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linux/include/scsi/scsi_host.h
James Bottomley a283bd37d0 [SCSI] Add target alloc/destroy callbacks to the host template 
This gives the HBA driver notice when a target is created and
destroyed to allow it to manage its own target based allocations
accordingly.

This is a much reduced verson of the original patch sent in by
James.Smart@Emulex.com

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-05-26 11:27:53 -04:00

674 lines
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#ifndef _SCSI_SCSI_HOST_H
#define _SCSI_SCSI_HOST_H
#include <linux/device.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/workqueue.h>
struct block_device;
struct module;
struct scsi_cmnd;
struct scsi_device;
struct scsi_target;
struct Scsi_Host;
struct scsi_host_cmd_pool;
struct scsi_transport_template;
/*
* The various choices mean:
* NONE: Self evident. Host adapter is not capable of scatter-gather.
* ALL: Means that the host adapter module can do scatter-gather,
* and that there is no limit to the size of the table to which
* we scatter/gather data.
* Anything else: Indicates the maximum number of chains that can be
* used in one scatter-gather request.
*/
#define SG_NONE 0
#define SG_ALL 0xff
#define DISABLE_CLUSTERING 0
#define ENABLE_CLUSTERING 1
enum scsi_eh_timer_return {
EH_NOT_HANDLED,
EH_HANDLED,
EH_RESET_TIMER,
};
struct scsi_host_template {
struct module *module;
const char *name;
/*
* Used to initialize old-style drivers. For new-style drivers
* just perform all work in your module initialization function.
*
* Status: OBSOLETE
*/
int (* detect)(struct scsi_host_template *);
/*
* Used as unload callback for hosts with old-style drivers.
*
* Status: OBSOLETE
*/
int (* release)(struct Scsi_Host *);
/*
* The info function will return whatever useful information the
* developer sees fit. If not provided, then the name field will
* be used instead.
*
* Status: OPTIONAL
*/
const char *(* info)(struct Scsi_Host *);
/*
* Ioctl interface
*
* Status: OPTIONAL
*/
int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
#ifdef CONFIG_COMPAT
/*
* Compat handler. Handle 32bit ABI.
* When unknown ioctl is passed return -ENOIOCTLCMD.
*
* Status: OPTIONAL
*/
int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
#endif
/*
* The queuecommand function is used to queue up a scsi
* command block to the LLDD. When the driver finished
* processing the command the done callback is invoked.
*
* If queuecommand returns 0, then the HBA has accepted the
* command. The done() function must be called on the command
* when the driver has finished with it. (you may call done on the
* command before queuecommand returns, but in this case you
* *must* return 0 from queuecommand).
*
* Queuecommand may also reject the command, in which case it may
* not touch the command and must not call done() for it.
*
* There are two possible rejection returns:
*
* SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
* allow commands to other devices serviced by this host.
*
* SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
* host temporarily.
*
* For compatibility, any other non-zero return is treated the
* same as SCSI_MLQUEUE_HOST_BUSY.
*
* NOTE: "temporarily" means either until the next command for#
* this device/host completes, or a period of time determined by
* I/O pressure in the system if there are no other outstanding
* commands.
*
* STATUS: REQUIRED
*/
int (* queuecommand)(struct scsi_cmnd *,
void (*done)(struct scsi_cmnd *));
/*
* This is an error handling strategy routine. You don't need to
* define one of these if you don't want to - there is a default
* routine that is present that should work in most cases. For those
* driver authors that have the inclination and ability to write their
* own strategy routine, this is where it is specified. Note - the
* strategy routine is *ALWAYS* run in the context of the kernel eh
* thread. Thus you are guaranteed to *NOT* be in an interrupt
* handler when you execute this, and you are also guaranteed to
* *NOT* have any other commands being queued while you are in the
* strategy routine. When you return from this function, operations
* return to normal.
