85c1b3c1cb
Previusly the slow path was folded in and partially jumped over in the common case.
856 lines
20 KiB
C
856 lines
20 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 2007 Stephan Uphoff <ups@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Machine independent bits of reader/writer lock implementation.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_ddb.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/kdb.h>
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#include <sys/ktr.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/rmlock.h>
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#include <sys/sched.h>
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#include <sys/smp.h>
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#include <sys/turnstile.h>
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#include <sys/lock_profile.h>
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#include <machine/cpu.h>
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#ifdef DDB
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#include <ddb/ddb.h>
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#endif
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/*
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* A cookie to mark destroyed rmlocks. This is stored in the head of
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* rm_activeReaders.
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*/
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#define RM_DESTROYED ((void *)0xdead)
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#define rm_destroyed(rm) \
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(LIST_FIRST(&(rm)->rm_activeReaders) == RM_DESTROYED)
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#define RMPF_ONQUEUE 1
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#define RMPF_SIGNAL 2
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#ifndef INVARIANTS
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#define _rm_assert(c, what, file, line)
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#endif
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static void assert_rm(const struct lock_object *lock, int what);
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#ifdef DDB
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static void db_show_rm(const struct lock_object *lock);
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#endif
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static void lock_rm(struct lock_object *lock, uintptr_t how);
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#ifdef KDTRACE_HOOKS
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static int owner_rm(const struct lock_object *lock, struct thread **owner);
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#endif
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static uintptr_t unlock_rm(struct lock_object *lock);
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struct lock_class lock_class_rm = {
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.lc_name = "rm",
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.lc_flags = LC_SLEEPLOCK | LC_RECURSABLE,
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.lc_assert = assert_rm,
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#ifdef DDB
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.lc_ddb_show = db_show_rm,
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#endif
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.lc_lock = lock_rm,
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.lc_unlock = unlock_rm,
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#ifdef KDTRACE_HOOKS
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.lc_owner = owner_rm,
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#endif
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};
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struct lock_class lock_class_rm_sleepable = {
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.lc_name = "sleepable rm",
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.lc_flags = LC_SLEEPLOCK | LC_SLEEPABLE | LC_RECURSABLE,
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.lc_assert = assert_rm,
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#ifdef DDB
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.lc_ddb_show = db_show_rm,
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#endif
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.lc_lock = lock_rm,
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.lc_unlock = unlock_rm,
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#ifdef KDTRACE_HOOKS
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.lc_owner = owner_rm,
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#endif
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};
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static void
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assert_rm(const struct lock_object *lock, int what)
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{
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rm_assert((const struct rmlock *)lock, what);
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}
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static void
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lock_rm(struct lock_object *lock, uintptr_t how)
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{
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struct rmlock *rm;
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struct rm_priotracker *tracker;
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rm = (struct rmlock *)lock;
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if (how == 0)
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rm_wlock(rm);
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else {
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tracker = (struct rm_priotracker *)how;
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rm_rlock(rm, tracker);
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}
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}
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static uintptr_t
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unlock_rm(struct lock_object *lock)
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{
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struct thread *td;
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struct pcpu *pc;
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struct rmlock *rm;
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struct rm_queue *queue;
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struct rm_priotracker *tracker;
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uintptr_t how;
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rm = (struct rmlock *)lock;
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tracker = NULL;
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how = 0;
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rm_assert(rm, RA_LOCKED | RA_NOTRECURSED);
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if (rm_wowned(rm))
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rm_wunlock(rm);
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else {
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/*
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* Find the right rm_priotracker structure for curthread.
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* The guarantee about its uniqueness is given by the fact
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* we already asserted the lock wasn't recursively acquired.
