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linux-next/drivers/block/cciss_scsi.h
Stephen M. Cameron 8a4ec67bd5 cciss: add cciss_tape_cmds module paramter
This is to allow number of commands reserved for use by SCSI tape drives
and medium changers to be adjusted at driver load time via the kernel
parameter cciss_tape_cmds, with a default value of 6, and a range
of 2 - 16 inclusive.  Previously, the driver limited the number of
commands which could be queued to the SCSI half of the the driver
to only 2.  This is to fix the problem that if you had more than
two tape drives, you couldn't, for example, erase or rewind them all
at the same time.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-05-06 08:23:59 -06:00

80 lines
3.0 KiB
C

/*
* Disk Array driver for HP Smart Array controllers, SCSI Tape module.
* (C) Copyright 2001, 2007 Hewlett-Packard Development Company, L.P.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 300, Boston, MA
* 02111-1307, USA.
*
* Questions/Comments/Bugfixes to iss_storagedev@hp.com
*
*/
#ifdef CONFIG_CISS_SCSI_TAPE
#ifndef _CCISS_SCSI_H_
#define _CCISS_SCSI_H_
#include <scsi/scsicam.h> /* possibly irrelevant, since we don't show disks */
/* the scsi id of the adapter... */
#define SELF_SCSI_ID 15
/* 15 is somewhat arbitrary, since the scsi-2 bus
that's presented by the driver to the OS is
fabricated. The "real" scsi-3 bus the
hardware presents is fabricated too.
The actual, honest-to-goodness physical
bus that the devices are attached to is not
addressible natively, and may in fact turn
out to be not scsi at all. */
/*
If the upper scsi layer tries to track how many commands we have
outstanding, it will be operating under the misapprehension that it is
the only one sending us requests. We also have the block interface,
which is where most requests must surely come from, so the upper layer's
notion of how many requests we have outstanding will be wrong most or
all of the time.
Note, the normal SCSI mid-layer error handling doesn't work well
for this driver because 1) it takes the io_request_lock before
calling error handlers and uses a local variable to store flags,
so the io_request_lock cannot be released and interrupts enabled
inside the error handlers, and, the error handlers cannot poll
for command completion because they might get commands from the
block half of the driver completing, and not know what to do
with them. That's what we get for making a hybrid scsi/block
driver, I suppose.
*/
struct cciss_scsi_dev_t {
int devtype;
int bus, target, lun; /* as presented to the OS */
unsigned char scsi3addr[8]; /* as presented to the HW */
unsigned char device_id[16]; /* from inquiry pg. 0x83 */
unsigned char vendor[8]; /* bytes 8-15 of inquiry data */
unsigned char model[16]; /* bytes 16-31 of inquiry data */
unsigned char revision[4]; /* bytes 32-35 of inquiry data */
};
struct cciss_scsi_hba_t {
char *name;
int ndevices;
#define CCISS_MAX_SCSI_DEVS_PER_HBA 16
struct cciss_scsi_dev_t dev[CCISS_MAX_SCSI_DEVS_PER_HBA];
};
#endif /* _CCISS_SCSI_H_ */
#endif /* CONFIG_CISS_SCSI_TAPE */