*
* See scsi_error.c scsi_unjam_host for additional comments about
* what this function should and should not be attempting to do.
*
* Status: REQUIRED (at least one of them)
*/
int (* eh_strategy_handler)(struct Scsi_Host *);
int (* eh_abort_handler)(struct scsi_cmnd *);
int (* eh_device_reset_handler)(struct scsi_cmnd *);
int (* eh_bus_reset_handler)(struct scsi_cmnd *);
int (* eh_host_reset_handler)(struct scsi_cmnd *);
/*
* This is an optional routine to notify the host that the scsi
* timer just fired. The returns tell the timer routine what to
* do about this:
*
* EH_HANDLED: I fixed the error, please complete the command
* EH_RESET_TIMER: I need more time, reset the timer and
* begin counting again
* EH_NOT_HANDLED Begin normal error recovery
*
* Status: OPTIONAL
*/
enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
/*
* Before the mid layer attempts to scan for a new device where none
* currently exists, it will call this entry in your driver. Should
* your driver need to allocate any structs or perform any other init
* items in order to send commands to a currently unused target/lun
* combo, then this is where you can perform those allocations. This
* is specifically so that drivers won't have to perform any kind of
* "is this a new device" checks in their queuecommand routine,
* thereby making the hot path a bit quicker.
*
* Return values: 0 on success, non-0 on failure
*
* Deallocation: If we didn't find any devices at this ID, you will
* get an immediate call to slave_destroy(). If we find something
* here then you will get a call to slave_configure(), then the
* device will be used for however long it is kept around, then when
* the device is removed from the system (or * possibly at reboot
* time), you will then get a call to slave_destroy(). This is
* assuming you implement slave_configure and slave_destroy.
* However, if you allocate memory and hang it off the device struct,
* then you must implement the slave_destroy() routine at a minimum
* in order to avoid leaking memory
* each time a device is tore down.
*
* Status: OPTIONAL
*/
int (* slave_alloc)(struct scsi_device *);
/*
* Once the device has responded to an INQUIRY and we know the
* device is online, we call into the low level driver with the
* struct scsi_device *. If the low level device driver implements
* this function, it *must* perform the task of setting the queue
* depth on the device. All other tasks are optional and depend
* on what the driver supports and various implementation details.
*
* Things currently recommended to be handled at this time include:
*
* 1. Setting the device queue depth. Proper setting of this is
* described in the comments for scsi_adjust_queue_depth.
* 2. Determining if the device supports the various synchronous
* negotiation protocols. The device struct will already have
* responded to INQUIRY and the results of the standard items
* will have been shoved into the various device flag bits, eg.
* device->sdtr will be true if the device supports SDTR messages.
* 3. Allocating command structs that the device will need.
* 4. Setting the default timeout on this device (if needed).
* 5. Anything else the low level driver might want to do on a device
* specific setup basis...
* 6. Return 0 on success, non-0 on error. The device will be marked
* as offline on error so that no access will occur. If you return
* non-0, your slave_destroy routine will never get called for this
* device, so don't leave any loose memory hanging around, clean
* up after yourself before returning non-0
*
* Status: OPTIONAL
*/
int (* slave_configure)(struct scsi_device *);
/*
* Immediately prior to deallocating the device and after all activity
* has ceased the mid layer calls this point so that the low level
* driver may completely detach itself from the scsi device and vice
* versa. The low level driver is responsible for freeing any memory
* it allocated in the slave_alloc or slave_configure calls.
*
* Status: OPTIONAL
*/
void (* slave_destroy)(struct scsi_device *);
/*
* Before the mid layer attempts to scan for a new device attached
* to a target where no target currently exists, it will call this
* entry in your driver. Should your driver need to allocate any
* structs or perform any other init items in order to send commands
* to a currently unused target, then this is where you can perform
* those allocations.
