> Date: Mon, 25 Apr 94 16:13:50 -0600
> From: mike@cs.utah.edu (Mike Hibler)
> 
> In 4.4 Lite (shipping now!) the /dev/zero mmap hack has been elevated to
> machine independent status.  It uses a function, iszerodev(dev_t) defined
> in conf.c, to make the determination.
> 
> Mike

OK, a function is fine with me.  Will the 4.4 Lite changes be there
soon?  If not, I'd like to put in the new iszerodev(dev_t) function.

Here are the changes re-done using iszerodev(dev_t):

diff -c compat/sunos/sun_misc.c.orig compat/sunos/sun_misc.c
*** compat/sunos/sun_misc.c.orig	Mon Apr 25 06:27:24 1994
--- compat/sunos/sun_misc.c	Tue Apr 26 10:36:22 1994
***************
*** 404,415 ****
  	return (error);
  }
  
- #if defined(sparc)
- #define	DEVZERO	makedev(3, 12)		/* major,minor of /dev/zero */
- #else /* all m68k architectures */
- #define	DEVZERO	makedev(2, 12)		/* major,minor of /dev/zero */
- #endif
- 
  #define	SUN__MAP_NEW	0x80000000	/* if not, old mmap & cannot handle */
  
  struct sun_mmap_args {
--- 404,409 ----
***************
*** 453,459 ****
  	    (fp = fdp->fd_ofiles[uap->fd]) != NULL &&			/*XXX*/
  	    fp->f_type == DTYPE_VNODE &&				/*XXX*/
  	    (vp = (struct vnode *)fp->f_data)->v_type == VCHR &&	/*XXX*/
! 	    vp->v_rdev == DEVZERO) {					/*XXX*/
  		uap->flags |= MAP_ANON;
  		uap->fd = -1;
  	}
--- 447,453 ----
  	    (fp = fdp->fd_ofiles[uap->fd]) != NULL &&			/*XXX*/
  	    fp->f_type == DTYPE_VNODE &&				/*XXX*/
  	    (vp = (struct vnode *)fp->f_data)->v_type == VCHR &&	/*XXX*/
! 	    iszerodev(vp->v_rdev) {					/*XXX*/
  		uap->flags |= MAP_ANON;
  		uap->fd = -1;
  	}
diff -c arch/sun3/sun3/conf.c.orig arch/sun3/sun3/conf.c
*** arch/sun3/sun3/conf.c.orig	Tue Mar  1 06:21:50 1994
--- arch/sun3/sun3/conf.c	Tue Apr 26 10:41:56 1994
***************
*** 255,261 ****
--- 255,266 ----
  
  int	nchrdev = sizeof (cdevsw) / sizeof (cdevsw[0]);
  
+ /* I'd like to change this to 3 for SunOS 4.1.1 compatibility. -gwr */
  int	mem_no = 2; 	/* major device number of memory special file */
+ int iszerodev(dev_t dev)
+ {
+     return(dev == makedev(mem_no, 12));
+ }
  
  /*
   * Swapdev is a fake device implemented
diff -c arch/sparc/sparc/conf.c.orig arch/sparc/sparc/conf.c
*** arch/sparc/sparc/conf.c.orig	Thu Mar  3 05:57:16 1994
--- arch/sparc/sparc/conf.c	Tue Apr 26 10:43:08 1994
***************
*** 430,435 ****
--- 430,439 ----
  int	nchrdev = sizeof (cdevsw) / sizeof (cdevsw[0]);
  
  int	mem_no = 3; 	/* major device number of memory special file */
+ int iszerodev(dev_t dev)
+ {
+     return(dev == makedev(mem_no, 12));
+ }
  
  /*
   * Swapdev is a fake device implemented
diff -c arch/amiga/amiga/conf.c.orig arch/amiga/amiga/conf.c
*** arch/amiga/amiga/conf.c.orig	Wed Apr  6 06:16:01 1994
--- arch/amiga/amiga/conf.c	Tue Apr 26 10:44:06 1994
***************
*** 416,421 ****
--- 416,425 ----
  #endif
  
  int	mem_no = 2; 	/* major device number of memory special file */
+ int iszerodev(dev_t dev)
+ {
+     return(dev == makedev(mem_no, 12));
+ }
  
  /*
   * Swapdev is a fake device implemented
diff -c arch/mac68k/mac68k/conf.c.orig arch/mac68k/mac68k/conf.c
*** arch/mac68k/mac68k/conf.c.orig	Fri Feb  4 05:11:27 1994
--- arch/mac68k/mac68k/conf.c	Tue Apr 26 10:44:42 1994
***************
*** 363,368 ****
--- 363,372 ----
  int	nchrdev = sizeof (cdevsw) / sizeof (cdevsw[0]);
  
  int	mem_no = 2; 	/* major device number of memory special file */
+ int iszerodev(dev_t dev)
+ {
+     return(dev == makedev(mem_no, 12));
+ }
  
  /*
   * Swapdev is a fake device implemented

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