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*/
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critical_enter();
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td = curthread;
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pc = get_pcpu();
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for (queue = pc->pc_rm_queue.rmq_next;
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queue != &pc->pc_rm_queue; queue = queue->rmq_next) {
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tracker = (struct rm_priotracker *)queue;
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if ((tracker->rmp_rmlock == rm) &&
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(tracker->rmp_thread == td)) {
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how = (uintptr_t)tracker;
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break;
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}
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}
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KASSERT(tracker != NULL,
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("rm_priotracker is non-NULL when lock held in read mode"));
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critical_exit();
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rm_runlock(rm, tracker);
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}
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return (how);
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}
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#ifdef KDTRACE_HOOKS
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static int
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owner_rm(const struct lock_object *lock, struct thread **owner)
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{
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const struct rmlock *rm;
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struct lock_class *lc;
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rm = (const struct rmlock *)lock;
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lc = LOCK_CLASS(&rm->rm_wlock_object);
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return (lc->lc_owner(&rm->rm_wlock_object, owner));
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}
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#endif
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static struct mtx rm_spinlock;
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MTX_SYSINIT(rm_spinlock, &rm_spinlock, "rm_spinlock", MTX_SPIN);
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/*
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* Add or remove tracker from per-cpu list.
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*
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* The per-cpu list can be traversed at any time in forward direction from an
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* interrupt on the *local* cpu.
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*/
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static void inline
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rm_tracker_add(struct pcpu *pc, struct rm_priotracker *tracker)
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{
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struct rm_queue *next;
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/* Initialize all tracker pointers */
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tracker->rmp_cpuQueue.rmq_prev = &pc->pc_rm_queue;
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next = pc->pc_rm_queue.rmq_next;
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tracker->rmp_cpuQueue.rmq_next = next;
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/* rmq_prev is not used during froward traversal. */
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next->rmq_prev = &tracker->rmp_cpuQueue;
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/* Update pointer to first element. */
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pc->pc_rm_queue.rmq_next = &tracker->rmp_cpuQueue;
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}
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/*
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* Return a count of the number of trackers the thread 'td' already
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* has on this CPU for the lock 'rm'.
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*/
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static int
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rm_trackers_present(const struct pcpu *pc, const struct rmlock *rm,
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const struct thread *td)
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{
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struct rm_queue *queue;
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struct rm_priotracker *tracker;
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int count;
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count = 0;
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for (queue = pc->pc_rm_queue.rmq_next; queue != &pc->pc_rm_queue;
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queue = queue->rmq_next) {
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tracker = (struct rm_priotracker *)queue;
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if ((tracker->rmp_rmlock == rm) && (tracker->rmp_thread == td))
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count++;
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}
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return (count);
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}
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static void inline
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rm_tracker_remove(struct pcpu *pc, struct rm_priotracker *tracker)
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{
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struct rm_queue *next, *prev;
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next = tracker->rmp_cpuQueue.rmq_next;
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prev = tracker->rmp_cpuQueue.rmq_prev;
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/* Not used during forward traversal. */
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next->rmq_prev = prev;
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/* Remove from list. */
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prev->rmq_next = next;
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}
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static void
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rm_cleanIPI(void *arg)
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{
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struct pcpu *pc;
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struct rmlock *rm = arg;
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struct rm_priotracker *tracker;
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struct rm_queue *queue;
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pc = get_pcpu();
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for (queue = pc->pc_rm_queue.rmq_next; queue != &pc->pc_rm_queue;
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queue = queue->rmq_next) {
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tracker = (struct rm_priotracker *)queue;
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if (tracker->rmp_rmlock == rm && tracker->rmp_flags == 0) {
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tracker->rmp_flags = RMPF_ONQUEUE;
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mtx_lock_spin(&rm_spinlock);
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LIST_INSERT_HEAD(&rm->rm_activeReaders, tracker,
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rmp_qentry);
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mtx_unlock_spin(&rm_spinlock);
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}
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}
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}
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void
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rm_init_flags(struct rmlock *rm, const char *name, int opts)
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{
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struct lock_class *lc;
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int liflags, xflags;
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liflags = 0;
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if (!(opts & RM_NOWITNESS))
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liflags |= LO_WITNESS;
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if (opts & RM_RECURSE)
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liflags |= LO_RECURSABLE;
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if (opts & RM_NEW)
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liflags |= LO_NEW;
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rm->rm_writecpus = all_cpus;
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LIST_INIT(&rm->rm_activeReaders);
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if (opts & RM_SLEEPABLE) {
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liflags |= LO_SLEEPABLE;
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lc = &lock_class_rm_sleepable;
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xflags = (opts & RM_NEW ? SX_NEW : 0);
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sx_init_flags(&rm->rm_lock_sx, "rmlock_sx",
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xflags | SX_NOWITNESS);
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} else {
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lc = &lock_class_rm;