*
* Return values: 0 on success, non-0 on failure
*
* Status: OPTIONAL
*/
int (* target_alloc)(struct scsi_target *);
/*
* Immediately prior to deallocating the target structure, and
* after all activity to attached scsi devices has ceased, the
* midlayer calls this point so that the driver may deallocate
* and terminate any references to the target.
*
* Status: OPTIONAL
*/
void (* target_destroy)(struct scsi_target *);
/*
* fill in this function to allow the queue depth of this host
* to be changeable (on a per device basis). returns either
* the current queue depth setting (may be different from what
* was passed in) or an error. An error should only be
* returned if the requested depth is legal but the driver was
* unable to set it. If the requested depth is illegal, the
* driver should set and return the closest legal queue depth.
*
*/
int (* change_queue_depth)(struct scsi_device *, int);
/*
* fill in this function to allow the changing of tag types
* (this also allows the enabling/disabling of tag command
* queueing). An error should only be returned if something
* went wrong in the driver while trying to set the tag type.
* If the driver doesn't support the requested tag type, then
* it should set the closest type it does support without
* returning an error. Returns the actual tag type set.
*/
int (* change_queue_type)(struct scsi_device *, int);
/*
* This function determines the bios parameters for a given
* harddisk. These tend to be numbers that are made up by
* the host adapter. Parameters:
* size, device, list (heads, sectors, cylinders)
*
* Status: OPTIONAL */
int (* bios_param)(struct scsi_device *, struct block_device *,
sector_t, int []);
/*
* Can be used to export driver statistics and other infos to the
* world outside the kernel ie. userspace and it also provides an
* interface to feed the driver with information.
*
* Status: OBSOLETE
*/
int (*proc_info)(struct Scsi_Host *, char *, char **, off_t, int, int);
/*
* Name of proc directory
*/
char *proc_name;
/*
* Used to store the procfs directory if a driver implements the
* proc_info method.
*/
struct proc_dir_entry *proc_dir;
/*
* This determines if we will use a non-interrupt driven
* or an interrupt driven scheme, It is set to the maximum number
* of simultaneous commands a given host adapter will accept.
*/
int can_queue;
/*
* In many instances, especially where disconnect / reconnect are
* supported, our host also has an ID on the SCSI bus. If this is
* the case, then it must be reserved. Please set this_id to -1 if
* your setup is in single initiator mode, and the host lacks an
* ID.
*/
int this_id;
/*
* This determines the degree to which the host adapter is capable
* of scatter-gather.
*/
unsigned short sg_tablesize;
/*
* If the host adapter has limitations beside segment count
*/
unsigned short max_sectors;
/*
* dma scatter gather segment boundary limit. a segment crossing this
* boundary will be split in two.
*/
unsigned long dma_boundary;
/*
* This specifies "machine infinity" for host templates which don't
* limit the transfer size. Note this limit represents an absolute
* maximum, and may be over the transfer limits allowed for
* individual devices (e.g. 256 for SCSI-1)
*/
#define SCSI_DEFAULT_MAX_SECTORS 1024
/*
* True if this host adapter can make good use of linked commands.
* This will allow more than one command to be queued to a given
* unit on a given host. Set this to the maximum number of command
* blocks to be provided for each device. Set this to 1 for one
* command block per lun, 2 for two, etc. Do not set this to 0.
* You should make sure that the host adapter will do the right thing
* before you try setting this above 1.
*/
short cmd_per_lun;
/*
* present contains counter indicating how many boards of this
* type were found when we did the scan.
*/
unsigned char present;
/*
* true if this host adapter uses unchecked DMA onto an ISA bus.
*/
unsigned unchecked_isa_dma:1;
/*
* true if this host adapter can make good use of clustering.
* I originally thought that if the tablesize was large that it
* was a waste of CPU cycles to prepare a cluster list, but
* it works out that the Buslogic is faster if you use a smaller
* number of segments (i.e. use clustering). I guess it is
* inefficient.
