IABSD.fr/src/sys/kern/subr_xxx.c

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• Author : visa
  Date : 2019-05-17 03:53:08
  Hash : 9e473608
  Message : Add SMR_ASSERT_NONCRITICAL() in assertwaitok(). This eases debugging because now the error is detected before context switch. The sleep code path eventually calls assertwaitok() in mi_switch(), so the assertwaitok() in the SMR barrier function is somewhat redundant and can be removed. OK mpi@

• sys/kern/subr_xxx.c

• /*	$OpenBSD: subr_xxx.c,v 1.17 2019/05/17 03:53:08 visa Exp $	*/
  /*	$NetBSD: subr_xxx.c,v 1.10 1996/02/04 02:16:51 christos Exp $	*/
  
  /*
   * Copyright (c) 1982, 1986, 1991, 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   *	@(#)subr_xxx.c	8.1 (Berkeley) 6/10/93
   */
  
  /*
   * Miscellaneous trivial functions, including many
   * that are often inline-expanded or done in assembler.
   */
  #include <sys/param.h>
  #include <sys/systm.h>
  #include <sys/conf.h>
  #include <sys/smr.h>
  
  
  /*
   * Unsupported device function (e.g. writing to read-only device).
   */
  int
  enodev(void)
  {
  
  	return (ENODEV);
  }
  
  /*
   * Unconfigured device function; driver not configured.
   */
  int
  enxio(void)
  {
  
  	return (ENXIO);
  }
  
  /*
   * Unsupported ioctl function.
   */
  int
  enoioctl(void)
  {
  
  	return (ENOTTY);
  }
  
  /*
   * Unsupported system function.
   * This is used for an otherwise-reasonable operation
   * that is not supported by the current system binary.
   */
  int
  enosys(void)
  {
  
  	return (ENOSYS);
  }
  
  /*
   * Return error for operation not supported
   * on a specific object or file type.
   */
  int
  eopnotsupp(void *v)
  {
  
  	return (EOPNOTSUPP);
  }
  
  /*
   * Generic null operation, always returns success.
   */
  int
  nullop(void *v)
  {
  
  	return (0);
  }
  
  struct bdevsw *
  bdevsw_lookup(dev_t dev)
  {
  	return (&bdevsw[major(dev)]);
  }
  
  struct cdevsw *
  cdevsw_lookup(dev_t dev)
  {
  	return (&cdevsw[major(dev)]);
  }
  
  /*
   * Convert a character device number to a block device number.
   */
  dev_t
  chrtoblk(dev_t dev)
  {
  	int blkmaj;
  
  	if (major(dev) >= nchrdev || major(dev) >= nchrtoblktbl)
  		return (NODEV);
  	blkmaj = chrtoblktbl[major(dev)];
  	if (blkmaj == NODEV)
  		return (NODEV);
  	return (makedev(blkmaj, minor(dev)));
  }
  
  /*
   * Convert a block device number to a character device number.
   */
  dev_t
  blktochr(dev_t dev)
  {
  	int blkmaj = major(dev);
  	int i;
  
  	if (blkmaj >= nblkdev)
  		return (NODEV);
  	for (i = 0; i < nchrtoblktbl; i++)
  		if (blkmaj == chrtoblktbl[i])
  			return (makedev(i, minor(dev)));
  	return (NODEV);
  }
  
  /*
   * Check that we're in a context where it's okay to sleep.
   */
  void
  assertwaitok(void)
  {
  	if (panicstr || db_active)
  		return;
  
  	splassert(IPL_NONE);
  	SMR_ASSERT_NONCRITICAL();
  #ifdef DIAGNOSTIC
  	if (curcpu()->ci_mutex_level != 0)
  		panic("assertwaitok: non-zero mutex count: %d",
  		    curcpu()->ci_mutex_level);
  #endif
  }