Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 901 insertions, 0 deletions

diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
new file mode 100644
index 0000000000..4c2dc8150c
--- /dev/null
+++ b/include/scsi/scsi_host.h
@@ -0,0 +1,901 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#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>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+#include <linux/blk-mq.h>
+#include <scsi/scsi.h>
+
+struct block_device;
+struct completion;
+struct module;
+struct scsi_cmnd;
+struct scsi_device;
+struct scsi_target;
+struct Scsi_Host;
+struct scsi_transport_template;
+
+
+#define SG_ALL	SG_CHUNK_SIZE
+
+#define MODE_UNKNOWN 0x00
+#define MODE_INITIATOR 0x01
+#define MODE_TARGET 0x02
+
+/**
+ * enum scsi_timeout_action - How to handle a command that timed out.
+ * @SCSI_EH_DONE: The command has already been completed.
+ * @SCSI_EH_RESET_TIMER: Reset the timer and continue waiting for completion.
+ * @SCSI_EH_NOT_HANDLED: The command has not yet finished. Abort the command.
+ */
+enum scsi_timeout_action {
+	SCSI_EH_DONE,
+	SCSI_EH_RESET_TIMER,
+	SCSI_EH_NOT_HANDLED,
+};
+
+struct scsi_host_template {
+	/*
+	 * Put fields referenced in IO submission path together in
+	 * same cacheline
+	 */
+
+	/*
+	 * Additional per-command data allocated for the driver.
+	 */
+	unsigned int cmd_size;
+
+	/*
+	 * 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 driver has accepted the
+	 * command.  It must also push it to the HBA if the scsi_cmnd
+	 * flag SCMD_LAST is set, or if the driver does not implement
+	 * commit_rqs.  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_Host *, struct scsi_cmnd *);
+
+	/*
+	 * The commit_rqs function is used to trigger a hardware
+	 * doorbell after some requests have been queued with
+	 * queuecommand, when an error is encountered before sending
+	 * the request with SCMD_LAST set.
+	 *
+	 * STATUS: OPTIONAL
+	 */
+	void (*commit_rqs)(struct Scsi_Host *, u16);
+
+	struct module *module;
+	const char *name;
+
+	/*
+	 * 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, unsigned 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, unsigned int cmd,
+			    void __user *arg);
+#endif
+
+	int (*init_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
+	int (*exit_cmd_priv)(struct Scsi_Host *shost, struct scsi_cmnd *cmd);
+
+	/*
+	 * 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_abort_handler)(struct scsi_cmnd *);
+	int (* eh_device_reset_handler)(struct scsi_cmnd *);
+	int (* eh_target_reset_handler)(struct scsi_cmnd *);
+	int (* eh_bus_reset_handler)(struct scsi_cmnd *);
+	int (* eh_host_reset_handler)(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_change_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 *);
+
+	/*
+	 * If a host has the ability to discover targets on its own instead
+	 * of scanning the entire bus, it can fill in this function and
+	 * call scsi_scan_host().  This function will be called periodically
+	 * until it returns 1 with the scsi_host and the elapsed time of
+	 * the scan in jiffies.
+	 *
+	 * Status: OPTIONAL
+	 */
+	int (* scan_finished)(struct Scsi_Host *, unsigned long);
+
+	/*
+	 * If the host wants to be called before the scan starts, but
+	 * after the midlayer has set up ready for the scan, it can fill
+	 * in this function.
+	 *
+	 * Status: OPTIONAL
+	 */
+	void (* scan_start)(struct Scsi_Host *);
+
+	/*
+	 * 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.
+	 *
+	 * Status: OPTIONAL
+	 */
+	int (* change_queue_depth)(struct scsi_device *, int);
+
+	/*
+	 * This functions lets the driver expose the queue mapping
+	 * to the block layer.
+	 *
+	 * Status: OPTIONAL
+	 */
+	void (* map_queues)(struct Scsi_Host *shost);
+
+	/*
+	 * SCSI interface of blk_poll - poll for IO completions.
+	 * Only applicable if SCSI LLD exposes multiple h/w queues.
