fs: use kmem_cache_zalloc instead
[pv_ops_mirror.git] / include / scsi / scsi_host.h
blob0fd4746ee39d4437e788c37b9a7f59d9b65dc11a
1 #ifndef _SCSI_SCSI_HOST_H
2 #define _SCSI_SCSI_HOST_H
4 #include <linux/device.h>
5 #include <linux/list.h>
6 #include <linux/types.h>
7 #include <linux/workqueue.h>
8 #include <linux/mutex.h>
10 struct request_queue;
11 struct block_device;
12 struct completion;
13 struct module;
14 struct scsi_cmnd;
15 struct scsi_device;
16 struct scsi_target;
17 struct Scsi_Host;
18 struct scsi_host_cmd_pool;
19 struct scsi_transport_template;
20 struct blk_queue_tags;
24 * The various choices mean:
25 * NONE: Self evident. Host adapter is not capable of scatter-gather.
26 * ALL: Means that the host adapter module can do scatter-gather,
27 * and that there is no limit to the size of the table to which
28 * we scatter/gather data.
29 * Anything else: Indicates the maximum number of chains that can be
30 * used in one scatter-gather request.
32 #define SG_NONE 0
33 #define SG_ALL 0xff
35 #define MODE_UNKNOWN 0x00
36 #define MODE_INITIATOR 0x01
37 #define MODE_TARGET 0x02
39 #define DISABLE_CLUSTERING 0
40 #define ENABLE_CLUSTERING 1
42 #define DISABLE_SG_CHAINING 0
43 #define ENABLE_SG_CHAINING 1
45 enum scsi_eh_timer_return {
46 EH_NOT_HANDLED,
47 EH_HANDLED,
48 EH_RESET_TIMER,
52 struct scsi_host_template {
53 struct module *module;
54 const char *name;
57 * Used to initialize old-style drivers. For new-style drivers
58 * just perform all work in your module initialization function.
60 * Status: OBSOLETE
62 int (* detect)(struct scsi_host_template *);
65 * Used as unload callback for hosts with old-style drivers.
67 * Status: OBSOLETE
69 int (* release)(struct Scsi_Host *);
72 * The info function will return whatever useful information the
73 * developer sees fit. If not provided, then the name field will
74 * be used instead.
76 * Status: OPTIONAL
78 const char *(* info)(struct Scsi_Host *);
81 * Ioctl interface
83 * Status: OPTIONAL
85 int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
88 #ifdef CONFIG_COMPAT
89 /*
90 * Compat handler. Handle 32bit ABI.
91 * When unknown ioctl is passed return -ENOIOCTLCMD.
93 * Status: OPTIONAL
95 int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
96 #endif
99 * The queuecommand function is used to queue up a scsi
100 * command block to the LLDD. When the driver finished
101 * processing the command the done callback is invoked.
103 * If queuecommand returns 0, then the HBA has accepted the
104 * command. The done() function must be called on the command
105 * when the driver has finished with it. (you may call done on the
106 * command before queuecommand returns, but in this case you
107 * *must* return 0 from queuecommand).
109 * Queuecommand may also reject the command, in which case it may
110 * not touch the command and must not call done() for it.
112 * There are two possible rejection returns:
114 * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
115 * allow commands to other devices serviced by this host.
117 * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
118 * host temporarily.
120 * For compatibility, any other non-zero return is treated the
121 * same as SCSI_MLQUEUE_HOST_BUSY.
123 * NOTE: "temporarily" means either until the next command for#
124 * this device/host completes, or a period of time determined by
125 * I/O pressure in the system if there are no other outstanding
126 * commands.
128 * STATUS: REQUIRED
130 int (* queuecommand)(struct scsi_cmnd *,
131 void (*done)(struct scsi_cmnd *));
134 * The transfer functions are used to queue a scsi command to
135 * the LLD. When the driver is finished processing the command
136 * the done callback is invoked.
138 * This is called to inform the LLD to transfer
139 * cmd->request_bufflen bytes. The cmd->use_sg speciefies the
140 * number of scatterlist entried in the command and
141 * cmd->request_buffer contains the scatterlist.
143 * return values: see queuecommand
145 * If the LLD accepts the cmd, it should set the result to an
146 * appropriate value when completed before calling the done function.
