106 lines
3.9 KiB
C
106 lines
3.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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The compile-time configurable defaults for the Linux SCSI tape driver.
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Copyright 1995-2003 Kai Makisara.
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Last modified: Thu Feb 21 21:47:07 2008 by kai.makisara
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*/
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#ifndef _ST_OPTIONS_H
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#define _ST_OPTIONS_H
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/* If TRY_DIRECT_IO is non-zero, the driver tries to transfer data directly
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between the user buffer and tape drive. If this is not possible, driver
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buffer is used. If TRY_DIRECT_IO is zero, driver buffer is always used. */
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#define TRY_DIRECT_IO 1
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/* The driver does not wait for some operations to finish before returning
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to the user program if ST_NOWAIT is non-zero. This helps if the SCSI
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adapter does not support multiple outstanding commands. However, the user
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should not give a new tape command before the previous one has finished. */
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#define ST_NOWAIT 0
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/* If ST_IN_FILE_POS is nonzero, the driver positions the tape after the
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record been read by the user program even if the tape has moved further
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because of buffered reads. Should be set to zero to support also drives
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that can't space backwards over records. NOTE: The tape will be
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spaced backwards over an "accidentally" crossed filemark in any case. */
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#define ST_IN_FILE_POS 0
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/* If ST_RECOVERED_WRITE_FATAL is non-zero, recovered errors while writing
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are considered "hard errors". */
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#define ST_RECOVERED_WRITE_FATAL 0
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/* The "guess" for the block size for devices that don't support MODE
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SENSE. */
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#define ST_DEFAULT_BLOCK 0
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/* The minimum tape driver buffer size in kilobytes in fixed block mode.
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Must be non-zero. */
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#define ST_FIXED_BUFFER_BLOCKS 32
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/* Maximum number of scatter/gather segments */
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#define ST_MAX_SG 256
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/* The number of scatter/gather segments to allocate at first try (must be
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smaller or equal to the maximum). */
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#define ST_FIRST_SG 8
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/* The size of the first scatter/gather segments (determines the maximum block
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size for SCSI adapters not supporting scatter/gather). The default is set
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to try to allocate the buffer as one chunk. */
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#define ST_FIRST_ORDER 5
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/* The following lines define defaults for properties that can be set
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separately for each drive using the MTSTOPTIONS ioctl. */
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/* If ST_TWO_FM is non-zero, the driver writes two filemarks after a
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file being written. Some drives can't handle two filemarks at the
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end of data. */
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#define ST_TWO_FM 0
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/* If ST_BUFFER_WRITES is non-zero, writes in fixed block mode are
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buffered until the driver buffer is full or asynchronous write is
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triggered. May make detection of End-Of-Medium early enough fail. */
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#define ST_BUFFER_WRITES 1
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/* If ST_ASYNC_WRITES is non-zero, the SCSI write command may be started
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without waiting for it to finish. May cause problems in multiple
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tape backups. */
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#define ST_ASYNC_WRITES 1
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/* If ST_READ_AHEAD is non-zero, blocks are read ahead in fixed block
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mode. */
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#define ST_READ_AHEAD 1
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/* If ST_AUTO_LOCK is non-zero, the drive door is locked at the first
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read or write command after the device is opened. The door is opened
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when the device is closed. */
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#define ST_AUTO_LOCK 0
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/* If ST_FAST_MTEOM is non-zero, the MTEOM ioctl is done using the
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direct SCSI command. The file number status is lost but this method
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is fast with some drives. Otherwise MTEOM is done by spacing over
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files and the file number status is retained. */
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#define ST_FAST_MTEOM 0
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/* If ST_SCSI2LOGICAL is nonzero, the logical block addresses are used for
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MTIOCPOS and MTSEEK by default. Vendor addresses are used if ST_SCSI2LOGICAL
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is zero. */
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#define ST_SCSI2LOGICAL 0
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/* If ST_SYSV is non-zero, the tape behaves according to the SYS V semantics.
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The default is BSD semantics. */
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#define ST_SYSV 0
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/* If ST_SILI is non-zero, the SILI bit is set when reading in variable block
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mode and the block size is determined using the residual returned by the HBA. */
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#define ST_SILI 0
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/* Time to wait for the drive to become ready if blocking open */
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#define ST_BLOCK_SECONDS 120
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#endif
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