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xflags = (opts & RM_NEW ? MTX_NEW : 0);
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mtx_init(&rm->rm_lock_mtx, name, "rmlock_mtx",
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xflags | MTX_NOWITNESS);
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}
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lock_init(&rm->lock_object, lc, name, NULL, liflags);
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}
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void
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rm_init(struct rmlock *rm, const char *name)
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{
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rm_init_flags(rm, name, 0);
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}
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void
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rm_destroy(struct rmlock *rm)
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{
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rm_assert(rm, RA_UNLOCKED);
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LIST_FIRST(&rm->rm_activeReaders) = RM_DESTROYED;
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if (rm->lock_object.lo_flags & LO_SLEEPABLE)
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sx_destroy(&rm->rm_lock_sx);
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else
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mtx_destroy(&rm->rm_lock_mtx);
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lock_destroy(&rm->lock_object);
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}
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int
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rm_wowned(const struct rmlock *rm)
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{
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if (rm->lock_object.lo_flags & LO_SLEEPABLE)
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return (sx_xlocked(&rm->rm_lock_sx));
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else
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return (mtx_owned(&rm->rm_lock_mtx));
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}
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void
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rm_sysinit(void *arg)
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{
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struct rm_args *args;
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args = arg;
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rm_init_flags(args->ra_rm, args->ra_desc, args->ra_flags);
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}
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static __noinline int
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_rm_rlock_hard(struct rmlock *rm, struct rm_priotracker *tracker, int trylock)
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{
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struct pcpu *pc;
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critical_enter();
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pc = get_pcpu();
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/* Check if we just need to do a proper critical_exit. */
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if (!CPU_ISSET(pc->pc_cpuid, &rm->rm_writecpus)) {
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critical_exit();
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return (1);
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}
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/* Remove our tracker from the per-cpu list. */
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rm_tracker_remove(pc, tracker);
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/* Check to see if the IPI granted us the lock after all. */
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if (tracker->rmp_flags) {
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/* Just add back tracker - we hold the lock. */
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rm_tracker_add(pc, tracker);
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critical_exit();
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return (1);
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}
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/*
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* We allow readers to acquire a lock even if a writer is blocked if
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* the lock is recursive and the reader already holds the lock.
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*/
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if ((rm->lock_object.lo_flags & LO_RECURSABLE) != 0) {
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/*
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* Just grant the lock if this thread already has a tracker
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* for this lock on the per-cpu queue.
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*/
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if (rm_trackers_present(pc, rm, curthread) != 0) {
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mtx_lock_spin(&rm_spinlock);
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LIST_INSERT_HEAD(&rm->rm_activeReaders, tracker,
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rmp_qentry);
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tracker->rmp_flags = RMPF_ONQUEUE;
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mtx_unlock_spin(&rm_spinlock);
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rm_tracker_add(pc, tracker);
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critical_exit();
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return (1);
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}
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}
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sched_unpin();
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critical_exit();
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if (trylock) {
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if (rm->lock_object.lo_flags & LO_SLEEPABLE) {
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if (!sx_try_xlock(&rm->rm_lock_sx))
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return (0);
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} else {
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if (!mtx_trylock(&rm->rm_lock_mtx))
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return (0);
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}
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} else {
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if (rm->lock_object.lo_flags & LO_SLEEPABLE) {
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THREAD_SLEEPING_OK();
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sx_xlock(&rm->rm_lock_sx);
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THREAD_NO_SLEEPING();
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} else
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mtx_lock(&rm->rm_lock_mtx);
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}
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critical_enter();
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pc = get_pcpu();
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CPU_CLR(pc->pc_cpuid, &rm->rm_writecpus);
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rm_tracker_add(pc, tracker);
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sched_pin();
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critical_exit();
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if (rm->lock_object.lo_flags & LO_SLEEPABLE)
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sx_xunlock(&rm->rm_lock_sx);
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else
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mtx_unlock(&rm->rm_lock_mtx);
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return (1);
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}
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int
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_rm_rlock(struct rmlock *rm, struct rm_priotracker *tracker, int trylock)
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{
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struct thread *td = curthread;
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struct pcpu *pc;
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if (SCHEDULER_STOPPED())
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return (1);
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tracker->rmp_flags = 0;
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tracker->rmp_thread = td;
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tracker->rmp_rmlock = rm;
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if (rm->lock_object.lo_flags & LO_SLEEPABLE)
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THREAD_NO_SLEEPING();
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td->td_critnest++; /* critical_enter(); */
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__compiler_membar();
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pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */
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rm_tracker_add(pc, tracker);
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sched_pin();
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__compiler_membar();
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td->td_critnest--;
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/*
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* Fast path to combine two common conditions into a single
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* conditional jump.
