nixpkgs - Contrib clone of nixpkgs

Age	Commit message (Expand)	Author
2021-01-11	treewide: with stdenv.lib; in meta -> with lib;	Profpatsch
2020-10-27	treewide: remove package names from prefix of descriptions	Ben Siraphob
2019-08-28	treewide: remove redundant rec	volth
2019-08-15	treewide: name -> pname (easy cases) (#66585)	volth
2019-07-07	mjpg-streamer: 2016-03-08 -> unstable-2019-05-24	Gabriel Ebner
2017-11-10	Change many homepage urls from http to https #30636	Pascal Wittmann
2016-06-07	fix 'licenses' -> 'license' in several places	Nikolay Amiantov
2016-03-12	mjpg-streamer: 182 -> 2016-03-08	Nikolay Amiantov
2015-01-20	mjpg-streamer: use postFixup instead of dontPatchElf and NIX_LDFLAGS	Bob van der Linden
2015-01-02	mjpg-streamer: added package	Bob van der Linden

/* * kernel/stop_machine.c * * Copyright (C) 2008, 2005 IBM Corporation. * Copyright (C) 2008, 2005 Rusty Russell rusty@rustcorp.com.au * Copyright (C) 2010 SUSE Linux Products GmbH * Copyright (C) 2010 Tejun Heo <tj@kernel.org> * * This file is released under the GPLv2 and any later version. */ #include <linux/completion.h> #include <linux/cpu.h> #include <linux/init.h> #include <linux/kthread.h> #include <linux/export.h> #include <linux/percpu.h> #include <linux/sched.h> #include <linux/stop_machine.h> #include <linux/interrupt.h> #include <linux/kallsyms.h> #include <linux/smpboot.h> #include <linux/atomic.h> #include <linux/lglock.h> /* * Structure to determine completion condition and record errors. May * be shared by works on different cpus. */ struct cpu_stop_done { atomic_t nr_todo; /* nr left to execute */ bool executed; /* actually executed? */ int ret; /* collected return value */ struct completion completion; /* fired if nr_todo reaches 0 */ }; /* the actual stopper, one per every possible cpu, enabled on online cpus */ struct cpu_stopper { spinlock_t lock; bool enabled; /* is this stopper enabled? */ struct list_head works; /* list of pending works */ }; static DEFINE_PER_CPU(struct cpu_stopper, cpu_stopper); static DEFINE_PER_CPU(struct task_struct *, cpu_stopper_task); static bool stop_machine_initialized = false; /* * Avoids a race between stop_two_cpus and global stop_cpus, where * the stoppers could get queued up in reverse order, leading to * system deadlock. Using an lglock means stop_two_cpus remains * relatively cheap. */ DEFINE_STATIC_LGLOCK(stop_cpus_lock); static void cpu_stop_init_done(struct cpu_stop_done *done, unsigned int nr_todo) { memset(done, 0, sizeof(*done)); atomic_set(&done->nr_todo, nr_todo); init_completion(&done->completion); } /* signal completion unless @done is NULL */ static void cpu_stop_signal_done(struct cpu_stop_done *done, bool executed) { if (done) { if (executed) done->executed = true; if (atomic_dec_and_test(&done->nr_todo)) complete(&done->completion); } } /* queue @work to @stopper. if offline, @work is completed immediately */ static void cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work) { struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); struct task_struct *p = per_cpu(cpu_stopper_task, cpu); unsigned long flags; spin_lock_irqsave(&stopper->lock, flags); if (stopper->enabled) { list_add_tail(&work->list, &stopper->works); wake_up_process(p); } else cpu_stop_signal_done(work->done, false); spin_unlock_irqrestore(&stopper->lock, flags); } /** * stop_one_cpu - stop a cpu * @cpu: cpu to stop * @fn: function to execute * @arg: argument to @fn * * Execute @fn(@arg) on @cpu. @fn is run in a process context with * the highest priority preempting any task on the cpu and * monopolizing it. This function returns after the execution is * complete. * * This function doesn't guarantee @cpu stays online till @fn * completes. If @cpu goes down in the middle, execution