linux/drivers/scsi/st.h

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#ifndef _ST_H
#define _ST_H
#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/kref.h>
#include <scsi/scsi_cmnd.h>
/* Descriptor for analyzed sense data */
struct st_cmdstatus {
int midlevel_result;
struct scsi_sense_hdr sense_hdr;
int have_sense;
u64 uremainder64;
u8 flags;
u8 remainder_valid;
u8 fixed_format;
u8 deferred;
};
struct scsi_tape;
/* scsi tape command */
struct st_request {
unsigned char cmd[MAX_COMMAND_SIZE];
unsigned char sense[SCSI_SENSE_BUFFERSIZE];
int result;
struct scsi_tape *stp;
struct completion *waiting;
};
/* The tape buffer descriptor. */
struct st_buffer {
unsigned char dma; /* DMA-able buffer */
unsigned char do_dio; /* direct i/o set up? */
int buffer_size;
int buffer_blocks;
int buffer_bytes;
int read_pointer;
int writing;
int syscall_result;
struct st_request *last_SRpnt;
struct st_cmdstatus cmdstat;
unsigned char *b_data;
unsigned short use_sg; /* zero or max number of s/g segments for this adapter */
unsigned short sg_segs; /* number of segments in s/g list */
unsigned short orig_frp_segs; /* number of segments allocated at first try */
unsigned short frp_segs; /* number of buffer segments */
unsigned int frp_sg_current; /* driver buffer length currently in s/g list */
struct st_buf_fragment *frp; /* the allocated buffer fragment list */
struct scatterlist sg[1]; /* MUST BE last item */
};
/* The tape buffer fragment descriptor */
struct st_buf_fragment {
struct page *page;
unsigned int length;
};
/* The tape mode definition */
struct st_modedef {
unsigned char defined;
unsigned char sysv; /* SYS V semantics? */
unsigned char do_async_writes;
unsigned char do_buffer_writes;
unsigned char do_read_ahead;
unsigned char defaults_for_writes;
unsigned char default_compression; /* 0 = don't touch, etc */
short default_density; /* Forced density, -1 = no value */
int default_blksize; /* Forced blocksize, -1 = no value */
struct cdev *cdevs[2]; /* Auto-rewind and non-rewind devices */
};
/* Number of modes can be changed by changing ST_NBR_MODE_BITS. The maximum
number of modes is 16 (ST_NBR_MODE_BITS 4) */
#define ST_NBR_MODE_BITS 2
#define ST_NBR_MODES (1 << ST_NBR_MODE_BITS)
#define ST_MODE_SHIFT (7 - ST_NBR_MODE_BITS)
#define ST_MODE_MASK ((ST_NBR_MODES - 1) << ST_MODE_SHIFT)
#define ST_MAX_TAPES 128
#define ST_MAX_TAPE_ENTRIES (ST_MAX_TAPES << (ST_NBR_MODE_BITS + 1))
/* The status related to each partition */
struct st_partstat {
unsigned char rw;
unsigned char eof;
unsigned char at_sm;
unsigned char last_block_valid;
u32 last_block_visited;
int drv_block; /* The block where the drive head is */
int drv_file;
};
#define ST_NBR_PARTITIONS 4
/* The tape drive descriptor */
struct scsi_tape {
struct scsi_driver *driver;
struct scsi_device *device;
struct mutex lock; /* For serialization */
struct completion wait; /* For SCSI commands */
struct st_buffer *buffer;
/* Drive characteristics */
unsigned char omit_blklims;
unsigned char do_auto_lock;
unsigned char can_bsr;
unsigned char can_partitions;
unsigned char two_fm;
unsigned char fast_mteom;
unsigned char immediate;
unsigned char restr_dma;
unsigned char scsi2_logical;
unsigned char default_drvbuffer; /* 0xff = don't touch, value 3 bits */
unsigned char cln_mode; /* 0 = none, otherwise sense byte nbr */
unsigned char cln_sense_value;
unsigned char cln_sense_mask;
unsigned char use_pf; /* Set Page Format bit in all mode selects? */
[SCSI] st: fix Tape dies if wrong block size used, bug 7919 On Thu, 1 Feb 2007, Andrew Morton wrote: > On Thu, 1 Feb 2007 15:34:29 -0800 > bugme-daemon@bugzilla.kernel.org wrote: > > > http://bugzilla.kernel.org/show_bug.cgi?id=7919 > > > > Summary: Tape dies if wrong block size used > > Kernel Version: 2.6.20-rc5 > > Status: NEW > > Severity: normal > > Owner: scsi_drivers-other@kernel-bugs.osdl.org > > Submitter: dmartin@sccd.ctc.edu > > > > > > Most recent kernel where this bug did *NOT* occur: 2.6.17.14 > > > > Other Kernels Tested and Results: > > > > OK 2.6.15.7 > > OK 2.6.16.37 > > OK 2.6.17.14 > > BAD 