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0c6924c262
Unbinding an I/O subchannel with a child-CCW device in disconnected state sometimes causes a kernel-panic. The race condition was seen mostly during testing, when setting all the CHPIDs of a device to offline and at the same time, the unbinding the I/O subchannel driver. The kernel-panic occurs because of double delete, the I/O subchannel driver calls device_del on the CCW device while another device_del invocation for the same device is in-flight. For instance, disabling all the CHPIDs will trigger the ccw_device_remove function, which will call a ccw_device_unregister(), which ends up calling the device_del() which is asynchronous via cdev's todo workqueue. And unbinding the I/O subchannel driver calls io_subchannel_remove() function which calls the ccw_device_unregister() and device_del(). This double delete can be prevented by serializing all CCW device registration/unregistration calls into the driver core. This patch introduces a mutex which will be used for this purpose. Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com> Reported-by: Boris Fiuczynski <fiuczy@linux.ibm.com> Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
238 lines
8.3 KiB
C
238 lines
8.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright IBM Corp. 2002, 2009
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*
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* Author(s): Arnd Bergmann <arndb@de.ibm.com>
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*
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* Interface for CCW device drivers
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*/
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#ifndef _S390_CCWDEV_H_
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#define _S390_CCWDEV_H_
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#include <linux/device.h>
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#include <linux/mod_devicetable.h>
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#include <asm/chsc.h>
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#include <asm/fcx.h>
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#include <asm/irq.h>
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#include <asm/schid.h>
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#include <linux/mutex.h>
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/* structs from asm/cio.h */
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struct irb;
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struct ccw1;
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struct ccw_dev_id;
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/* simplified initializers for struct ccw_device:
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* CCW_DEVICE and CCW_DEVICE_DEVTYPE initialize one
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* entry in your MODULE_DEVICE_TABLE and set the match_flag correctly */
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#define CCW_DEVICE(cu, cum) \
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.cu_type=(cu), .cu_model=(cum), \
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.match_flags=(CCW_DEVICE_ID_MATCH_CU_TYPE \
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| (cum ? CCW_DEVICE_ID_MATCH_CU_MODEL : 0))
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#define CCW_DEVICE_DEVTYPE(cu, cum, dev, devm) \
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.cu_type=(cu), .cu_model=(cum), .dev_type=(dev), .dev_model=(devm),\
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.match_flags=CCW_DEVICE_ID_MATCH_CU_TYPE \
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| ((cum) ? CCW_DEVICE_ID_MATCH_CU_MODEL : 0) \
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| CCW_DEVICE_ID_MATCH_DEVICE_TYPE \
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| ((devm) ? CCW_DEVICE_ID_MATCH_DEVICE_MODEL : 0)
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/* scan through an array of device ids and return the first
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* entry that matches the device.
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*
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* the array must end with an entry containing zero match_flags
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*/
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static inline const struct ccw_device_id *
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ccw_device_id_match(const struct ccw_device_id *array,
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const struct ccw_device_id *match)
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{
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const struct ccw_device_id *id = array;
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for (id = array; id->match_flags; id++) {
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if ((id->match_flags & CCW_DEVICE_ID_MATCH_CU_TYPE)
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&& (id->cu_type != match->cu_type))
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continue;
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if ((id->match_flags & CCW_DEVICE_ID_MATCH_CU_MODEL)
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&& (id->cu_model != match->cu_model))
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continue;
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if ((id->match_flags & CCW_DEVICE_ID_MATCH_DEVICE_TYPE)
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&& (id->dev_type != match->dev_type))
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continue;
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if ((id->match_flags & CCW_DEVICE_ID_MATCH_DEVICE_MODEL)
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&& (id->dev_model != match->dev_model))
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continue;
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return id;
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}
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return NULL;
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}
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/**
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* struct ccw_device - channel attached device
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* @ccwlock: pointer to device lock
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* @id: id of this device
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* @drv: ccw driver for this device
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* @dev: embedded device structure
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* @online: online status of device
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* @handler: interrupt handler
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*
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* @handler is a member of the device rather than the driver since a driver
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* can have different interrupt handlers for different ccw devices
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* (multi-subchannel drivers).
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*/
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struct ccw_device {
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spinlock_t *ccwlock;
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/* private: */
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struct ccw_device_private *private; /* cio private information */
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struct mutex reg_mutex;
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/* public: */
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struct ccw_device_id id;
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struct ccw_driver *drv;
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struct device dev;
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int online;
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void (*handler) (struct ccw_device *, unsigned long, struct irb *);
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};
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/*
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* Possible events used by the path_event notifier.
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*/
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#define PE_NONE 0x0
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#define PE_PATH_GONE 0x1 /* A path is no longer available. */
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#define PE_PATH_AVAILABLE 0x2 /* A path has become available and
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was successfully verified. */
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#define PE_PATHGROUP_ESTABLISHED 0x4 /* A pathgroup was reset and had
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to be established again. */
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#define PE_PATH_FCES_EVENT 0x8 /* The FCES Status of a path has
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* changed. */
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/*
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* Possible CIO actions triggered by the unit check handler.
