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ac6e5fb202
There are a number of places where cv_?_sig is used simply for accounting purposes but the surrounding code has no ability to cope with actually receiving a signal. On FreeBSD it is possible to send signals to individual kernel threads so this could enable undesirable behavior. This patch adds routines on Linux that will do the same idle accounting as _sig without making the task interruptible. On FreeBSD cv_*_idle are all aliases for cv_* Reviewed-by: Alexander Motin <mav@FreeBSD.org> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Matt Macy <mmacy@FreeBSD.org> Closes #10843
121 lines
4.8 KiB
C
121 lines
4.8 KiB
C
/*
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* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
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* Copyright (C) 2007 The Regents of the University of California.
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* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
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* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
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* UCRL-CODE-235197
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*
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* This file is part of the SPL, Solaris Porting Layer.
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* For details, see <http://zfsonlinux.org/>.
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*
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* The SPL is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* The SPL is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with the SPL. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _SPL_CONDVAR_H
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#define _SPL_CONDVAR_H
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#include <linux/module.h>
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#include <sys/kmem.h>
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#include <sys/mutex.h>
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#include <sys/callo.h>
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#include <sys/wait.h>
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#include <sys/time.h>
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/*
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* cv_timedwait() is similar to cv_wait() except that it additionally expects
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* a timeout value specified in ticks. When woken by cv_signal() or
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* cv_broadcast() it returns 1, otherwise when the timeout is reached -1 is
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* returned.
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*
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* cv_timedwait_sig() behaves the same as cv_timedwait() but blocks
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* interruptibly and can be woken by a signal (EINTR, ERESTART). When
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* this occurs 0 is returned.
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*
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* cv_timedwait_io() and cv_timedwait_sig_io() are variants of cv_timedwait()
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* and cv_timedwait_sig() which should be used when waiting for outstanding
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* IO to complete. They are responsible for updating the iowait accounting
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* when this is supported by the platform.
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*
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* cv_timedwait_hires() and cv_timedwait_sig_hires() are high resolution
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* versions of cv_timedwait() and cv_timedwait_sig(). They expect the timeout
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* to be specified as a hrtime_t allowing for timeouts of less than a tick.
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*
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* N.B. The return values differ slightly from the illumos implementation
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* which returns the time remaining, instead of 1, when woken. They both
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* return -1 on timeout. Consumers which need to know the time remaining
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* are responsible for tracking it themselves.
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*/
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/*
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* The kcondvar_t struct is protected by mutex taken externally before
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* calling any of the wait/signal funs, and passed into the wait funs.
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*/
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#define CV_MAGIC 0x346545f4
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#define CV_DESTROY 0x346545f5
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typedef struct {
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int cv_magic;
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spl_wait_queue_head_t cv_event;
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spl_wait_queue_head_t cv_destroy;
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atomic_t cv_refs;
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atomic_t cv_waiters;
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kmutex_t *cv_mutex;
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} kcondvar_t;
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typedef enum { CV_DEFAULT = 0, CV_DRIVER } kcv_type_t;
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extern void __cv_init(kcondvar_t *, char *, kcv_type_t, void *);
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extern void __cv_destroy(kcondvar_t *);
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extern void __cv_wait(kcondvar_t *, kmutex_t *);
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extern void __cv_wait_io(kcondvar_t *, kmutex_t *);
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extern void __cv_wait_idle(kcondvar_t *, kmutex_t *);
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extern int __cv_wait_io_sig(kcondvar_t *, kmutex_t *);
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extern int __cv_wait_sig(kcondvar_t *, kmutex_t *);
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extern int __cv_timedwait(kcondvar_t *, kmutex_t *, clock_t);
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extern int __cv_timedwait_io(kcondvar_t *, kmutex_t *, clock_t);
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extern int __cv_timedwait_sig(kcondvar_t *, kmutex_t *, clock_t);
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extern int __cv_timedwait_idle(kcondvar_t *, kmutex_t *, clock_t);
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extern int cv_timedwait_hires(kcondvar_t *, kmutex_t *, hrtime_t,
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hrtime_t res, int flag);
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extern int cv_timedwait_sig_hires(kcondvar_t *, kmutex_t *, hrtime_t,
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hrtime_t res, int flag);
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extern int cv_timedwait_idle_hires(kcondvar_t *, kmutex_t *, hrtime_t,
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hrtime_t res, int flag);
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extern void __cv_signal(kcondvar_t *);
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extern void __cv_broadcast(kcondvar_t *c);
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#define cv_init(cvp, name, type, arg) __cv_init(cvp, name, type, arg)
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#define cv_destroy(cvp) __cv_destroy(cvp)
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#define cv_wait(cvp, mp) __cv_wait(cvp, mp)
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#define cv_wait_io(cvp, mp) __cv_wait_io(cvp, mp)
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#define cv_wait_idle(cvp, mp) __cv_wait_idle(cvp, mp)
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#define cv_wait_io_sig(cvp, mp) __cv_wait_io_sig(cvp, mp)
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#define cv_wait_sig(cvp, mp) __cv_wait_sig(cvp, mp)
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#define cv_signal(cvp) __cv_signal(cvp)
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#define cv_broadcast(cvp) __cv_broadcast(cvp)
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/*
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* NB: There is no way to reliably distinguish between having been signalled
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* and having timed out on Linux. If the client code needs to reliably
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* distinguish between the two it should use the hires variant.
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*/
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#define cv_timedwait(cvp, mp, t) __cv_timedwait(cvp, mp, t)
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#define cv_timedwait_io(cvp, mp, t) __cv_timedwait_io(cvp, mp, t)
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#define cv_timedwait_sig(cvp, mp, t) __cv_timedwait_sig(cvp, mp, t)
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#define cv_timedwait_idle(cvp, mp, t) __cv_timedwait_idle(cvp, mp, t)
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#endif /* _SPL_CONDVAR_H */
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