*/
unsigned use_clustering:1;
/*
* True for emulated SCSI host adapters (e.g. ATAPI)
*/
unsigned emulated:1;
/*
* True if the low-level driver performs its own reset-settle delays.
*/
unsigned skip_settle_delay:1;
/*
* ordered write support
*/
unsigned ordered_flush:1;
unsigned ordered_tag:1;
/*
* Countdown for host blocking with no commands outstanding
*/
unsigned int max_host_blocked;
/*
* Default value for the blocking. If the queue is empty,
* host_blocked counts down in the request_fn until it restarts
* host operations as zero is reached.
*
* FIXME: This should probably be a value in the template
*/
#define SCSI_DEFAULT_HOST_BLOCKED 7
/*
* Pointer to the sysfs class properties for this host, NULL terminated.
*/
struct class_device_attribute **shost_attrs;
/*
* Pointer to the SCSI device properties for this host, NULL terminated.
*/
struct device_attribute **sdev_attrs;
/*
* List of hosts per template.
*
* This is only for use by scsi_module.c for legacy templates.
* For these access to it is synchronized implicitly by
* module_init/module_exit.
*/
struct list_head legacy_hosts;
};
/*
* shost states
*/
enum {
SHOST_ADD,
SHOST_DEL,
SHOST_CANCEL,
SHOST_RECOVERY,
};
struct Scsi_Host {
/*
* __devices is protected by the host_lock, but you should
* usually use scsi_device_lookup / shost_for_each_device
* to access it and don't care about locking yourself.
* In the rare case of beeing in irq context you can use
* their __ prefixed variants with the lock held. NEVER
* access this list directly from a driver.
*/
struct list_head __devices;
struct list_head __targets;
struct scsi_host_cmd_pool *cmd_pool;
spinlock_t free_list_lock;
struct list_head free_list; /* backup store of cmd structs */
struct list_head starved_list;
spinlock_t default_lock;
spinlock_t *host_lock;
struct semaphore scan_mutex;/* serialize scanning activity */
struct list_head eh_cmd_q;
struct task_struct * ehandler; /* Error recovery thread. */
struct semaphore * eh_wait; /* The error recovery thread waits
on this. */
struct completion * eh_notify; /* wait for eh to begin or end */
struct semaphore * eh_action; /* Wait for specific actions on the
host. */
unsigned int eh_active:1; /* Indicates the eh thread is awake and active if
this is true. */
unsigned int eh_kill:1; /* set when killing the eh thread */
wait_queue_head_t host_wait;
struct scsi_host_template *hostt;
struct scsi_transport_template *transportt;
/*
* The following two fields are protected with host_lock;
* however, eh routines can safely access during eh processing
* without acquiring the lock.
*/
unsigned int host_busy; /* commands actually active on low-level */
unsigned int host_failed; /* commands that failed. */
unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
int resetting; /* if set, it means that last_reset is a valid value */
unsigned long last_reset;
/*
* These three parameters can be used to allow for wide scsi,
* and for host adapters that support multiple busses
* The first two should be set to 1 more than the actual max id
* or lun (i.e. 8 for normal systems).
*/
unsigned int max_id;
unsigned int max_lun;
unsigned int max_channel;
/*
* This is a unique identifier that must be assigned so that we
* have some way of identifying each detected host adapter properly
* and uniquely. For hosts that do not support more than one card
* in the system at one time, this does not need to be set. It is
* initialized to 0 in scsi_register.
*/
unsigned int unique_id;
/*
* The maximum length of SCSI commands that this host can accept.
* Probably 12 for most host adapters, but could be 16 for others.
* For drivers that don't set this field, a value of 12 is
* assumed. I am leaving this as a number rather than a bit
* because you never know what subsequent SCSI standards might do
* (i.e. could there be a 20 byte or a 24-byte command a few years
* down the road?).
