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linux_dsm_epyc7002/drivers/s390/char/tape.h
Martin Schwidefsky 4657fb8a98 [S390] tape: fix race with stack local wait_queue_head_t. 
A wait_event call with a stack local wait_queue_head_t structure that is
used to do the wake up for the wait_event is inherently racy. After the
wait_event finished the wake_up call might not have completed yet.
Replace the stack local wait_queue_head_t in tape_do_io and
tape_do_io_interruptible with a per device wait queue.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-05-30 10:03:36 +02:00

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/*
* drivers/s390/char/tape.h
* tape device driver for 3480/3490E/3590 tapes.
*
* S390 and zSeries version
* Copyright IBM Corp. 2001,2006
* 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/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_CRYPT_ON, /* Enable encrpytion */
TO_CRYPT_OFF, /* Disable encrpytion */
TO_KEKL_SET, /* Set KEK label */
TO_KEKL_QUERY, /* Query KEK label */
TO_RDC, /* Read device characteristics */
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_REQUEST_LONG_BUSY, /* request has to be restarted after long busy */
};
/* 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 */
#define TAPE_IO_LONG_BUSY 4 /* delay 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
{
struct tape_device * device;
/* Block device request queue. */
struct request_queue * 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;
/* Request wait queue. */
wait_queue_head_t wait_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 delayed_work tape_dnr;
/* Timer for long busy */
struct timer_list lb_timeout;
};
/* 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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