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Diffstat (limited to 'drivers/scsi/osst_options.h')
| -rw-r--r-- | drivers/scsi/osst_options.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/drivers/scsi/osst_options.h b/drivers/scsi/osst_options.h new file mode 100644 index 000000000..a6a389b88 --- /dev/null +++ b/drivers/scsi/osst_options.h @@ -0,0 +1,107 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + The compile-time configurable defaults for the Linux SCSI tape driver. + + Copyright 1995 Kai Makisara. + + Last modified: Wed Sep 2 21:24:07 1998 by root@home + + Changed (and renamed) for OnStream SCSI drives garloff@suse.de + 2000-06-21 + + $Header: /cvsroot/osst/Driver/osst_options.h,v 1.6 2003/12/23 14:22:12 wriede Exp $ +*/ + +#ifndef _OSST_OPTIONS_H +#define _OSST_OPTIONS_H + +/* The minimum limit for the number of SCSI tape devices is determined by + OSST_MAX_TAPES. If the number of tape devices and the "slack" defined by + OSST_EXTRA_DEVS exceeds OSST_MAX_TAPES, the large number is used. */ +#define OSST_MAX_TAPES 4 + +/* If OSST_IN_FILE_POS is nonzero, the driver positions the tape after the + record been read by the user program even if the tape has moved further + because of buffered reads. Should be set to zero to support also drives + that can't space backwards over records. NOTE: The tape will be + spaced backwards over an "accidentally" crossed filemark in any case. */ +#define OSST_IN_FILE_POS 1 + +/* The tape driver buffer size in kilobytes. */ +/* Don't change, as this is the HW blocksize */ +#define OSST_BUFFER_BLOCKS 32 + +/* The number of kilobytes of data in the buffer that triggers an + asynchronous write in fixed block mode. See also OSST_ASYNC_WRITES + below. */ +#define OSST_WRITE_THRESHOLD_BLOCKS 32 + +/* OSST_EOM_RESERVE defines the number of frames are kept in reserve for + * * write error recovery when writing near end of medium. ENOSPC is returned + * * when write() is called and the tape write position is within this number + * * of blocks from the tape capacity. */ +#define OSST_EOM_RESERVE 300 + +/* The maximum number of tape buffers the driver allocates. The number + is also constrained by the number of drives detected. Determines the + maximum number of concurrently active tape drives. */ +#define OSST_MAX_BUFFERS OSST_MAX_TAPES + +/* Maximum number of scatter/gather segments */ +/* Fit one buffer in pages and add one for the AUX header */ +#define OSST_MAX_SG (((OSST_BUFFER_BLOCKS*1024) / PAGE_SIZE) + 1) + +/* The number of scatter/gather segments to allocate at first try (must be + smaller or equal to the maximum). */ +#define OSST_FIRST_SG ((OSST_BUFFER_BLOCKS*1024) / PAGE_SIZE) + +/* The size of the first scatter/gather segments (determines the maximum block + size for SCSI adapters not supporting scatter/gather). The default is set + to try to allocate the buffer as one chunk. */ +#define OSST_FIRST_ORDER (15-PAGE_SHIFT) + + +/* The following lines define defaults for properties that can be set + separately for each drive using the MTSTOPTIONS ioctl. */ + +/* If OSST_TWO_FM is non-zero, the driver writes two filemarks after a + file being written. Some drives can't handle two filemarks at the + end of data. */ +#define OSST_TWO_FM 0 + +/* If OSST_BUFFER_WRITES is non-zero, writes in fixed block mode are + buffered until the driver buffer is full or asynchronous write is + triggered. */ +#define OSST_BUFFER_WRITES 1 + +/* If OSST_ASYNC_WRITES is non-zero, the SCSI write command may be started + without waiting for it to finish. May cause problems in multiple + tape backups. */ +#define OSST_ASYNC_WRITES 1 + +/* If OSST_READ_AHEAD is non-zero, blocks are read ahead in fixed block + mode. */ +#define OSST_READ_AHEAD 1 + +/* If OSST_AUTO_LOCK is non-zero, the drive door is locked at the first + read or write command after the device is opened. The door is opened + when the device is closed. */ +#define OSST_AUTO_LOCK 0 + +/* If OSST_FAST_MTEOM is non-zero, the MTEOM ioctl is done using the + direct SCSI command. The file number status is lost but this method + is fast with some drives. Otherwise MTEOM is done by spacing over + files and the file number status is retained. */ +#define OSST_FAST_MTEOM 0 + +/* If OSST_SCSI2LOGICAL is nonzero, the logical block addresses are used for + MTIOCPOS and MTSEEK by default. Vendor addresses are used if OSST_SCSI2LOGICAL + is zero. */ +#define OSST_SCSI2LOGICAL 0 + +/* If OSST_SYSV is non-zero, the tape behaves according to the SYS V semantics. + The default is BSD semantics. */ +#define OSST_SYSV 0 + + +#endif |