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*/
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enum uc_todo {
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UC_TODO_RETRY,
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UC_TODO_RETRY_ON_NEW_PATH,
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UC_TODO_STOP
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};
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/**
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* struct ccw_driver - device driver for channel attached devices
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* @ids: ids supported by this driver
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* @probe: function called on probe
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* @remove: function called on remove
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* @set_online: called when setting device online
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* @set_offline: called when setting device offline
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* @notify: notify driver of device state changes
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* @path_event: notify driver of channel path events
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* @shutdown: called at device shutdown
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* @uc_handler: callback for unit check handler
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* @driver: embedded device driver structure
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* @int_class: interruption class to use for accounting interrupts
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*/
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struct ccw_driver {
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struct ccw_device_id *ids;
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int (*probe) (struct ccw_device *);
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void (*remove) (struct ccw_device *);
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int (*set_online) (struct ccw_device *);
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int (*set_offline) (struct ccw_device *);
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int (*notify) (struct ccw_device *, int);
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void (*path_event) (struct ccw_device *, int *);
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void (*shutdown) (struct ccw_device *);
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enum uc_todo (*uc_handler) (struct ccw_device *, struct irb *);
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struct device_driver driver;
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enum interruption_class int_class;
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};
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extern struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
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const char *bus_id);
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/* devices drivers call these during module load and unload.
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* When a driver is registered, its probe method is called
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* when new devices for its type pop up */
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extern int ccw_driver_register (struct ccw_driver *driver);
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extern void ccw_driver_unregister (struct ccw_driver *driver);
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extern int ccw_device_set_options_mask(struct ccw_device *, unsigned long);
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extern int ccw_device_set_options(struct ccw_device *, unsigned long);
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extern void ccw_device_clear_options(struct ccw_device *, unsigned long);
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int ccw_device_is_pathgroup(struct ccw_device *cdev);
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int ccw_device_is_multipath(struct ccw_device *cdev);
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/* Allow for i/o completion notification after primary interrupt status. */
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#define CCWDEV_EARLY_NOTIFICATION 0x0001
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/* Report all interrupt conditions. */
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#define CCWDEV_REPORT_ALL 0x0002
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/* Try to perform path grouping. */
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#define CCWDEV_DO_PATHGROUP 0x0004
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/* Allow forced onlining of boxed devices. */
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#define CCWDEV_ALLOW_FORCE 0x0008
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/* Try to use multipath mode. */
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#define CCWDEV_DO_MULTIPATH 0x0010
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extern int ccw_device_start(struct ccw_device *, struct ccw1 *,
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unsigned long, __u8, unsigned long);
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extern int ccw_device_start_timeout(struct ccw_device *, struct ccw1 *,
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unsigned long, __u8, unsigned long, int);
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extern int ccw_device_start_key(struct ccw_device *, struct ccw1 *,
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unsigned long, __u8, __u8, unsigned long);
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extern int ccw_device_start_timeout_key(struct ccw_device *, struct ccw1 *,
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unsigned long, __u8, __u8,
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unsigned long, int);
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extern int ccw_device_resume(struct ccw_device *);
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extern int ccw_device_halt(struct ccw_device *, unsigned long);
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extern int ccw_device_clear(struct ccw_device *, unsigned long);
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int ccw_device_tm_start_key(struct ccw_device *cdev, struct tcw *tcw,
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unsigned long intparm, u8 lpm, u8 key);
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int ccw_device_tm_start_key(struct ccw_device *, struct tcw *,
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unsigned long, u8, u8);
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int ccw_device_tm_start_timeout_key(struct ccw_device *, struct tcw *,
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unsigned long, u8, u8, int);
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int ccw_device_tm_start(struct ccw_device *, struct tcw *,
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unsigned long, u8);
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int ccw_device_tm_start_timeout(struct ccw_device *, struct tcw *,
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unsigned long, u8, int);
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int ccw_device_tm_intrg(struct ccw_device *cdev);
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int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask);
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extern int ccw_device_set_online(struct ccw_device *cdev);
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extern int ccw_device_set_offline(struct ccw_device *cdev);
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extern struct ciw *ccw_device_get_ciw(struct ccw_device *, __u32 cmd);
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extern __u8 ccw_device_get_path_mask(struct ccw_device *);
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extern void ccw_device_get_id(struct ccw_device *, struct ccw_dev_id *);
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#define get_ccwdev_lock(x) (x)->ccwlock
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#define to_ccwdev(n) container_of(n, struct ccw_device, dev)
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#define to_ccwdrv(n) container_of(n, struct ccw_driver, driver)
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extern struct ccw_device *ccw_device_create_console(struct ccw_driver *);
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extern void ccw_device_destroy_console(struct ccw_device *);
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extern int ccw_device_enable_console(struct ccw_device *);
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extern void ccw_device_wait_idle(struct ccw_device *);
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extern void *ccw_device_dma_zalloc(struct ccw_device *cdev, size_t size);
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extern void ccw_device_dma_free(struct ccw_device *cdev,
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void *cpu_addr, size_t size);
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int ccw_device_siosl(struct ccw_device *);
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extern void ccw_device_get_schid(struct ccw_device *, struct subchannel_id *);
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struct channel_path_desc_fmt0 *ccw_device_get_chp_desc(struct ccw_device *, int);
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u8 *ccw_device_get_util_str(struct ccw_device *cdev, int chp_idx);
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int ccw_device_pnso(struct ccw_device *cdev,
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struct chsc_pnso_area *pnso_area, u8 oc,
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struct chsc_pnso_resume_token resume_token, int cnc);
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int ccw_device_get_cssid(struct ccw_device *cdev, u8 *cssid);
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int ccw_device_get_iid(struct ccw_device *cdev, u8 *iid);
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int ccw_device_get_chpid(struct ccw_device *cdev, int chp_idx, u8 *chpid);
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int ccw_device_get_chid(struct ccw_device *cdev, int chp_idx, u16 *chid);
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#endif /* _S390_CCWDEV_H_ */
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