*/
unsigned char max_cmd_len;
int this_id;
int can_queue;
short cmd_per_lun;
short unsigned int sg_tablesize;
short unsigned int max_sectors;
unsigned long dma_boundary;
/*
* Used to assign serial numbers to the cmds.
* Protected by the host lock.
*/
unsigned long cmd_serial_number, cmd_pid;
unsigned unchecked_isa_dma:1;
unsigned use_clustering:1;
unsigned use_blk_tcq:1;
/*
* Host has requested that no further requests come through for the
* time being.
*/
unsigned host_self_blocked:1;
/*
* Host uses correct SCSI ordering not PC ordering. The bit is
* set for the minority of drivers whose authors actually read
* the spec ;)
*/
unsigned reverse_ordering:1;
/*
* ordered write support
*/
unsigned ordered_flush:1;
unsigned ordered_tag:1;
/*
* Optional work queue to be utilized by the transport
*/
char work_q_name[KOBJ_NAME_LEN];
struct workqueue_struct *work_q;
/*
* Host has rejected a command because it was busy.
*/
unsigned int host_blocked;
/*
* Value host_blocked counts down from
*/
unsigned int max_host_blocked;
/* legacy crap */
unsigned long base;
unsigned long io_port;
unsigned char n_io_port;
unsigned char dma_channel;
unsigned int irq;
unsigned long shost_state;
/* ldm bits */
struct device shost_gendev;
struct class_device shost_classdev;
/*
* List of hosts per template.
*
* This is only for use by scsi_module.c for legacy templates.
* For these access to it is synchronized implicitly by
* module_init/module_exit.
*/
struct list_head sht_legacy_list;
/*
* Points to the transport data (if any) which is allocated
* separately
*/
void *shost_data;
/*
* We should ensure that this is aligned, both for better performance
* and also because some compilers (m68k) don't automatically force
* alignment to a long boundary.
*/
unsigned long hostdata[0] /* Used for storage of host specific stuff */
__attribute__ ((aligned (sizeof(unsigned long))));
};
#define class_to_shost(d) \
container_of(d, struct Scsi_Host, shost_classdev)
int scsi_is_host_device(const struct device *);
static inline struct Scsi_Host *dev_to_shost(struct device *dev)
{
while (!scsi_is_host_device(dev)) {
if (!dev->parent)
return NULL;
dev = dev->parent;
}
return container_of(dev, struct Scsi_Host, shost_gendev);
}
extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
extern void scsi_flush_work(struct Scsi_Host *);
extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
extern int __must_check scsi_add_host(struct Scsi_Host *, struct device *);
extern void scsi_scan_host(struct Scsi_Host *);
extern void scsi_scan_single_target(struct Scsi_Host *, unsigned int,
unsigned int);
extern void scsi_rescan_device(struct device *);
extern void scsi_remove_host(struct Scsi_Host *);
extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
extern void scsi_host_put(struct Scsi_Host *t);
extern struct Scsi_Host *scsi_host_lookup(unsigned short);
extern u64 scsi_calculate_bounce_limit(struct Scsi_Host *);
static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock)
{
shost->host_lock = lock;
}
static inline void scsi_set_device(struct Scsi_Host *shost,
struct device *dev)
{
shost->shost_gendev.parent = dev;
}
static inline struct device *scsi_get_device(struct Scsi_Host *shost)
{
return shost->shost_gendev.parent;
}
extern void scsi_unblock_requests(struct Scsi_Host *);
extern void scsi_block_requests(struct Scsi_Host *);
struct class_container;
/*
* These two functions are used to allocate and free a pseudo device
* which will connect to the host adapter itself rather than any
* physical device. You must deallocate when you are done with the
* thing. This physical pseudo-device isn't real and won't be available
* from any high-level drivers.
*/
extern void scsi_free_host_dev(struct scsi_device *);
extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
/* legacy interfaces */
extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
extern void scsi_unregister(struct Scsi_Host *);
#endif /* _SCSI_SCSI_HOST_H */
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