+	 *
+	 * Return value: Number of completed entries found.
+	 *
+	 * Status: OPTIONAL
+	 */
+	int (* mq_poll)(struct Scsi_Host *shost, unsigned int queue_num);
+
+	/*
+	 * Check if scatterlists need to be padded for DMA draining.
+	 *
+	 * Status: OPTIONAL
+	 */
+	bool (* dma_need_drain)(struct request *rq);
+
+	/*
+	 * 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 []);
+
+	/*
+	 * This function is called when one or more partitions on the
+	 * device reach beyond the end of the device.
+	 *
+	 * Status: OPTIONAL
+	 */
+	void (*unlock_native_capacity)(struct scsi_device *);
+
+	/*
+	 * 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 (*show_info)(struct seq_file *, struct Scsi_Host *);
+	int (*write_info)(struct Scsi_Host *, char *, int);
+
+	/*
+	 * This is an optional routine that allows the transport to become
+	 * involved when a scsi io timer fires. The return value tells the
+	 * timer routine how to finish the io timeout handling.
+	 *
+	 * Status: OPTIONAL
+	 */
+	enum scsi_timeout_action (*eh_timed_out)(struct scsi_cmnd *);
+	/*
+	 * Optional routine that allows the transport to decide if a cmd
+	 * is retryable. Return true if the transport is in a state the
+	 * cmd should be retried on.
+	 */
+	bool (*eh_should_retry_cmd)(struct scsi_cmnd *scmd);
+
+	/* This is an optional routine that allows transport to initiate
+	 * LLD adapter or firmware reset using sysfs attribute.
+	 *
+	 * Return values: 0 on success, -ve value on failure.
+	 *
+	 * Status: OPTIONAL
+	 */
+
+	int (*host_reset)(struct Scsi_Host *shost, int reset_type);
+#define SCSI_ADAPTER_RESET	1
+#define SCSI_FIRMWARE_RESET	2
+
+
+	/*
+	 * Name of proc directory
+	 */
+	const char *proc_name;
+
+	/*
+	 * 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 single hw queue in HBA 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;
+	unsigned short sg_prot_tablesize;
+
+	/*
+	 * Set this if the host adapter has limitations beside segment count.
+	 */
+	unsigned int max_sectors;
+
+	/*
+	 * Maximum size in bytes of a single segment.
+	 */
+	unsigned int max_segment_size;
+
+	/*
+	 * DMA scatter gather segment boundary limit. A segment crossing this
+	 * boundary will be split in two.
+	 */
+	unsigned long dma_boundary;
+
+	unsigned long virt_boundary_mask;
+
+	/*
+	 * 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;
+
+	/* If use block layer to manage tags, this is tag allocation policy */
+	int tag_alloc_policy;
+
+	/*
+	 * Track QUEUE_FULL events and reduce queue depth on demand.
+	 */
+	unsigned track_queue_depth:1;
+
+	/*
+	 * This specifies the mode that a LLD supports.
+	 */
+	unsigned supported_mode:2;
+
+	/*
+	 * 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;
+
+	/* True if the controller does not support WRITE SAME */
+	unsigned no_write_same:1;
+
+	/* True if the host uses host-wide tagspace */
+	unsigned host_tagset:1;
+
+	/* The queuecommand callback may block. See also BLK_MQ_F_BLOCKING. */
+	unsigned queuecommand_may_block: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 SCSI host sysfs attribute groups, NULL terminated.
+	 */
+	const struct attribute_group **shost_groups;
+
+	/*
+	 * Pointer to the SCSI device attribute groups for this host,
+	 * NULL terminated.
+	 */
+	const struct attribute_group **sdev_groups;
+
+	/*
+	 * Vendor Identifier associated with the host
+	 *
+	 * Note: When specifying vendor_id, be sure to read the
+	 *   Vendor Type and ID formatting requirements specified in
+	 *   scsi_netlink.h
+	 */
+	u64 vendor_id;
+
+	/* Delay for runtime autosuspend */
+	int rpm_autosuspend_delay;
+};
+
+/*
+ * Temporary #define for host lock push down. Can be removed when all
+ * drivers have been updated to take advantage of unlocked
+ * queuecommand.
