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linux-next/drivers/s390/char/tape.h
Michael Holzheu 5f38433885 [PATCH] s390: fix endless retry loop in tape driver 
If a tape device is assigned to another host, the interrupt for the assign
operation comes back with deferred condition code 1.  Under some conditions
this can lead to an endless loop of retries.  Check if the current request is
still in IO in deferred condition code handling and prevent retries when the
request has already been cancelled.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-24 07:33:18 -08:00

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/*
* drivers/s390/char/tape.h
* tape device driver for 3480/3490E/3590 tapes.
*
* S390 and zSeries version
* Copyright (C) 2001,2005 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Tuan Ngo-Anh <ngoanh@de.ibm.com>
* Martin Schwidefsky <schwidefsky@de.ibm.com>
* Stefan Bader <shbader@de.ibm.com>
*/
#ifndef _TAPE_H
#define _TAPE_H
#include <asm/ccwdev.h>
#include <asm/debug.h>
#include <asm/idals.h>
#include <linux/config.h>
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mtio.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
struct gendisk;
/*
* Define DBF_LIKE_HELL for lots of messages in the debug feature.
*/
#define DBF_LIKE_HELL
#ifdef DBF_LIKE_HELL
#define DBF_LH(level, str, ...) \
do { \
debug_sprintf_event(TAPE_DBF_AREA, level, str, ## __VA_ARGS__); \
} while (0)
#else
#define DBF_LH(level, str, ...) do {} while(0)
#endif
/*
* macros s390 debug feature (dbf)
*/
#define DBF_EVENT(d_level, d_str...) \
do { \
debug_sprintf_event(TAPE_DBF_AREA, d_level, d_str); \
} while (0)
#define DBF_EXCEPTION(d_level, d_str...) \
do { \
debug_sprintf_exception(TAPE_DBF_AREA, d_level, d_str); \
} while (0)
#define TAPE_VERSION_MAJOR 2
#define TAPE_VERSION_MINOR 0
#define TAPE_MAGIC "tape"
#define TAPE_MINORS_PER_DEV 2 /* two minors per device */
#define TAPEBLOCK_HSEC_SIZE 2048
#define TAPEBLOCK_HSEC_S2B 2
#define TAPEBLOCK_RETRIES 5
enum tape_medium_state {
MS_UNKNOWN,
MS_LOADED,
MS_UNLOADED,
MS_SIZE
};
enum tape_state {
TS_UNUSED=0,
TS_IN_USE,
TS_BLKUSE,
TS_INIT,
TS_NOT_OPER,
TS_SIZE
};
enum tape_op {
TO_BLOCK, /* Block read */
TO_BSB, /* Backward space block */
TO_BSF, /* Backward space filemark */
TO_DSE, /* Data security erase */
TO_FSB, /* Forward space block */
TO_FSF, /* Forward space filemark */
TO_LBL, /* Locate block label */
TO_NOP, /* No operation */
TO_RBA, /* Read backward */
TO_RBI, /* Read block information */
TO_RFO, /* Read forward */
TO_REW, /* Rewind tape */
TO_RUN, /* Rewind and unload tape */
TO_WRI, /* Write block */
TO_WTM, /* Write tape mark */
TO_MSEN, /* Medium sense */
TO_LOAD, /* Load tape */
TO_READ_CONFIG, /* Read configuration data */
TO_READ_ATTMSG, /* Read attention message */
TO_DIS, /* Tape display */
TO_ASSIGN, /* Assign tape to channel path */
TO_UNASSIGN, /* Unassign tape from channel path */
TO_SIZE /* #entries in tape_op_t */
};
/* Forward declaration */
struct tape_device;
/* tape_request->status can be: */
enum tape_request_status {
TAPE_REQUEST_INIT, /* request is ready to be processed */
TAPE_REQUEST_QUEUED, /* request is queued to be processed */
TAPE_REQUEST_IN_IO, /* request is currently in IO */
TAPE_REQUEST_DONE, /* request is completed. */
TAPE_REQUEST_CANCEL, /* request should be canceled. */
};
/* Tape CCW request */
struct tape_request {
struct list_head list; /* list head for request queueing. */
struct tape_device *device; /* tape device of this request */
struct ccw1 *cpaddr; /* address of the channel program. */
void *cpdata; /* pointer to ccw data. */
enum tape_request_status status;/* status of this request */
int options; /* options for execution. */
int retries; /* retry counter for error recovery. */
int rescnt; /* residual count from devstat. */