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*/
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if (__predict_true(0 == (td->td_owepreempt |
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CPU_ISSET(pc->pc_cpuid, &rm->rm_writecpus))))
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return (1);
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/* We do not have a read token and need to acquire one. */
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return _rm_rlock_hard(rm, tracker, trylock);
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}
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static __noinline void
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_rm_unlock_hard(struct thread *td,struct rm_priotracker *tracker)
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{
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if (td->td_owepreempt) {
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td->td_critnest++;
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critical_exit();
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}
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if (!tracker->rmp_flags)
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return;
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mtx_lock_spin(&rm_spinlock);
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LIST_REMOVE(tracker, rmp_qentry);
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if (tracker->rmp_flags & RMPF_SIGNAL) {
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struct rmlock *rm;
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struct turnstile *ts;
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rm = tracker->rmp_rmlock;
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turnstile_chain_lock(&rm->lock_object);
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mtx_unlock_spin(&rm_spinlock);
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ts = turnstile_lookup(&rm->lock_object);
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turnstile_signal(ts, TS_EXCLUSIVE_QUEUE);
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turnstile_unpend(ts, TS_EXCLUSIVE_LOCK);
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turnstile_chain_unlock(&rm->lock_object);
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} else
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mtx_unlock_spin(&rm_spinlock);
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}
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void
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_rm_runlock(struct rmlock *rm, struct rm_priotracker *tracker)
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{
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struct pcpu *pc;
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struct thread *td = tracker->rmp_thread;
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if (SCHEDULER_STOPPED())
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return;
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td->td_critnest++; /* critical_enter(); */
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pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */
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rm_tracker_remove(pc, tracker);
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td->td_critnest--;
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sched_unpin();
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if (rm->lock_object.lo_flags & LO_SLEEPABLE)
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THREAD_SLEEPING_OK();
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if (__predict_true(0 == (td->td_owepreempt | tracker->rmp_flags)))
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return;
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_rm_unlock_hard(td, tracker);
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}
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void
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_rm_wlock(struct rmlock *rm)
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|
{
|
|
struct rm_priotracker *prio;
|
|
struct turnstile *ts;
|
|
cpuset_t readcpus;
|
|
|
|
if (SCHEDULER_STOPPED())
|
|
return;
|
|
|
|
if (rm->lock_object.lo_flags & LO_SLEEPABLE)
|
|
sx_xlock(&rm->rm_lock_sx);
|
|
else
|
|
mtx_lock(&rm->rm_lock_mtx);
|
|
|
|
if (CPU_CMP(&rm->rm_writecpus, &all_cpus)) {
|
|
/* Get all read tokens back */
|
|
readcpus = all_cpus;
|
|
CPU_NAND(&readcpus, &rm->rm_writecpus);
|
|
rm->rm_writecpus = all_cpus;
|
|
|
|
/*
|
|
* Assumes rm->rm_writecpus update is visible on other CPUs
|
|
* before rm_cleanIPI is called.