148 * STATUS: REQUIRED FOR TARGET DRIVERS
150 /* TODO: rename */
151 int (* transfer_response)(struct scsi_cmnd *,
152 void (*done)(struct scsi_cmnd *));
155 * This is an error handling strategy routine. You don't need to
156 * define one of these if you don't want to - there is a default
157 * routine that is present that should work in most cases. For those
158 * driver authors that have the inclination and ability to write their
159 * own strategy routine, this is where it is specified. Note - the
160 * strategy routine is *ALWAYS* run in the context of the kernel eh
161 * thread. Thus you are guaranteed to *NOT* be in an interrupt
162 * handler when you execute this, and you are also guaranteed to
163 * *NOT* have any other commands being queued while you are in the
164 * strategy routine. When you return from this function, operations
165 * return to normal.
167 * See scsi_error.c scsi_unjam_host for additional comments about
168 * what this function should and should not be attempting to do.
170 * Status: REQUIRED (at least one of them)
172 int (* eh_abort_handler)(struct scsi_cmnd *);
173 int (* eh_device_reset_handler)(struct scsi_cmnd *);
174 int (* eh_bus_reset_handler)(struct scsi_cmnd *);
175 int (* eh_host_reset_handler)(struct scsi_cmnd *);
178 * Before the mid layer attempts to scan for a new device where none
179 * currently exists, it will call this entry in your driver. Should
180 * your driver need to allocate any structs or perform any other init
181 * items in order to send commands to a currently unused target/lun
182 * combo, then this is where you can perform those allocations. This
183 * is specifically so that drivers won't have to perform any kind of
184 * "is this a new device" checks in their queuecommand routine,
185 * thereby making the hot path a bit quicker.
187 * Return values: 0 on success, non-0 on failure
189 * Deallocation: If we didn't find any devices at this ID, you will
190 * get an immediate call to slave_destroy(). If we find something
191 * here then you will get a call to slave_configure(), then the
192 * device will be used for however long it is kept around, then when
193 * the device is removed from the system (or * possibly at reboot
194 * time), you will then get a call to slave_destroy(). This is
195 * assuming you implement slave_configure and slave_destroy.
196 * However, if you allocate memory and hang it off the device struct,
197 * then you must implement the slave_destroy() routine at a minimum
198 * in order to avoid leaking memory
199 * each time a device is tore down.
201 * Status: OPTIONAL
203 int (* slave_alloc)(struct scsi_device *);
206 * Once the device has responded to an INQUIRY and we know the
207 * device is online, we call into the low level driver with the
208 * struct scsi_device *. If the low level device driver implements
209 * this function, it *must* perform the task of setting the queue
210 * depth on the device. All other tasks are optional and depend
211 * on what the driver supports and various implementation details.
213 * Things currently recommended to be handled at this time include:
215 * 1. Setting the device queue depth. Proper setting of this is
216 * described in the comments for scsi_adjust_queue_depth.
217 * 2. Determining if the device supports the various synchronous
218 * negotiation protocols. The device struct will already have
219 * responded to INQUIRY and the results of the standard items
220 * will have been shoved into the various device flag bits, eg.
221 * device->sdtr will be true if the device supports SDTR messages.
222 * 3. Allocating command structs that the device will need.
223 * 4. Setting the default timeout on this device (if needed).
224 * 5. Anything else the low level driver might want to do on a device
225 * specific setup basis...
226 * 6. Return 0 on success, non-0 on error. The device will be marked
227 * as offline on error so that no access will occur. If you return
228 * non-0, your slave_destroy routine will never get called for this
229 * device, so don't leave any loose memory hanging around, clean
230 * up after yourself before returning non-0
232 * Status: OPTIONAL
234 int (* slave_configure)(struct scsi_device *);
237 * Immediately prior to deallocating the device and after all activity
238 * has ceased the mid layer calls this point so that the low level
239 * driver may completely detach itself from the scsi device and vice
240 * versa. The low level driver is responsible for freeing any memory
241 * it allocated in the slave_alloc or slave_configure calls.
243 * Status: OPTIONAL
245 void (* slave_destroy)(struct scsi_device *);
248 * Before the mid layer attempts to scan for a new device attached
249 * to a target where no target currently exists, it will call this
250 * entry in your driver. Should your driver need to allocate any
251 * structs or perform any other init items in order to send commands
252 * to a currently unused target, then this is where you can perform
253 * those allocations.
255 * Return values: 0 on success, non-0 on failure
257 * Status: OPTIONAL
259 int (* target_alloc)(struct scsi_target *);
262 * Immediately prior to deallocating the target structure, and
263 * after all activity to attached scsi devices has ceased, the
264 * midlayer calls this point so that the driver may deallocate
265 * and terminate any references to the target.
267 * Status: OPTIONAL
269 void (* target_destroy)(struct scsi_target *);
272 * If a host has the ability to discover targets on its own instead
273 * of scanning the entire bus, it can fill in this function and
274 * call scsi_scan_host(). This function will be called periodically
275 * until it returns 1 with the scsi_host and the elapsed time of
276 * the scan in jiffies.
