NULL;
|
|
return q->block;
|
|
}
|
|
|
|
static int sfq_dump_class(struct Qdisc *sch, unsigned long cl,
|
|
struct sk_buff *skb, struct tcmsg *tcm)
|
|
{
|
|
tcm->tcm_handle |= TC_H_MIN(cl);
|
|
return 0;
|
|
}
|
|
|
|
static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
|
|
struct gnet_dump *d)
|
|
{
|
|
struct sfq_sched_data *q = qdisc_priv(sch);
|
|
sfq_index idx = q->ht[cl - 1];
|
|
struct gnet_stats_queue qs = { 0 };
|
|
struct tc_sfq_xstats xstats = { 0 };
|
|
|
|
if (idx != SFQ_EMPTY_SLOT) {
|
|
const struct sfq_slot *slot = &q->slots[idx];
|
|
|
|
xstats.allot = slot->allot << SFQ_ALLOT_SHIFT;
|
|
qs.qlen = slot->qlen;
|
|
qs.backlog = slot->backlog;
|
|
}
|
|
if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
|
|
return -1;
|
|
return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
|
|
}
|
|
|
|
static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
|
|
{
|
|
struct sfq_sched_data *q = qdisc_priv(sch);
|
|
unsigned int i;
|
|
|
|
if (arg->stop)
|
|
return;
|
|
|
|
for (i = 0; i < q->divisor; i++) {
|
|
if (q->ht[i] == SFQ_EMPTY_SLOT) {
|
|
arg->count++;
|
|
continue;
|
|
}
|
|
if (!tc_qdisc_stats_dump(sch, i + 1, arg))
|
|
break;
|
|
}
|
|
}
|
|
|
|
static const struct Qdisc_class_ops sfq_class_ops = {
|
|
.leaf = sfq_leaf,
|
|
.find = sfq_find,
|
|
.tcf_block = sfq_tcf_block,
|
|
.bind_tcf = sfq_bind,
|
|
.unbind_tcf = sfq_unbind,
|
|
.dump = sfq_dump_class,
|
|
.dump_stats = sfq_dump_class_stats,
|
|
.walk = sfq_walk,
|
|
};
|
|
|
|
static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
|
|
.cl_ops = &sfq_class_ops,
|
|
.id = "sfq",
|
|
.priv_size = sizeof(struct sfq_sched_data),
|
|
.enqueue = sfq_enqueue,
|
|
.dequeue = sfq_dequeue,
|
|
.peek = qdisc_peek_dequeued,
|
|
.init = sfq_init,
|
|
.reset = sfq_reset,
|
|
.destroy = sfq_destroy,
|
|
.change = NULL,
|
|
.dump = sfq_dump,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
static int __init sfq_module_init(void)
|
|
{
|
|
return register_qdisc(&sfq_qdisc_ops);
|
|
}
|
|
static void __exit sfq_module_exit(void)
|
|
{
|
|
unregister_qdisc(&sfq_qdisc_ops);
|
|
}
|
|
module_init(sfq_module_init)
|
|
module_exit(sfq_module_exit)
|
|
MODULE_LICENSE("GPL");
|