|
|
*/
|
|
#ifdef SMP
|
|
smp_rendezvous_cpus(readcpus,
|
|
smp_no_rendezvous_barrier,
|
|
rm_cleanIPI,
|
|
smp_no_rendezvous_barrier,
|
|
rm);
|
|
|
|
#else
|
|
rm_cleanIPI(rm);
|
|
#endif
|
|
|
|
mtx_lock_spin(&rm_spinlock);
|
|
while ((prio = LIST_FIRST(&rm->rm_activeReaders)) != NULL) {
|
|
ts = turnstile_trywait(&rm->lock_object);
|
|
prio->rmp_flags = RMPF_ONQUEUE | RMPF_SIGNAL;
|
|
mtx_unlock_spin(&rm_spinlock);
|
|
turnstile_wait(ts, prio->rmp_thread,
|
|
TS_EXCLUSIVE_QUEUE);
|
|
mtx_lock_spin(&rm_spinlock);
|
|
}
|
|
mtx_unlock_spin(&rm_spinlock);
|
|
}
|
|
}
|
|
|
|
void
|
|
_rm_wunlock(struct rmlock *rm)
|
|
{
|
|
|
|
if (rm->lock_object.lo_flags & LO_SLEEPABLE)
|
|
sx_xunlock(&rm->rm_lock_sx);
|
|
else
|
|
mtx_unlock(&rm->rm_lock_mtx);
|
|
}
|
|
|
|
#if LOCK_DEBUG > 0
|
|
|
|
void
|
|
_rm_wlock_debug(struct rmlock *rm, const char *file, int line)
|
|
{
|
|
|
|
if (SCHEDULER_STOPPED())
|
|
return;
|
|
|
|
KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread),
|
|
("rm_wlock() by idle thread %p on rmlock %s @ %s:%d",
|
|
curthread, rm->lock_object.lo_name, file, line));
|
|
KASSERT(!rm_destroyed(rm),
|
|
("rm_wlock() of destroyed rmlock @ %s:%d", file, line));
|
|
_rm_assert(rm, RA_UNLOCKED, file, line);
|
|
|
|
WITNESS_CHECKORDER(&rm->lock_object, LOP_NEWORDER | LOP_EXCLUSIVE,
|
|
file, line, NULL);
|
|
|
|
_rm_wlock(rm);
|
|
|
|
LOCK_LOG_LOCK("RMWLOCK", &rm->lock_object, 0, 0, file, line);
|
|
WITNESS_LOCK(&rm->lock_object, LOP_EXCLUSIVE, file, line);
|
|
TD_LOCKS_INC(curthread);
|
|
}
|
|
|
|
void
|
|
_rm_wunlock_debug(struct rmlock *rm, const char *file, int line)
|
|
{
|
|
|
|
if (SCHEDULER_STOPPED())
|
|
return;
|
|
|
|
KASSERT(!rm_destroyed(rm),
|
|
("rm_wunlock() of destroyed rmlock @ %s:%d", file, line));
|
|
_rm_assert(rm, RA_WLOCKED, file, line);
|
|
WITNESS_UNLOCK(&rm->lock_object, LOP_EXCLUSIVE, file, line);
|
|
LOCK_LOG_LOCK("RMWUNLOCK", &rm->lock_object, 0, 0, file, line);
|
|
_rm_wunlock(rm);
|
|
TD_LOCKS_DEC(curthread);
|
|
}
|
|
|
|
int
|
|
_rm_rlock_debug(struct rmlock *rm, struct rm_priotracker *tracker,
|
|
int trylock, const char *file, int line)
|
|
{
|
|
|
|
if (SCHEDULER_STOPPED())
|
|
return (1);
|
|
|
|
#ifdef INVARIANTS
|
|
if (!(rm->lock_object.lo_flags & LO_RECURSABLE) && !trylock) {
|
|
critical_enter();
|
|
KASSERT(rm_trackers_present(get_pcpu(), rm,
|
|
curthread) == 0,
|
|
("rm_rlock: recursed on non-recursive rmlock %s @ %s:%d\n",
|
|
rm->lock_object.lo_name, file, line));
|
|
critical_exit();
|
|
}
|
|
#endif
|
|
KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread),
|
|
("rm_rlock() by idle thread %p on rmlock %s @ %s:%d",
|
|
curthread, rm->lock_object.lo_name, file, line));
|
|
KASSERT(!rm_destroyed(rm),
|