2.6.18.6 > > BAD 2.6.18-1.2869.fc6 > > BAD 2.6.19.2 + > > BAD 2.6.20-rc5 > > > > NOTE: 2.6.18-1.2869.fc6 is a Fedora modified kernel, all others are from kernel.org > > ... > > Steps to reproduce: > > Get a Adaptec AHA-2940U/UW/D / AIC-7881U card and a tape drive, > > install a recent kernel > > set the tape block size - mt setblk 4096 > > read from or write to tape using wrong block size - tar -b 7 -cvf /dev/tape foo > > Write does not trigger this bug because the driver refuses in fixed block mode writes that are not a multiple of the block size. Read does trigger it in my system. The bug is not associated with any specific HBA. st tries to do direct i/o in fixed block mode with reads that are not a multiple of tape block size. The patch in this message fixes the st problem by switching to using the driver buffer up to the next close of the device file in fixed block mode if the user asks for a read like this. I don't know why the bug has surfaced only after 2.6.17 although the st problem is old. There may be another bug in the block subsystem and this patch works around it. However, the patch fixes a problem in st and in this way it is a valid fix. This patch may also fix the bug 7900. The patch compiles and is lightly tested. Signed-off-by: Kai Makisara <kai.makisara@kolumbus.fi> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2007-02-03 11:21:29 +00:00
unsigned char try_dio; /* try direct i/o in general? */
unsigned char try_dio_now; /* try direct i/o before next close? */
unsigned char c_algo; /* compression algorithm */
unsigned char pos_unknown; /* after reset position unknown */
int tape_type;
int long_timeout; /* timeout for commands known to take long time */
unsigned long max_pfn; /* the maximum page number reachable by the HBA */
/* Mode characteristics */
struct st_modedef modes[ST_NBR_MODES];
int current_mode;
/* Status variables */
int partition;
int new_partition;
int nbr_partitions; /* zero until partition support enabled */
struct st_partstat ps[ST_NBR_PARTITIONS];
unsigned char dirty;
unsigned char ready;
unsigned char write_prot;
unsigned char drv_write_prot;
unsigned char in_use;
unsigned char blksize_changed;
unsigned char density_changed;
unsigned char compression_changed;
unsigned char drv_buffer;
unsigned char density;
unsigned char door_locked;
unsigned char autorew_dev; /* auto-rewind device */
unsigned char rew_at_close; /* rewind necessary at close */
unsigned char inited;
unsigned char cleaning_req; /* cleaning requested? */
int block_size;
int min_block;
int max_block;
int recover_count; /* From tape opening */
int recover_reg; /* From last status call */
#if DEBUG
unsigned char write_pending;
int nbr_finished;
int nbr_waits;
int nbr_requests;
int nbr_dio;
int nbr_pages;
int nbr_combinable;
unsigned char last_cmnd[6];
unsigned char last_sense[16];
#endif
struct gendisk *disk;
struct kref kref;
};
/* Bit masks for use_pf */
#define USE_PF 1
#define PF_TESTED 2
/* Values of eof */
#define ST_NOEOF 0
#define ST_FM_HIT 1
#define ST_FM 2
#define ST_EOM_OK 3
#define ST_EOM_ERROR 4
#define ST_EOD_1 5
#define ST_EOD_2 6
#define ST_EOD 7
/* EOD hit while reading => ST_EOD_1 => return zero => ST_EOD_2 =>
return zero => ST_EOD, return ENOSPC */
/* When writing: ST_EOM_OK == early warning found, write OK
ST_EOD_1 == allow trying new write after early warning
ST_EOM_ERROR == early warning found, not able to write all */
/* Values of rw */
#define ST_IDLE 0
#define ST_READING 1
#define ST_WRITING 2
/* Values of ready state */
#define ST_READY 0
#define ST_NOT_READY 1
#define ST_NO_TAPE 2
/* Values for door lock state */
#define ST_UNLOCKED 0
#define ST_LOCKED_EXPLICIT 1
#define ST_LOCKED_AUTO 2
#define ST_LOCK_FAILS 3
/* Positioning SCSI-commands for Tandberg, etc. drives */
#define QFA_REQUEST_BLOCK 0x02
#define QFA_SEEK_BLOCK 0x0c
/* Setting the binary options */
#define ST_DONT_TOUCH 0
#define ST_NO 1
#define ST_YES 2
#define EXTENDED_SENSE_START 18
/* Masks for some conditions in the sense data */
#define SENSE_FMK 0x80
#define SENSE_EOM 0x40
#define SENSE_ILI 0x20
#endif