549 lines
12 KiB
C
549 lines
12 KiB
C
/* $NetBSD: ramdisk.c,v 1.10 1996/10/13 01:37:07 christos Exp $ */
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/*
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* Copyright (c) 1995 Gordon W. Ross, Leo Weppelman.
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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. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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* 4. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by
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* Gordon W. Ross and Leo Weppelman.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* This implements a general-puspose RAM-disk.
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* See ramdisk.h for notes on the config types.
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*
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* Note that this driver provides the same functionality
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* as the MFS filesystem hack, but this is better because
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* you can use this for any filesystem type you'd like!
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*
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* Credit for most of the kmem ramdisk code goes to:
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* Leo Weppelman (atari) and Phil Nelson (pc532)
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* Credit for the ideas behind the "user space RAM" code goes
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* to the authors of the MFS implementation.
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/systm.h>
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#include <sys/buf.h>
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#include <sys/device.h>
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#include <sys/disk.h>
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#include <sys/proc.h>
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#include <sys/conf.h>
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#include <vm/vm.h>
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#include <vm/vm_kern.h>
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/* Don't want all those other VM headers... */
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extern vm_offset_t kmem_alloc __P((vm_map_t, vm_size_t));
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#include <dev/ramdisk.h>
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/*
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* By default, include the user-space functionality.
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* Use: option RAMDISK_SERVER=0 to turn it off.
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*/
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#ifndef RAMDISK_SERVER
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#define RAMDISK_SERVER 1
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#endif
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/*
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* XXX: the "control" unit is (base unit + 16).
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* We should just use the cdev as the "control", but
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* that interferes with the security stuff preventing
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* simulatneous use of raw and block devices.
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*
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* XXX Assumption: 16 RAM-disks are enough!
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*/
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#define RD_MAX_UNITS 0x10
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#define RD_IS_CTRL(unit) (unit & 0x10)
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#define RD_UNIT(unit) (unit & 0xF)
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/* autoconfig stuff... */
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struct rd_softc {
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struct device sc_dev; /* REQUIRED first entry */
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struct disk sc_dkdev; /* hook for generic disk handling */
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struct rd_conf sc_rd;
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struct buf *sc_buflist;
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int sc_flags;
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};
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/* shorthand for fields in sc_rd: */
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#define sc_addr sc_rd.rd_addr
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#define sc_size sc_rd.rd_size
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#define sc_type sc_rd.rd_type
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/* flags */
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#define RD_ISOPEN 0x01
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#define RD_SERVED 0x02
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void rdattach __P((int));
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static void rd_attach __P((struct device *, struct device *, void *));
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/*
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* Some ports (like i386) use a swapgeneric that wants to
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* snoop around in this rd_cd structure. It is preserved
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* (for now) to remain compatible with such practice.
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* XXX - that practice is questionable...
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*/
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struct cfdriver rd_cd = {
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NULL, "rd", DV_DULL, NULL, 0
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};
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void rdstrategy __P((struct buf *bp));
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struct dkdriver rddkdriver = { rdstrategy };
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static int ramdisk_ndevs;
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static void *ramdisk_devs[RD_MAX_UNITS];
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/*
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* This is called if we are configured as a pseudo-device
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*/
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void
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rdattach(n)
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int n;
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{
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struct rd_softc *sc;
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int i;
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#ifdef DIAGNOSTIC
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if (ramdisk_ndevs) {
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printf("ramdisk: multiple attach calls?\n");
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return;
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}
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#endif
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/* XXX: Are we supposed to provide a default? */
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if (n <= 1)
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n = 1;
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if (n > RD_MAX_UNITS)
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n = RD_MAX_UNITS;
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ramdisk_ndevs = n;
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/* XXX: Fake-up rd_cd (see above) */
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rd_cd.cd_ndevs = ramdisk_ndevs;
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rd_cd.cd_devs = ramdisk_devs;
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/* Attach as if by autoconfig. */
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for (i = 0; i < n; i++) {
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sc = malloc(sizeof(*sc), M_DEVBUF, M_WAITOK);
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if (!sc) {
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printf("ramdisk: malloc for attach failed!\n");
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return;
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}
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bzero((caddr_t)sc, sizeof(*sc));
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ramdisk_devs[i] = sc;
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sc->sc_dev.dv_unit = i;
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sprintf(sc->sc_dev.dv_xname, "rd%d", i);
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rd_attach(NULL, &sc->sc_dev, NULL);
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}
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}
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static void
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rd_attach(parent, self, aux)
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struct device *parent, *self;
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void *aux;
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{
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struct rd_softc *sc = (struct rd_softc *)self;
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/* XXX - Could accept aux info here to set the config. */
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#ifdef RAMDISK_HOOKS
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/*
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* This external function might setup a pre-loaded disk.
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* All it would need to do is setup the rd_conf struct.
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* See sys/arch/sun3/dev/rd_root.c for an example.
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*/
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rd_attach_hook(sc->sc_dev.dv_unit, &sc->sc_rd);
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#endif
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/*
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* Initialize and attach the disk structure.