+ *
+ */
+#define DEF_SCSI_QCMD(func_name) \
+	int func_name(struct Scsi_Host *shost, struct scsi_cmnd *cmd)	\
+	{								\
+		unsigned long irq_flags;				\
+		int rc;							\
+		spin_lock_irqsave(shost->host_lock, irq_flags);		\
+		rc = func_name##_lck(cmd);				\
+		spin_unlock_irqrestore(shost->host_lock, irq_flags);	\
+		return rc;						\
+	}
+
+
+/*
+ * shost state: If you alter this, you also need to alter scsi_sysfs.c
+ * (for the ascii descriptions) and the state model enforcer:
+ * scsi_host_set_state()
+ */
+enum scsi_host_state {
+	SHOST_CREATED = 1,
+	SHOST_RUNNING,
+	SHOST_CANCEL,
+	SHOST_DEL,
+	SHOST_RECOVERY,
+	SHOST_CANCEL_RECOVERY,
+	SHOST_DEL_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 being 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 list_head	starved_list;
+
+	spinlock_t		default_lock;
+	spinlock_t		*host_lock;
+
+	struct mutex		scan_mutex;/* serialize scanning activity */
+
+	struct list_head	eh_abort_list;
+	struct list_head	eh_cmd_q;
+	struct task_struct    * ehandler;  /* Error recovery thread. */
+	struct completion     * eh_action; /* Wait for specific actions on the
+					      host. */
+	wait_queue_head_t       host_wait;
+	const struct scsi_host_template *hostt;
+	struct scsi_transport_template *transportt;
+
+	struct kref		tagset_refcnt;
+	struct completion	tagset_freed;
+	/* Area to keep a shared tag map */
+	struct blk_mq_tag_set	tag_set;
+
+	atomic_t host_blocked;
+
+	unsigned int host_failed;	   /* commands that failed.
+					      protected by host_lock */
+	unsigned int host_eh_scheduled;    /* EH scheduled without command */
+    
+	unsigned int host_no;  /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
+
+	/* next two fields are used to bound the time spent in error handling */
+	int eh_deadline;
+	unsigned long last_reset;
+
+
+	/*
+	 * These three parameters can be used to allow for wide scsi,
+	 * and for host adapters that support multiple busses
+	 * The last two should be set to 1 more than the actual max id
+	 * or lun (e.g. 8 for SCSI parallel systems).
+	 */
+	unsigned int max_channel;
+	unsigned int max_id;
+	u64 max_lun;
+
+	/*
+	 * 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.
+	 * or 260 if the driver supports variable length cdbs.
+	 * For drivers that don't set this field, a value of 12 is
+	 * assumed.
+	 */
+	unsigned short max_cmd_len;
+
+	int this_id;
+	int can_queue;
+	short cmd_per_lun;
+	short unsigned int sg_tablesize;
+	short unsigned int sg_prot_tablesize;
+	unsigned int max_sectors;
+	unsigned int opt_sectors;
+	unsigned int max_segment_size;
+	unsigned long dma_boundary;
+	unsigned long virt_boundary_mask;
+	/*
+	 * In scsi-mq mode, the number of hardware queues supported by the LLD.
+	 *
+	 * Note: it is assumed that each hardware queue has a queue depth of
+	 * can_queue. In other words, the total queue depth per host
+	 * is nr_hw_queues * can_queue. However, for when host_tagset is set,
+	 * the total queue depth is can_queue.