/* Callback for delivering final status. */
void (*callback)(struct tape_request *, void *);
void *callback_data;
enum tape_op op;
int rc;
};
/* Function type for magnetic tape commands */
typedef int (*tape_mtop_fn)(struct tape_device *, int);
/* Size of the array containing the mtops for a discipline */
#define TAPE_NR_MTOPS (MTMKPART+1)
/* Tape Discipline */
struct tape_discipline {
struct module *owner;
int (*setup_device)(struct tape_device *);
void (*cleanup_device)(struct tape_device *);
int (*irq)(struct tape_device *, struct tape_request *, struct irb *);
struct tape_request *(*read_block)(struct tape_device *, size_t);
struct tape_request *(*write_block)(struct tape_device *, size_t);
void (*process_eov)(struct tape_device*);
#ifdef CONFIG_S390_TAPE_BLOCK
/* Block device stuff. */
struct tape_request *(*bread)(struct tape_device *, struct request *);
void (*check_locate)(struct tape_device *, struct tape_request *);
void (*free_bread)(struct tape_request *);
#endif
/* ioctl function for additional ioctls. */
int (*ioctl_fn)(struct tape_device *, unsigned int, unsigned long);
/* Array of tape commands with TAPE_NR_MTOPS entries */
tape_mtop_fn *mtop_array;
};
/*
* The discipline irq function either returns an error code (<0) which
* means that the request has failed with an error or one of the following:
*/
#define TAPE_IO_SUCCESS 0 /* request successful */
#define TAPE_IO_PENDING 1 /* request still running */
#define TAPE_IO_RETRY 2 /* retry to current request */
#define TAPE_IO_STOP 3 /* stop the running request */
/* Char Frontend Data */
struct tape_char_data {
struct idal_buffer *idal_buf; /* idal buffer for user char data */
int block_size; /* of size block_size. */
};
#ifdef CONFIG_S390_TAPE_BLOCK
/* Block Frontend Data */
struct tape_blk_data
{
/* Block device request queue. */
request_queue_t * request_queue;
spinlock_t request_queue_lock;
/* Task to move entries from block request to CCS request queue. */
struct work_struct requeue_task;
atomic_t requeue_scheduled;
/* Current position on the tape. */
long block_position;
int medium_changed;
struct gendisk * disk;
};
#endif
/* Tape Info */
struct tape_device {
/* entry in tape_device_list */
struct list_head node;
int cdev_id;
struct ccw_device * cdev;
struct tape_class_device * nt;
struct tape_class_device * rt;
/* Device discipline information. */
struct tape_discipline * discipline;
void * discdata;
/* Generic status flags */
long tape_generic_status;
/* Device state information. */
wait_queue_head_t state_change_wq;
enum tape_state tape_state;
enum tape_medium_state medium_state;
unsigned char * modeset_byte;
/* Reference count. */
atomic_t ref_count;
/* Request queue. */
struct list_head req_queue;
/* Each tape device has (currently) two minor numbers. */
int first_minor;
/* Number of tapemarks required for correct termination. */
int required_tapemarks;
/* Block ID of the BOF */
unsigned int bof;
/* Character device frontend data */
struct tape_char_data char_data;
#ifdef CONFIG_S390_TAPE_BLOCK
/* Block dev frontend data */
struct tape_blk_data blk_data;
#endif
/* Function to start or stop the next request later. */
struct work_struct tape_dnr;
};
/* Externals from tape_core.c */
extern struct tape_request *tape_alloc_request(int cplength, int datasize);
extern void tape_free_request(struct tape_request *);
extern int tape_do_io(struct tape_device *, struct tape_request *);
extern int tape_do_io_async(struct tape_device *, struct tape_request *);
extern int tape_do_io_interruptible(struct tape_device *, struct tape_request *);
extern int tape_cancel_io(struct tape_device *, struct tape_request *);
void tape_hotplug_event(struct tape_device *, int major, int action);
static inline int
tape_do_io_free(struct tape_device *device, struct tape_request *request)