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*/
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sc->sc_dkdev.dk_driver = &rddkdriver;
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sc->sc_dkdev.dk_name = sc->sc_dev.dv_xname;
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disk_attach(&sc->sc_dkdev);
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}
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/*
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* operational routines:
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* open, close, read, write, strategy,
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* ioctl, dump, size
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*/
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#if RAMDISK_SERVER
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static int rd_server_loop __P((struct rd_softc *sc));
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static int rd_ioctl_server __P((struct rd_softc *sc,
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struct rd_conf *urd, struct proc *proc));
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#endif
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static int rd_ioctl_kalloc __P((struct rd_softc *sc,
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struct rd_conf *urd, struct proc *proc));
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dev_type_open(rdopen);
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dev_type_close(rdclose);
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dev_type_read(rdread);
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dev_type_write(rdwrite);
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dev_type_ioctl(rdioctl);
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dev_type_size(rdsize);
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dev_type_dump(rddump);
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int rddump(dev, blkno, va, size)
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dev_t dev;
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daddr_t blkno;
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caddr_t va;
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size_t size;
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{
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return ENODEV;
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}
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int rdsize(dev_t dev)
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{
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int unit;
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struct rd_softc *sc;
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/* Disallow control units. */
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unit = minor(dev);
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if (unit >= ramdisk_ndevs)
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return 0;
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sc = ramdisk_devs[unit];
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if (sc == NULL)
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return 0;
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if (sc->sc_type == RD_UNCONFIGURED)
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return 0;
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return (sc->sc_size >> DEV_BSHIFT);
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}
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int
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rdopen(dev, flag, fmt, proc)
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dev_t dev;
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int flag, fmt;
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struct proc *proc;
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{
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int md, unit;
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struct rd_softc *sc;
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md = minor(dev);
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unit = RD_UNIT(md);
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if (unit >= ramdisk_ndevs)
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return ENXIO;
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sc = ramdisk_devs[unit];
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if (sc == NULL)
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return ENXIO;
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/*
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* The control device is not exclusive, and can
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* open uninitialized units (so you can setconf).
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*/
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if (RD_IS_CTRL(md))
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return 0;
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#ifdef RAMDISK_HOOKS
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/* Call the open hook to allow loading the device. */
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rd_open_hook(unit, &sc->sc_rd);
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#endif
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/*
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* This is a normal, "slave" device, so
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* enforce initialized, exclusive open.
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*/
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if (sc->sc_type == RD_UNCONFIGURED)
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return ENXIO;
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if (sc->sc_flags & RD_ISOPEN)
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return EBUSY;
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return 0;
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}
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int
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rdclose(dev, flag, fmt, proc)
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dev_t dev;
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int flag, fmt;
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struct proc *proc;
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{
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int md, unit;
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struct rd_softc *sc;
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md = minor(dev);
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unit = RD_UNIT(md);
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sc = ramdisk_devs[unit];
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if (RD_IS_CTRL(md))
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return 0;
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/* Normal device. */
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sc->sc_flags = 0;
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return 0;
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}
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int
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rdread(dev, uio, flags)
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dev_t dev;
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struct uio *uio;
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int flags;
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{
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return (physio(rdstrategy, NULL, dev, B_READ, minphys, uio));
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}
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int
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rdwrite(dev, uio, flags)
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dev_t dev;
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struct uio *uio;
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int flags;
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{
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return (physio(rdstrategy, NULL, dev, B_WRITE, minphys, uio));
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}
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/*
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* Handle I/O requests, either directly, or
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* by passing them to the server process.