|
("rm_rlock() of destroyed rmlock @ %s:%d", file, line));
|
|
if (!trylock) {
|
|
KASSERT(!rm_wowned(rm),
|
|
("rm_rlock: wlock already held for %s @ %s:%d",
|
|
rm->lock_object.lo_name, file, line));
|
|
WITNESS_CHECKORDER(&rm->lock_object, LOP_NEWORDER, file, line,
|
|
NULL);
|
|
}
|
|
|
|
if (_rm_rlock(rm, tracker, trylock)) {
|
|
if (trylock)
|
|
LOCK_LOG_TRY("RMRLOCK", &rm->lock_object, 0, 1, file,
|
|
line);
|
|
else
|
|
LOCK_LOG_LOCK("RMRLOCK", &rm->lock_object, 0, 0, file,
|
|
line);
|
|
WITNESS_LOCK(&rm->lock_object, 0, file, line);
|
|
TD_LOCKS_INC(curthread);
|
|
return (1);
|
|
} else if (trylock)
|
|
LOCK_LOG_TRY("RMRLOCK", &rm->lock_object, 0, 0, file, line);
|
|
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
_rm_runlock_debug(struct rmlock *rm, struct rm_priotracker *tracker,
|
|
const char *file, int line)
|
|
{
|
|
|
|
if (SCHEDULER_STOPPED())
|
|
return;
|
|
|
|
KASSERT(!rm_destroyed(rm),
|
|
("rm_runlock() of destroyed rmlock @ %s:%d", file, line));
|
|
_rm_assert(rm, RA_RLOCKED, file, line);
|
|
WITNESS_UNLOCK(&rm->lock_object, 0, file, line);
|
|
LOCK_LOG_LOCK("RMRUNLOCK", &rm->lock_object, 0, 0, file, line);
|
|
_rm_runlock(rm, tracker);
|
|
TD_LOCKS_DEC(curthread);
|
|
}
|
|
|
|
#else
|
|
|
|
/*
|
|
* Just strip out file and line arguments if no lock debugging is enabled in
|
|
* the kernel - we are called from a kernel module.
|
|
*/
|
|
void
|
|
_rm_wlock_debug(struct rmlock *rm, const char *file, int line)
|
|
{
|
|
|
|
_rm_wlock(rm);
|
|
}
|
|
|
|
void
|
|
_rm_wunlock_debug(struct rmlock *rm, const char *file, int line)
|
|
{
|
|
|
|
_rm_wunlock(rm);
|
|
}
|
|
|
|
int
|
|
_rm_rlock_debug(struct rmlock *rm, struct rm_priotracker *tracker,
|
|
int trylock, const char *file, int line)
|
|
{
|
|
|
|
return _rm_rlock(rm, tracker, trylock);
|
|
}
|
|
|
|
void
|
|
_rm_runlock_debug(struct rmlock *rm, struct rm_priotracker *tracker,
|
|
const char *file, int line)
|
|
{
|
|
|
|
_rm_runlock(rm, tracker);
|
|
}
|
|
|
|
#endif
|
|
|
|
#ifdef INVARIANT_SUPPORT
|
|
#ifndef INVARIANTS
|
|
#undef _rm_assert
|
|
#endif
|
|
|
|
/*
|
|
* Note that this does not need to use witness_assert() for read lock
|
|
* assertions since an exact count of read locks held by this thread
|
|
* is computable.
|
|
*/
|
|
void
|
|
_rm_assert(const struct rmlock *rm, int what, const char *file, int line)
|
|
{
|
|
int count;
|
|
|
|
if (panicstr != NULL)
|
|
return;
|
|
switch (what) {
|
|
case RA_LOCKED:
|
|
case RA_LOCKED | RA_RECURSED:
|
|
case RA_LOCKED | RA_NOTRECURSED:
|
|
case RA_RLOCKED:
|
|
case RA_RLOCKED | RA_RECURSED:
|
|
case RA_RLOCKED | RA_NOTRECURSED:
|
|
/*
|
|
* Handle the write-locked case. Unlike other
|
|
* primitives, writers can never recurse.
