mirror of
https://github.com/openvswitch/ovs
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a4af24751b
It's (almost) always easier to understand a function with fewer parameters, so this removes the now-redundant sw_flow_key and actions parameters from execute_actions(), since they can be found through OVS_CB(skb)->flow now. This also necessarily moves loop detection into execute_actions(). Otherwise, the flow's actions could have changed between the time that the loop was detected and the time that it was suppressed, which would mean that the wrong (version of the) flow would get suppressed. Signed-off-by: Ben Pfaff <blp@nicira.com> Acked-by: Jesse Gross <jesse@nicira.com>
73 lines
1.8 KiB
C
73 lines
1.8 KiB
C
/*
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* Distributed under the terms of the GNU GPL version 2.
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* Copyright (c) 2010, 2011 Nicira Networks.
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*
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* Significant portions of this file may be copied from parts of the Linux
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* kernel, by Linus Torvalds and others.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/hardirq.h>
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#include <linux/kernel.h>
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#include <linux/percpu.h>
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#include <linux/sched.h>
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#include "loop_counter.h"
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int loop_suppress(struct datapath *dp, struct sw_flow_actions *actions)
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{
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if (net_ratelimit())
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pr_warn("%s: flow looped %d times, dropping\n",
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dp_name(dp), MAX_LOOPS);
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actions->actions_len = 0;
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return -ELOOP;
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}
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#ifndef CONFIG_PREEMPT_RT
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/* We use a separate counter for each CPU for both interrupt and non-interrupt
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* context in order to keep the limit deterministic for a given packet.
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*/
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struct percpu_loop_counters {
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struct loop_counter counters[2];
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};
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static DEFINE_PER_CPU(struct percpu_loop_counters, loop_counters);
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struct loop_counter *loop_get_counter(void)
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{
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return &get_cpu_var(loop_counters).counters[!!in_interrupt()];
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}
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void loop_put_counter(void)
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{
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put_cpu_var(loop_counters);
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}
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#else /* !CONFIG_PREEMPT_RT */
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struct loop_counter *loop_get_counter(void)
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{
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WARN_ON(in_interrupt());
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/* Only two bits of the extra_flags field in struct task_struct are
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* used and it's an unsigned int. We hijack the most significant bits
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* to be our counter structure. On RT kernels softirqs always run in
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* process context so we are guaranteed to have a valid task_struct.
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*/
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#ifdef __LITTLE_ENDIAN
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return (void *)(¤t->extra_flags + 1) -
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sizeof(struct loop_counter);
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#elif __BIG_ENDIAN
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return (struct loop_counter *)¤t->extra_flags;
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#else
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#error "Please fix <asm/byteorder.h>."
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#endif
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}
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void loop_put_counter(void) { }
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#endif /* CONFIG_PREEMPT_RT */
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