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*/
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void
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rdstrategy(bp)
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struct buf *bp;
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{
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int md, unit;
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struct rd_softc *sc;
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caddr_t addr;
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size_t off, xfer;
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md = minor(bp->b_dev);
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unit = RD_UNIT(md);
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sc = ramdisk_devs[unit];
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switch (sc->sc_type) {
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#if RAMDISK_SERVER
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case RD_UMEM_SERVER:
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/* Just add this job to the server's queue. */
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bp->b_actf = sc->sc_buflist;
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sc->sc_buflist = bp;
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if (bp->b_actf == NULL) {
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/* server queue was empty. */
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wakeup((caddr_t)sc);
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/* see rd_server_loop() */
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}
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/* no biodone in this case */
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return;
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#endif /* RAMDISK_SERVER */
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case RD_KMEM_FIXED:
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case RD_KMEM_ALLOCATED:
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/* These are in kernel space. Access directly. */
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bp->b_resid = bp->b_bcount;
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off = (bp->b_blkno << DEV_BSHIFT);
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if (off >= sc->sc_size) {
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if (bp->b_flags & B_READ)
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break; /* EOF */
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goto set_eio;
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}
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xfer = bp->b_resid;
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if (xfer > (sc->sc_size - off))
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xfer = (sc->sc_size - off);
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addr = sc->sc_addr + off;
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if (bp->b_flags & B_READ)
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bcopy(addr, bp->b_data, xfer);
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else
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bcopy(bp->b_data, addr, xfer);
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bp->b_resid -= xfer;
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break;
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default:
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bp->b_resid = bp->b_bcount;
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set_eio:
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bp->b_error = EIO;
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bp->b_flags |= B_ERROR;
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break;
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}
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biodone(bp);
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}
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int
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rdioctl(dev, cmd, data, flag, proc)
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dev_t dev;
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u_long cmd;
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int flag;
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caddr_t data;
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struct proc *proc;
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{
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int md, unit;
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struct rd_softc *sc;
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struct rd_conf *urd;
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md = minor(dev);
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unit = RD_UNIT(md);
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sc = ramdisk_devs[unit];
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/* If this is not the control device, punt! */
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if (RD_IS_CTRL(md) == 0)
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return ENOTTY;
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urd = (struct rd_conf *)data;
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switch (cmd) {
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case RD_GETCONF:
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*urd = sc->sc_rd;
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return 0;
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case RD_SETCONF:
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/* Can only set it once. */
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if (sc->sc_type != RD_UNCONFIGURED)
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break;
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switch (urd->rd_type) {
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case RD_KMEM_ALLOCATED:
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return rd_ioctl_kalloc(sc, urd, proc);
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#if RAMDISK_SERVER
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case RD_UMEM_SERVER:
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return rd_ioctl_server(sc, urd, proc);
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#endif
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default:
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break;
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}
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break;
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}
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return EINVAL;
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}
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/*
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* Handle ioctl RD_SETCONF for (sc_type == RD_KMEM_ALLOCATED)
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* Just allocate some kernel memory and return.
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*/
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static int
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rd_ioctl_kalloc(sc, urd, proc)
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struct rd_softc *sc;
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struct rd_conf *urd;
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struct proc *proc;
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{
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vm_offset_t addr;
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vm_size_t size;
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/* Sanity check the size. */
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size = urd->rd_size;
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addr = kmem_alloc(kernel_map, size);
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if (!addr)
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return ENOMEM;
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/* This unit is now configured. */
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sc->sc_addr = (caddr_t)addr; /* kernel space */
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sc->sc_size = (size_t)size;
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sc->sc_type = RD_KMEM_ALLOCATED;
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return 0;
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}
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#if RAMDISK_SERVER
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/*
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* Handle ioctl RD_SETCONF for (sc_type == RD_UMEM_SERVER)
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* Set config, then become the I/O server for this unit.
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*/
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static int
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rd_ioctl_server(sc, urd, proc)
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struct rd_softc *sc;
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struct rd_conf *urd;
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struct proc *proc;
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{
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vm_offset_t end;
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int error;
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/* Sanity check addr, size. */
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end = (vm_offset_t) (urd->rd_addr + urd->rd_size);
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if ((end >= VM_MAXUSER_ADDRESS) ||
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(end < ((vm_offset_t) urd->rd_addr)) )
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return EINVAL;
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/* This unit is now configured. */
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sc->sc_addr = urd->rd_addr; /* user space */
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sc->sc_size = urd->rd_size;
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sc->sc_type = RD_UMEM_SERVER;
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/* Become the server daemon */
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error = rd_server_loop(sc);
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/* This server is now going away! */
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sc->sc_type = RD_UNCONFIGURED;
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sc->sc_addr = 0;
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sc->sc_size = 0;
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return (error);
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}
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int rd_sleep_pri = PWAIT | PCATCH;
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static int
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rd_server_loop(sc)
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struct rd_softc *sc;
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{
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struct buf *bp;
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caddr_t addr; /* user space address */
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size_t off; /* offset into "device" */
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size_t xfer; /* amount to transfer */
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int error;
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for (;;) {
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/* Wait for some work to arrive. */
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while (sc->sc_buflist == NULL) {
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error = tsleep((caddr_t)sc, rd_sleep_pri, "rd_idle", 0);
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if (error)
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return error;
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}
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/* Unlink buf from head of list. */
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bp = sc->sc_buflist;
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sc->sc_buflist = bp->b_actf;
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bp->b_actf = NULL;
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/* Do the transfer to/from user space. */
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error = 0;
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bp->b_resid = bp->b_bcount;
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off = (bp->b_blkno << DEV_BSHIFT);
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if (off >= sc->sc_size) {
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if (bp->b_flags & B_READ)
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goto done; /* EOF (not an error) */
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error = EIO;
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goto done;
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}
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xfer = bp->b_resid;
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if (xfer > (sc->sc_size - off))
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xfer = (sc->sc_size - off);
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addr = sc->sc_addr + off;
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if (bp->b_flags & B_READ)
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error = copyin(addr, bp->b_data, xfer);
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else
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error = copyout(bp->b_data, addr, xfer);
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if (!error)
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bp->b_resid -= xfer;
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done:
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if (error) {
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bp->b_error = error;
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bp->b_flags |= B_ERROR;
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}
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biodone(bp);
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}
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}
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#endif /* RAMDISK_SERVER */
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