freebsd-dev/sys/scsi/scsi_driver.c
Tor Egge 7a1d27b301 Introduce an advisory exclusive lock on the scsi link structure.
Change sd_open, sd_close and sd_ioctl to use this lock to ensure
serialization of some critical operations, thus avoiding some
race conditions. Ideas picked from NetBSD (ccd and sd devices).
This fixes one of the problems noted in PR kern/3688.
Reviewed by:	"Justin T. Gibbs" <gibbs@plutotech.com>
1997-06-25 19:07:43 +00:00

257 lines
7.0 KiB
C

/*
* Copyright (C) 1995, HD Associates, Inc.
* PO Box 276
* Pepperell, MA 01463
* 508 433 5266
* dufault@hda.com
*
* This code is contributed to the University of California at Berkeley:
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*
* $Id: scsi_driver.c,v 1.23 1997/03/23 06:33:47 bde Exp $
*
*/
#include "opt_scsi.h"
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/malloc.h>
#include <sys/fcntl.h>
#include <scsi/scsi_all.h>
#include <scsi/scsiconf.h>
#include <scsi/scsi_debug.h>
#include <scsi/scsi_driver.h>
#define GETUNIT(DEVICE, DEV) \
((DEVICE)->getunit) ? (*(DEVICE)->getunit)((DEV)) \
: (minor((DEV)) & ~SCSI_CONTROL_MASK)
int
scsi_goaway(int force) /* XXX should do a lot more */
{
return 0;
}
/* scsi_device_attach: Attach a SCSI device. This routine will
* print out the device address, what it is, then call the type
* attach function and when that returns print a newline. If the
* type attach will make LOT's of noise it should print a leading
* newline and then the address using sc_print_addr. See "sd.c".
*/
int scsi_device_attach(struct scsi_link *sc_link)
{
errval errcode;
dev_t dev;
struct scsi_device *device = sc_link->device;
if (bootverbose)
sc_link->flags |= SDEV_BOOTVERBOSE;
SC_DEBUG(sc_link, SDEV_DB2,
("%s%dattach: ", device->name, sc_link->dev_unit));
/* Print _sane_ probe info! */
printf("%s%d at scbus%d target %d lun %d\n",
sc_link->device->name, sc_link->dev_unit,
sc_link->scsibus, sc_link->target, sc_link->lun);
#ifndef SCSIDEBUG
scsi_print_info(sc_link);
#endif
printf("%s%d: %s ", device->name, sc_link->dev_unit, device->desc);
/*
* XXX some SCSI adapter drivers print out things while the
* device-specific attach routine is running. The result is
* something of a mess. This hack at least keeps it so each
* line will begin with foodev0:.
*/
sc_print_init();
dev = scsi_dev_lookup(device->open);
sc_link->dev = (device->setunit ?
(*device->setunit)(dev, sc_link->dev_unit) :
makedev(major(dev), sc_link->dev_unit) );
errcode = (device->attach) ? (*(device->attach))(sc_link) : 0;
printf("\n");
sc_print_finish();
if (errcode == 0)
sc_link->flags |= device->link_flags;
return errcode;
}
int
scsi_open(dev_t dev, int flags, int fmt, struct proc *p,
struct scsi_device *device)
{
errval errcode;
u_int32_t unit;
struct scsi_link *sc_link;
if (device == 0)
return ENXIO;
unit = GETUNIT(device, dev);
sc_link = SCSI_LINK(device, unit);
/*
* Check the unit is legal
*/
if (sc_link == 0 || (sc_link->sd == 0 && !(sc_link->flags & SDEV_UK)))
return ENXIO;
/* If it is a "once only" device that is already open return EBUSY.
*/
if ((sc_link->flags & SDEV_ONCE_ONLY) && (sc_link->flags & SDEV_IS_OPEN))
return EBUSY;
/* For the control device (user ioctl's only) don't call the open
* entry.
*/
if (SCSI_CONTROL(dev) || (device->dev_open == 0))
{
scsi_test_unit_ready(sc_link, SCSI_SILENT);
errcode = 0;
}
else
errcode = (*device->dev_open)(dev, flags, fmt, p, sc_link);
if (!errcode ) sc_link->flags |= SDEV_IS_OPEN;
SC_DEBUG(sc_link, SDEV_DB1, ("%sopen: dev=0x%lx (unit %ld) result %d\n",
device->name, dev, unit, errcode));
return errcode;
}
int
scsi_close(dev_t dev, int flags, int fmt, struct proc *p,
struct scsi_device *device)
{
errval errcode;
struct scsi_link *sc_link = SCSI_LINK(device, GETUNIT(device, dev));
SC_DEBUG(sc_link, SDEV_DB1, ("%sclose: Closing device\n", device->name));
if (SCSI_CONTROL(dev) || (device->dev_close == 0))
errcode = 0;
else
errcode = (*device->dev_close)(dev, flags, fmt, p, sc_link);
sc_link->flags &= ~SDEV_IS_OPEN;
return errcode;
}
int
scsi_ioctl(dev_t dev, u_int32_t cmd, caddr_t arg, int flags, struct proc *p,
struct scsi_device *device)
{
errval errcode;
struct scsi_link *sc_link = SCSI_LINK(device, GETUNIT(device, dev));
if (SCSI_CONTROL(dev) || (device->dev_ioctl == 0))
errcode = scsi_do_ioctl(dev, cmd, arg, flags, p, sc_link);
else
errcode = (*device->dev_ioctl)(dev, cmd, arg, flags, p, sc_link);
return errcode;
}
void
scsi_minphys(struct buf *bp, struct scsi_device *device)
{
struct scsi_link *sc_link = SCSI_LINK(device, GETUNIT(device, bp->b_dev));
(*sc_link->adapter->scsi_minphys)(bp);
}
void
scsi_strategy(struct buf *bp, struct scsi_device *device)
{
u_int32_t unit = GETUNIT(device, bp->b_dev);
struct scsi_link *sc_link = SCSI_LINK(device, unit);
SC_DEBUG(sc_link, SDEV_DB2, ("\n%sstrategy ", device->name));
SC_DEBUG(sc_link, SDEV_DB1, ("%ld bytes @ blk%ld\n",
bp->b_bcount, bp->b_blkno));
if (SCSI_CONTROL(bp->b_dev) || (device->dev_strategy == 0))
{
bp->b_resid = bp->b_bcount;
bp->b_error = EIO;
bp->b_flags |= B_ERROR;
biodone(bp);
}
else
{
bp->b_resid = 0;
bp->b_error = 0;
if (bp->b_bcount == 0)
biodone(bp);
else
{
(*sc_link->adapter->scsi_minphys)(bp);
(*device->dev_strategy)(bp, sc_link);
}
}
}
int scsi_device_lock(struct scsi_link *sc_link)
{
int error;
while (sc_link->flags & SDEV_XLOCK) {
sc_link->flags |= SDEV_WANT;
error = tsleep(&sc_link->flags, PRIBIO | PCATCH, "sdevlk",0);
if (error)
return error;
}
sc_link->flags |= SDEV_XLOCK;
return 0;
}
void scsi_device_unlock(struct scsi_link *sc_link)
{
sc_link->flags &= ~SDEV_XLOCK;
if (sc_link->flags & SDEV_WANT) {
sc_link->flags &= ~SDEV_WANT;
wakeup(&sc_link->flags);
}
}