+	 */
+	unsigned nr_hw_queues;
+	unsigned nr_maps;
+	unsigned active_mode:2;
+
+	/*
+	 * 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;
+
+	/* Task mgmt function in progress */
+	unsigned tmf_in_progress:1;
+
+	/* Asynchronous scan in progress */
+	unsigned async_scan:1;
+
+	/* Don't resume host in EH */
+	unsigned eh_noresume:1;
+
+	/* The controller does not support WRITE SAME */
+	unsigned no_write_same:1;
+
+	/* True if the host uses host-wide tagspace */
+	unsigned host_tagset:1;
+
+	/* The queuecommand callback may block. See also BLK_MQ_F_BLOCKING. */
+	unsigned queuecommand_may_block:1;
+
+	/* Host responded with short (<36 bytes) INQUIRY result */
+	unsigned short_inquiry:1;
+
+	/* The transport requires the LUN bits NOT to be stored in CDB[1] */
+	unsigned no_scsi2_lun_in_cdb:1;
+
+	/*
+	 * Optional work queue to be utilized by the transport
+	 */
+	char work_q_name[20];
+	struct workqueue_struct *work_q;
+
+	/*
+	 * Task management function work queue
+	 */
+	struct workqueue_struct *tmf_work_q;
+
+	/*
+	 * Value host_blocked counts down from
+	 */
+	unsigned int max_host_blocked;
+
+	/* Protection Information */
+	unsigned int prot_capabilities;
+	unsigned char prot_guard_type;
+
+	/* legacy crap */
+	unsigned long base;
+	unsigned long io_port;
+	unsigned char n_io_port;
+	unsigned char dma_channel;
+	unsigned int  irq;
+	
+
+	enum scsi_host_state shost_state;
+
+	/* ldm bits */
+	struct device		shost_gendev, shost_dev;
+
+	/*
+	 * Points to the transport data (if any) which is allocated
+	 * separately
+	 */
+	void *shost_data;
+
+	/*
+	 * Points to the physical bus device we'd use to do DMA
+	 * Needed just in case we have virtual hosts.
+	 */
+	struct device *dma_dev;
+
+	/*
+	 * 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[]  /* Used for storage of host specific stuff */
+		__attribute__ ((aligned (sizeof(unsigned long))));
+};
+
+#define		class_to_shost(d)	\
+	container_of(d, struct Scsi_Host, shost_dev)
+
+#define shost_printk(prefix, shost, fmt, a...)	\
+	dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)
+
+static inline void *shost_priv(struct Scsi_Host *shost)
+{
+	return (void *)shost->hostdata;
+}
+
+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);
+}
+
+static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
+{
+	return shost->shost_state == SHOST_RECOVERY ||
+		shost->shost_state == SHOST_CANCEL_RECOVERY ||
+		shost->shost_state == SHOST_DEL_RECOVERY ||
+		shost->tmf_in_progress;
+}
+
+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(const struct scsi_host_template *, int);
+extern int __must_check scsi_add_host_with_dma(struct Scsi_Host *,
+					       struct device *,
+					       struct device *);
+#if defined(CONFIG_SCSI_PROC_FS)
+struct proc_dir_entry *
+scsi_template_proc_dir(const struct scsi_host_template *sht);
+#else
+#define scsi_template_proc_dir(sht) NULL
+#endif
+extern void scsi_scan_host(struct Scsi_Host *);
+extern int scsi_rescan_device(struct scsi_device *sdev);
+extern void scsi_remove_host(struct Scsi_Host *);
+extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
+extern int scsi_host_busy(struct Scsi_Host *shost);
+extern void scsi_host_put(struct Scsi_Host *t);
+extern struct Scsi_Host *scsi_host_lookup(unsigned int hostnum);
+extern const char *scsi_host_state_name(enum scsi_host_state);
+extern void scsi_host_complete_all_commands(struct Scsi_Host *shost,
+					    enum scsi_host_status status);
+
+static inline int __must_check scsi_add_host(struct Scsi_Host *host,
+					     struct device *dev)
+{
+	return scsi_add_host_with_dma(host, dev, dev);
+}
+
+static inline struct device *scsi_get_device(struct Scsi_Host *shost)
+{
+        return shost->shost_gendev.parent;
+}
+
+/**
+ * scsi_host_scan_allowed - Is scanning of this host allowed
+ * @shost:	Pointer to Scsi_Host.