278 * Status: OPTIONAL
280 int (* scan_finished)(struct Scsi_Host *, unsigned long);
283 * If the host wants to be called before the scan starts, but
284 * after the midlayer has set up ready for the scan, it can fill
285 * in this function.
287 void (* scan_start)(struct Scsi_Host *);
290 * fill in this function to allow the queue depth of this host
291 * to be changeable (on a per device basis). returns either
292 * the current queue depth setting (may be different from what
293 * was passed in) or an error. An error should only be
294 * returned if the requested depth is legal but the driver was
295 * unable to set it. If the requested depth is illegal, the
296 * driver should set and return the closest legal queue depth.
299 int (* change_queue_depth)(struct scsi_device *, int);
302 * fill in this function to allow the changing of tag types
303 * (this also allows the enabling/disabling of tag command
304 * queueing). An error should only be returned if something
305 * went wrong in the driver while trying to set the tag type.
306 * If the driver doesn't support the requested tag type, then
307 * it should set the closest type it does support without
308 * returning an error. Returns the actual tag type set.
310 int (* change_queue_type)(struct scsi_device *, int);
313 * This function determines the bios parameters for a given
314 * harddisk. These tend to be numbers that are made up by
315 * the host adapter. Parameters:
316 * size, device, list (heads, sectors, cylinders)
318 * Status: OPTIONAL */
319 int (* bios_param)(struct scsi_device *, struct block_device *,
320 sector_t, int []);
323 * Can be used to export driver statistics and other infos to the
324 * world outside the kernel ie. userspace and it also provides an
325 * interface to feed the driver with information.
327 * Status: OBSOLETE
329 int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int);
332 * This is an optional routine that allows the transport to become
333 * involved when a scsi io timer fires. The return value tells the
334 * timer routine how to finish the io timeout handling:
335 * EH_HANDLED: I fixed the error, please complete the command
336 * EH_RESET_TIMER: I need more time, reset the timer and
337 * begin counting again
338 * EH_NOT_HANDLED Begin normal error recovery
340 * Status: OPTIONAL
342 enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
345 * Name of proc directory
347 const char *proc_name;
350 * Used to store the procfs directory if a driver implements the
351 * proc_info method.
353 struct proc_dir_entry *proc_dir;
356 * This determines if we will use a non-interrupt driven
357 * or an interrupt driven scheme, It is set to the maximum number
358 * of simultaneous commands a given host adapter will accept.
360 int can_queue;
363 * In many instances, especially where disconnect / reconnect are
364 * supported, our host also has an ID on the SCSI bus. If this is
365 * the case, then it must be reserved. Please set this_id to -1 if
366 * your setup is in single initiator mode, and the host lacks an
367 * ID.
369 int this_id;
372 * This determines the degree to which the host adapter is capable
373 * of scatter-gather.
375 unsigned short sg_tablesize;
378 * If the host adapter has limitations beside segment count
380 unsigned short max_sectors;
383 * dma scatter gather segment boundary limit. a segment crossing this
384 * boundary will be split in two.
386 unsigned long dma_boundary;
389 * This specifies "machine infinity" for host templates which don't
390 * limit the transfer size. Note this limit represents an absolute
391 * maximum, and may be over the transfer limits allowed for
392 * individual devices (e.g. 256 for SCSI-1)
394 #define SCSI_DEFAULT_MAX_SECTORS 1024
397 * True if this host adapter can make good use of linked commands.
398 * This will allow more than one command to be queued to a given
399 * unit on a given host. Set this to the maximum number of command
400 * blocks to be provided for each device. Set this to 1 for one
401 * command block per lun, 2 for two, etc. Do not set this to 0.
402 * You should make sure that the host adapter will do the right thing
403 * before you try setting this above 1.
405 short cmd_per_lun;
408 * present contains counter indicating how many boards of this
409 * type were found when we did the scan.
411 unsigned char present;
414 * This specifies the mode that a LLD supports.
416 unsigned supported_mode:2;
419 * true if this host adapter uses unchecked DMA onto an ISA bus.
421 unsigned unchecked_isa_dma:1;
424 * true if this host adapter can make good use of clustering.
425 * I originally thought that if the tablesize was large that it
426 * was a waste of CPU cycles to prepare a cluster list, but
427 * it works out that the Buslogic is faster if you use a smaller
428 * number of segments (i.e. use clustering). I guess it is
429 * inefficient.