|
|
*/
|
|
if (rm_wowned(rm)) {
|
|
if (what & RA_RLOCKED)
|
|
panic("Lock %s exclusively locked @ %s:%d\n",
|
|
rm->lock_object.lo_name, file, line);
|
|
if (what & RA_RECURSED)
|
|
panic("Lock %s not recursed @ %s:%d\n",
|
|
rm->lock_object.lo_name, file, line);
|
|
break;
|
|
}
|
|
|
|
critical_enter();
|
|
count = rm_trackers_present(get_pcpu(), rm, curthread);
|
|
critical_exit();
|
|
|
|
if (count == 0)
|
|
panic("Lock %s not %slocked @ %s:%d\n",
|
|
rm->lock_object.lo_name, (what & RA_RLOCKED) ?
|
|
"read " : "", file, line);
|
|
if (count > 1) {
|
|
if (what & RA_NOTRECURSED)
|
|
panic("Lock %s recursed @ %s:%d\n",
|
|
rm->lock_object.lo_name, file, line);
|
|
} else if (what & RA_RECURSED)
|
|
panic("Lock %s not recursed @ %s:%d\n",
|
|
rm->lock_object.lo_name, file, line);
|
|
break;
|
|
case RA_WLOCKED:
|
|
if (!rm_wowned(rm))
|
|
panic("Lock %s not exclusively locked @ %s:%d\n",
|
|
rm->lock_object.lo_name, file, line);
|
|
break;
|
|
case RA_UNLOCKED:
|
|
if (rm_wowned(rm))
|
|
panic("Lock %s exclusively locked @ %s:%d\n",
|
|
rm->lock_object.lo_name, file, line);
|
|
|
|
critical_enter();
|
|
count = rm_trackers_present(get_pcpu(), rm, curthread);
|
|
critical_exit();
|
|
|
|
if (count != 0)
|
|
panic("Lock %s read locked @ %s:%d\n",
|
|
rm->lock_object.lo_name, file, line);
|
|
break;
|
|
default:
|
|
panic("Unknown rm lock assertion: %d @ %s:%d", what, file,
|
|
line);
|
|
}
|
|
}
|
|
#endif /* INVARIANT_SUPPORT */
|
|
|
|
#ifdef DDB
|
|
static void
|
|
print_tracker(struct rm_priotracker *tr)
|
|
{
|
|
struct thread *td;
|
|
|
|
td = tr->rmp_thread;
|
|
db_printf(" thread %p (tid %d, pid %d, \"%s\") {", td, td->td_tid,
|
|
td->td_proc->p_pid, td->td_name);
|
|
if (tr->rmp_flags & RMPF_ONQUEUE) {
|
|
db_printf("ONQUEUE");
|
|
if (tr->rmp_flags & RMPF_SIGNAL)
|
|
db_printf(",SIGNAL");
|
|
} else
|
|
db_printf("0");
|
|
db_printf("}\n");
|
|
}
|
|
|
|
static void
|
|
db_show_rm(const struct lock_object *lock)
|
|
{
|
|
struct rm_priotracker *tr;
|
|
struct rm_queue *queue;
|
|
const struct rmlock *rm;
|
|
struct lock_class *lc;
|
|
struct pcpu *pc;
|
|
|
|
rm = (const struct rmlock *)lock;
|
|
db_printf(" writecpus: ");
|
|
ddb_display_cpuset(__DEQUALIFY(const cpuset_t *, &rm->rm_writecpus));
|
|
db_printf("\n");
|
|
db_printf(" per-CPU readers:\n");
|
|
STAILQ_FOREACH(pc, &cpuhead, pc_allcpu)
|
|
for (queue = pc->pc_rm_queue.rmq_next;
|
|
queue != &pc->pc_rm_queue; queue = queue->rmq_next) {
|
|
tr = (struct rm_priotracker *)queue;
|
|
if (tr->rmp_rmlock == rm)
|
|
print_tracker(tr);
|
|
}
|
|
db_printf(" active readers:\n");
|
|
LIST_FOREACH(tr, &rm->rm_activeReaders, rmp_qentry)
|
|
print_tracker(tr);
|
|
lc = LOCK_CLASS(&rm->rm_wlock_object);
|
|
db_printf("Backing write-lock (%s):\n", lc->lc_name);
|
|
lc->lc_ddb_show(&rm->rm_wlock_object);
|
|
}
|
|
#endif
|