linux/drivers/s390/char/vmur.h
Michael Holzheu 8127a1f80a [S390] vmur: fix reference counting for vmur device structure
When a vmur device is removed due to a detach of the device, currently the
ur device structure is freed. Unfortunately it can happen, that there is
still a user of the device structure, when the character device is open
during the detach process. To fix this, reference counting for the vmur
structure is introduced.
In addition to that, the online, offline, probe and remove functions are
serialized now using a global mutex.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2007-08-22 13:51:48 +02:00

109 lines
2.9 KiB
C

/*
* Linux driver for System z and s390 unit record devices
* (z/VM virtual punch, reader, printer)
*
* Copyright IBM Corp. 2001, 2007
* Authors: Malcolm Beattie <beattiem@uk.ibm.com>
* Michael Holzheu <holzheu@de.ibm.com>
* Frank Munzert <munzert@de.ibm.com>
*/
#ifndef _VMUR_H_
#define _VMUR_H_
#define DEV_CLASS_UR_I 0x20 /* diag210 unit record input device class */
#define DEV_CLASS_UR_O 0x10 /* diag210 unit record output device class */
/*
* we only support z/VM's default unit record devices:
* both in SPOOL directory control statement and in CP DEFINE statement
* RDR defaults to 2540 reader
* PUN defaults to 2540 punch
* PRT defaults to 1403 printer
*/
#define READER_PUNCH_DEVTYPE 0x2540
#define PRINTER_DEVTYPE 0x1403
/* z/VM spool file control block SFBLOK */
struct file_control_block {
char reserved_1[8];
char user_owner[8];
char user_orig[8];
__s32 data_recs;
__s16 rec_len;
__s16 file_num;
__u8 file_stat;
__u8 dev_type;
char reserved_2[6];
char file_name[12];
char file_type[12];
char create_date[8];
char create_time[8];
char reserved_3[6];
__u8 file_class;
__u8 sfb_lok;
__u64 distr_code;
__u32 reserved_4;
__u8 current_starting_copy_number;
__u8 sfblock_cntrl_flags;
__u8 reserved_5;
__u8 more_status_flags;
char rest[200];
} __attribute__ ((packed));
#define FLG_SYSTEM_HOLD 0x04
#define FLG_CP_DUMP 0x10
#define FLG_USER_HOLD 0x20
#define FLG_IN_USE 0x80
/*
* A struct urdev is created for each ur device that is made available
* via the ccw_device driver model.
*/
struct urdev {
struct ccw_device *cdev; /* Backpointer to ccw device */
struct mutex io_mutex; /* Serialises device IO */
struct mutex open_mutex; /* Serialises access to device */
struct completion *io_done; /* do_ur_io waits; irq completes */
struct device *device;
struct cdev *char_device;
struct ccw_dev_id dev_id; /* device id */
size_t reclen; /* Record length for *write* CCWs */
int class; /* VM device class */
int io_request_rc; /* return code from I/O request */
atomic_t ref_count; /* reference counter */
};
/*
* A struct urfile is allocated at open() time for each device and
* freed on release().
*/
struct urfile {
struct urdev *urd;
unsigned int flags;
size_t dev_reclen;
__u16 file_reclen;
};
/*
* Device major/minor definitions.
*/
#define UR_MAJOR 0 /* get dynamic major */
/*
* We map minor numbers directly to device numbers (0-FFFF) for simplicity.
* This avoids having to allocate (and manage) slot numbers.
*/
#define NUM_MINORS 65536
/* Limiting each I/O to 511 records limits chan prog to 4KB (511 r/w + 1 NOP) */
#define MAX_RECS_PER_IO 511
#define WRITE_CCW_CMD 0x01
#define TRACE(x...) debug_sprintf_event(vmur_dbf, 1, x)
#define CCWDEV_CU_DI(cutype, di) \
CCW_DEVICE(cutype, 0x00), .driver_info = (di)
#define FILE_RECLEN_OFFSET 4064 /* reclen offset in spool data block */
#endif /* _VMUR_H_ */