431 unsigned use_clustering:1;
434 * True for emulated SCSI host adapters (e.g. ATAPI)
436 unsigned emulated:1;
439 * True if the low-level driver performs its own reset-settle delays.
441 unsigned skip_settle_delay:1;
444 * ordered write support
446 unsigned ordered_tag:1;
449 * true if the low-level driver can support sg chaining. this
450 * will be removed eventually when all the drivers are
451 * converted to support sg chaining.
453 * Status: OBSOLETE
455 unsigned use_sg_chaining:1;
458 * Countdown for host blocking with no commands outstanding
460 unsigned int max_host_blocked;
463 * Default value for the blocking. If the queue is empty,
464 * host_blocked counts down in the request_fn until it restarts
465 * host operations as zero is reached.
467 * FIXME: This should probably be a value in the template
469 #define SCSI_DEFAULT_HOST_BLOCKED 7
472 * Pointer to the sysfs class properties for this host, NULL terminated.
474 struct class_device_attribute **shost_attrs;
477 * Pointer to the SCSI device properties for this host, NULL terminated.
479 struct device_attribute **sdev_attrs;
482 * List of hosts per template.
484 * This is only for use by scsi_module.c for legacy templates.
485 * For these access to it is synchronized implicitly by
486 * module_init/module_exit.
488 struct list_head legacy_hosts;
492 * shost state: If you alter this, you also need to alter scsi_sysfs.c
493 * (for the ascii descriptions) and the state model enforcer:
494 * scsi_host_set_state()
496 enum scsi_host_state {
497 SHOST_CREATED = 1,
498 SHOST_RUNNING,
499 SHOST_CANCEL,
500 SHOST_DEL,
501 SHOST_RECOVERY,
502 SHOST_CANCEL_RECOVERY,
503 SHOST_DEL_RECOVERY,
506 struct Scsi_Host {
508 * __devices is protected by the host_lock, but you should
509 * usually use scsi_device_lookup / shost_for_each_device
510 * to access it and don't care about locking yourself.
511 * In the rare case of beeing in irq context you can use
512 * their __ prefixed variants with the lock held. NEVER
513 * access this list directly from a driver.
515 struct list_head __devices;
516 struct list_head __targets;
518 struct scsi_host_cmd_pool *cmd_pool;
519 spinlock_t free_list_lock;
520 struct list_head free_list; /* backup store of cmd structs */
521 struct list_head starved_list;
523 spinlock_t default_lock;
524 spinlock_t *host_lock;
526 struct mutex scan_mutex;/* serialize scanning activity */
528 struct list_head eh_cmd_q;
529 struct task_struct * ehandler; /* Error recovery thread. */
530 struct completion * eh_action; /* Wait for specific actions on the
531 host. */
532 wait_queue_head_t host_wait;
533 struct scsi_host_template *hostt;
534 struct scsi_transport_template *transportt;
537 * area to keep a shared tag map (if needed, will be
538 * NULL if not)
540 struct blk_queue_tag *bqt;
543 * The following two fields are protected with host_lock;
544 * however, eh routines can safely access during eh processing
545 * without acquiring the lock.
547 unsigned int host_busy; /* commands actually active on low-level */
548 unsigned int host_failed; /* commands that failed. */
549 unsigned int host_eh_scheduled; /* EH scheduled without command */
551 unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
552 int resetting; /* if set, it means that last_reset is a valid value */
553 unsigned long last_reset;
556 * These three parameters can be used to allow for wide scsi,
557 * and for host adapters that support multiple busses
558 * The first two should be set to 1 more than the actual max id
559 * or lun (i.e. 8 for normal systems).
561 unsigned int max_id;
562 unsigned int max_lun;
563 unsigned int max_channel;
566 * This is a unique identifier that must be assigned so that we
567 * have some way of identifying each detected host adapter properly
568 * and uniquely. For hosts that do not support more than one card
569 * in the system at one time, this does not need to be set. It is
570 * initialized to 0 in scsi_register.
572 unsigned int unique_id;
575 * The maximum length of SCSI commands that this host can accept.
576 * Probably 12 for most host adapters, but could be 16 for others.
577 * For drivers that don't set this field, a value of 12 is
578 * assumed. I am leaving this as a number rather than a bit
579 * because you never know what subsequent SCSI standards might do
580 * (i.e. could there be a 20 byte or a 24-byte command a few years
581 * down the road?).
583 unsigned char max_cmd_len;
585 int this_id;
586 int can_queue;
587 short cmd_per_lun;
588 short unsigned int sg_tablesize;
589 short unsigned int max_sectors;
590 unsigned long dma_boundary;
592 * Used to assign serial numbers to the cmds.
593 * Protected by the host lock.