+ **/
+static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
+{
+	return shost->shost_state == SHOST_RUNNING ||
+	       shost->shost_state == SHOST_RECOVERY;
+}
+
+extern void scsi_unblock_requests(struct Scsi_Host *);
+extern void scsi_block_requests(struct Scsi_Host *);
+extern int scsi_host_block(struct Scsi_Host *shost);
+extern int scsi_host_unblock(struct Scsi_Host *shost, int new_state);
+
+void scsi_host_busy_iter(struct Scsi_Host *,
+			 bool (*fn)(struct scsi_cmnd *, void *), void *priv);
+
+struct class_container;
+
+/*
+ * DIF defines the exchange of protection information between
+ * initiator and SBC block device.
+ *
+ * DIX defines the exchange of protection information between OS and
+ * initiator.
+ */
+enum scsi_host_prot_capabilities {
+	SHOST_DIF_TYPE1_PROTECTION = 1 << 0, /* T10 DIF Type 1 */
+	SHOST_DIF_TYPE2_PROTECTION = 1 << 1, /* T10 DIF Type 2 */
+	SHOST_DIF_TYPE3_PROTECTION = 1 << 2, /* T10 DIF Type 3 */
+
+	SHOST_DIX_TYPE0_PROTECTION = 1 << 3, /* DIX between OS and HBA only */
+	SHOST_DIX_TYPE1_PROTECTION = 1 << 4, /* DIX with DIF Type 1 */
+	SHOST_DIX_TYPE2_PROTECTION = 1 << 5, /* DIX with DIF Type 2 */
+	SHOST_DIX_TYPE3_PROTECTION = 1 << 6, /* DIX with DIF Type 3 */
+};
+
+/*
+ * SCSI hosts which support the Data Integrity Extensions must
+ * indicate their capabilities by setting the prot_capabilities using
+ * this call.
+ */
+static inline void scsi_host_set_prot(struct Scsi_Host *shost, unsigned int mask)
+{
+	shost->prot_capabilities = mask;
+}
+
+static inline unsigned int scsi_host_get_prot(struct Scsi_Host *shost)
+{
+	return shost->prot_capabilities;
+}
+
+static inline int scsi_host_prot_dma(struct Scsi_Host *shost)
+{
+	return shost->prot_capabilities >= SHOST_DIX_TYPE0_PROTECTION;
+}
+
+static inline unsigned int scsi_host_dif_capable(struct Scsi_Host *shost, unsigned int target_type)
+{
+	static unsigned char cap[] = { 0,
+				       SHOST_DIF_TYPE1_PROTECTION,
+				       SHOST_DIF_TYPE2_PROTECTION,
+				       SHOST_DIF_TYPE3_PROTECTION };
+
+	if (target_type >= ARRAY_SIZE(cap))
+		return 0;
+
+	return shost->prot_capabilities & cap[target_type] ? target_type : 0;
+}
+
+static inline unsigned int scsi_host_dix_capable(struct Scsi_Host *shost, unsigned int target_type)
+{
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+	static unsigned char cap[] = { SHOST_DIX_TYPE0_PROTECTION,
+				       SHOST_DIX_TYPE1_PROTECTION,
+				       SHOST_DIX_TYPE2_PROTECTION,
+				       SHOST_DIX_TYPE3_PROTECTION };
+
+	if (target_type >= ARRAY_SIZE(cap))
+		return 0;
+
+	return shost->prot_capabilities & cap[target_type];
+#endif
+	return 0;
+}
+
+/*
+ * All DIX-capable initiators must support the T10-mandated CRC
+ * checksum.  Controllers can optionally implement the IP checksum
+ * scheme which has much lower impact on system performance.  Note
+ * that the main rationale for the checksum is to match integrity
+ * metadata with data.  Detecting bit errors are a job for ECC memory
+ * and buses.
+ */
+
+enum scsi_host_guard_type {
+	SHOST_DIX_GUARD_CRC = 1 << 0,
+	SHOST_DIX_GUARD_IP  = 1 << 1,
+};
+
+static inline void scsi_host_set_guard(struct Scsi_Host *shost, unsigned char type)
+{
+	shost->prot_guard_type = type;
+}
+
+static inline unsigned char scsi_host_get_guard(struct Scsi_Host *shost)
+{
+	return shost->prot_guard_type;
+}
+
+extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
+
+#endif /* _SCSI_SCSI_HOST_H */