{
int rc;
rc = tape_do_io(device, request);
tape_free_request(request);
return rc;
}
extern int tape_oper_handler(int irq, int status);
extern void tape_noper_handler(int irq, int status);
extern int tape_open(struct tape_device *);
extern int tape_release(struct tape_device *);
extern int tape_mtop(struct tape_device *, int, int);
extern void tape_state_set(struct tape_device *, enum tape_state);
extern int tape_generic_online(struct tape_device *, struct tape_discipline *);
extern int tape_generic_offline(struct tape_device *device);
/* Externals from tape_devmap.c */
extern int tape_generic_probe(struct ccw_device *);
extern void tape_generic_remove(struct ccw_device *);
extern struct tape_device *tape_get_device(int devindex);
extern struct tape_device *tape_get_device_reference(struct tape_device *);
extern struct tape_device *tape_put_device(struct tape_device *);
/* Externals from tape_char.c */
extern int tapechar_init(void);
extern void tapechar_exit(void);
extern int tapechar_setup_device(struct tape_device *);
extern void tapechar_cleanup_device(struct tape_device *);
/* Externals from tape_block.c */
#ifdef CONFIG_S390_TAPE_BLOCK
extern int tapeblock_init (void);
extern void tapeblock_exit(void);
extern int tapeblock_setup_device(struct tape_device *);
extern void tapeblock_cleanup_device(struct tape_device *);
#else
static inline int tapeblock_init (void) {return 0;}
static inline void tapeblock_exit (void) {;}
static inline int tapeblock_setup_device(struct tape_device *t) {return 0;}
static inline void tapeblock_cleanup_device (struct tape_device *t) {;}
#endif
/* tape initialisation functions */
#ifdef CONFIG_PROC_FS
extern void tape_proc_init (void);
extern void tape_proc_cleanup (void);
#else
static inline void tape_proc_init (void) {;}
static inline void tape_proc_cleanup (void) {;}
#endif
/* a function for dumping device sense info */
extern void tape_dump_sense(struct tape_device *, struct tape_request *,
struct irb *);
extern void tape_dump_sense_dbf(struct tape_device *, struct tape_request *,
struct irb *);
/* functions for handling the status of a device */
extern void tape_med_state_set(struct tape_device *, enum tape_medium_state);
/* The debug area */
extern debug_info_t *TAPE_DBF_AREA;
/* functions for building ccws */
static inline struct ccw1 *
tape_ccw_cc(struct ccw1 *ccw, __u8 cmd_code, __u16 memsize, void *cda)
{
ccw->cmd_code = cmd_code;
ccw->flags = CCW_FLAG_CC;
ccw->count = memsize;
ccw->cda = (__u32)(addr_t) cda;
return ccw + 1;
}
static inline struct ccw1 *
tape_ccw_end(struct ccw1 *ccw, __u8 cmd_code, __u16 memsize, void *cda)
{
ccw->cmd_code = cmd_code;
ccw->flags = 0;
ccw->count = memsize;
ccw->cda = (__u32)(addr_t) cda;
return ccw + 1;
}
static inline struct ccw1 *
tape_ccw_cmd(struct ccw1 *ccw, __u8 cmd_code)
{
ccw->cmd_code = cmd_code;
ccw->flags = 0;
ccw->count = 0;
ccw->cda = (__u32)(addr_t) &ccw->cmd_code;
return ccw + 1;
}
static inline struct ccw1 *
tape_ccw_repeat(struct ccw1 *ccw, __u8 cmd_code, int count)
{
while (count-- > 0) {
ccw->cmd_code = cmd_code;
ccw->flags = CCW_FLAG_CC;
ccw->count = 0;
ccw->cda = (__u32)(addr_t) &ccw->cmd_code;
ccw++;
}
return ccw;
}
static inline struct ccw1 *
tape_ccw_cc_idal(struct ccw1 *ccw, __u8 cmd_code, struct idal_buffer *idal)
{
ccw->cmd_code = cmd_code;
ccw->flags = CCW_FLAG_CC;
idal_buffer_set_cda(idal, ccw);
return ccw++;
}
static inline struct ccw1 *
tape_ccw_end_idal(struct ccw1 *ccw, __u8 cmd_code, struct idal_buffer *idal)
{
ccw->cmd_code = cmd_code;
ccw->flags = 0;
idal_buffer_set_cda(idal, ccw);
return ccw++;
}
/* Global vars */
extern const char *tape_state_verbose[];
extern const char *tape_op_verbose[];
#endif /* for ifdef tape.h */
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