595 unsigned long cmd_serial_number;
597 unsigned active_mode:2;
598 unsigned unchecked_isa_dma:1;
599 unsigned use_clustering:1;
600 unsigned use_blk_tcq:1;
601 unsigned use_sg_chaining:1;
604 * Host has requested that no further requests come through for the
605 * time being.
607 unsigned host_self_blocked:1;
610 * Host uses correct SCSI ordering not PC ordering. The bit is
611 * set for the minority of drivers whose authors actually read
612 * the spec ;)
614 unsigned reverse_ordering:1;
617 * ordered write support
619 unsigned ordered_tag:1;
621 /* task mgmt function in progress */
622 unsigned tmf_in_progress:1;
624 /* Asynchronous scan in progress */
625 unsigned async_scan:1;
628 * Optional work queue to be utilized by the transport
630 char work_q_name[KOBJ_NAME_LEN];
631 struct workqueue_struct *work_q;
634 * Host has rejected a command because it was busy.
636 unsigned int host_blocked;
639 * Value host_blocked counts down from
641 unsigned int max_host_blocked;
644 * q used for scsi_tgt msgs, async events or any other requests that
645 * need to be processed in userspace
647 struct request_queue *uspace_req_q;
649 /* legacy crap */
650 unsigned long base;
651 unsigned long io_port;
652 unsigned char n_io_port;
653 unsigned char dma_channel;
654 unsigned int irq;
657 enum scsi_host_state shost_state;
659 /* ldm bits */
660 struct device shost_gendev;
661 struct class_device shost_classdev;
664 * List of hosts per template.
666 * This is only for use by scsi_module.c for legacy templates.
667 * For these access to it is synchronized implicitly by
668 * module_init/module_exit.
670 struct list_head sht_legacy_list;
673 * Points to the transport data (if any) which is allocated
674 * separately
676 void *shost_data;
679 * We should ensure that this is aligned, both for better performance
680 * and also because some compilers (m68k) don't automatically force
681 * alignment to a long boundary.
683 unsigned long hostdata[0] /* Used for storage of host specific stuff */
684 __attribute__ ((aligned (sizeof(unsigned long))));
687 #define class_to_shost(d) \
688 container_of(d, struct Scsi_Host, shost_classdev)
690 #define shost_printk(prefix, shost, fmt, a...) \
691 dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)
693 static inline void *shost_priv(struct Scsi_Host *shost)
695 return (void *)shost->hostdata;
698 int scsi_is_host_device(const struct device *);
700 static inline struct Scsi_Host *dev_to_shost(struct device *dev)
702 while (!scsi_is_host_device(dev)) {
703 if (!dev->parent)
704 return NULL;
705 dev = dev->parent;
707 return container_of(dev, struct Scsi_Host, shost_gendev);
710 static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
712 return shost->shost_state == SHOST_RECOVERY ||
713 shost->shost_state == SHOST_CANCEL_RECOVERY ||
714 shost->shost_state == SHOST_DEL_RECOVERY ||
715 shost->tmf_in_progress;
718 extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
719 extern void scsi_flush_work(struct Scsi_Host *);
721 extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
722 extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *);
723 extern void scsi_scan_host(struct Scsi_Host *);
724 extern void scsi_rescan_device(struct device *);
725 extern void scsi_remove_host(struct Scsi_Host *);
726 extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
727 extern void scsi_host_put(struct Scsi_Host *t);
728 extern struct Scsi_Host *scsi_host_lookup(unsigned short);
729 extern const char *scsi_host_state_name(enum scsi_host_state);
731 extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *);
733 static inline struct device *scsi_get_device(struct Scsi_Host *shost)
735 return shost->shost_gendev.parent;
739 * scsi_host_scan_allowed - Is scanning of this host allowed
740 * @shost: Pointer to Scsi_Host.
742 static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
744 return shost->shost_state == SHOST_RUNNING;
747 extern void scsi_unblock_requests(struct Scsi_Host *);
748 extern void scsi_block_requests(struct Scsi_Host *);
750 struct class_container;
752 extern struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
753 void (*) (struct request_queue *));
755 * These two functions are used to allocate and free a pseudo device
756 * which will connect to the host adapter itself rather than any
757 * physical device. You must deallocate when you are done with the
758 * thing. This physical pseudo-device isn't real and won't be available
759 * from any high-level drivers.
761 extern void scsi_free_host_dev(struct scsi_device *);
762 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
764 /* legacy interfaces */
765 extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
766 extern void scsi_unregister(struct Scsi_Host *);
767 extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
769 #endif /* _SCSI_SCSI_HOST_H */