may happen * partially or fully on different cpus. @fn should either be ready * for that or the caller should ensure that @cpu stays online until * this function completes. * * CONTEXT: * Might sleep. * * RETURNS: * -ENOENT if @fn(@arg) was not executed because @cpu was offline; * otherwise, the return value of @fn. */ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg) { struct cpu_stop_done done; struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = &done }; cpu_stop_init_done(&done, 1); cpu_stop_queue_work(cpu, &work); wait_for_completion(&done.completion); return done.executed ? done.ret : -ENOENT; } /* This controls the threads on each CPU. */ enum multi_stop_state { /* Dummy starting state for thread. */ MULTI_STOP_NONE, /* Awaiting everyone to be scheduled. */ MULTI_STOP_PREPARE, /* Disable interrupts. */ MULTI_STOP_DISABLE_IRQ, /* Run the function */ MULTI_STOP_RUN, /* Exit */ MULTI_STOP_EXIT, }; struct multi_stop_data { int (*fn)(void *); void *data; /* Like num_online_cpus(), but hotplug cpu uses us, so we need this. */ unsigned int num_threads; const struct cpumask *active_cpus; enum multi_stop_state state; atomic_t thread_ack; }; static void set_state(struct multi_stop_data *msdata, enum multi_stop_state newstate) { /* Reset ack counter. */ atomic_set(&msdata->thread_ack, msdata->num_threads); smp_wmb(); msdata->state = newstate; } /* Last one to ack a state moves to the next state. */ static void ack_state(struct multi_stop_data *msdata) { if (atomic_dec_and_test(&msdata->thread_ack)) set_state(msdata, msdata->state + 1); } /* This is the cpu_stop function which stops the CPU. */ static int multi_cpu_stop(void *data) { struct multi_stop_data *msdata = data; enum multi_stop_state curstate = MULTI_STOP_NONE; int cpu = smp_processor_id(), err = 0; unsigned long flags; bool is_active; /* * When called from stop_machine_from_inactive_cpu(), irq might * already be disabled. Save the state and restore it on exit. */ local_save_flags(flags); if (!msdata->active_cpus) is_active = cpu == cpumask_first(cpu_online_mask); else is_active = cpumask_test_cpu(cpu, msdata->active_cpus); /* Simple state machine */ do { /* Chill out and ensure we re-read multi_stop_state. */ cpu_relax(); if (msdata->state != curstate) { curstate = msdata->state; switch (curstate) { case MULTI_STOP_DISABLE_IRQ: local_irq_disable(); hard_irq_disable(); break; case MULTI_STOP_RUN: if (is_active) err = msdata->fn(msdata->data); break; default: break; } ack_state(msdata); } } while (curstate != MULTI_STOP_EXIT); local_irq_restore(flags); return err; } struct irq_cpu_stop_queue_work_info { int cpu1; int cpu2; struct cpu_stop_work *work1; struct cpu_stop_work *work2; }; /* * This function is always run with irqs and preemption disabled. * This guarantees that both work1 and work2 get queued, before * our local migrate thread gets the chance to preempt us. */ static void irq_cpu_stop_queue_work(void *arg) { struct irq_cpu_stop_queue_work_info *info = arg; cpu_stop_queue_work(info->cpu1, info->work1); cpu_stop_queue_work(info->cpu2, info->work2); } /** * stop_two_cpus - stops two cpus * @cpu1: the cpu to stop * @cpu2: the other cpu to stop * @fn: function to execute * @arg: argument to @fn * * Stops both the current and specified CPU and runs @fn on one of them. * * returns when both are completed. */ int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *arg) { struct cpu_stop_done done; struct cpu_stop_work work1, work2; struct irq_cpu_stop_queue_work_info call_args; struct multi_stop_data msdata; preempt_disable(); msdata = (struct multi_stop_data){ .fn = fn, .data = arg, .num_threads = 2, .active_cpus = cpumask_of(cpu1), }; work1 = work2 = (struct cpu_stop_work){ .fn = multi_cpu_stop, .arg = &msdata, .done = &done };