include/linux/dynamic_debug.h


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#ifndef _DYNAMIC_DEBUG_H
#define _DYNAMIC_DEBUG_H

/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
 * bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
 * use independent hash functions, to reduce the chance of false positives.
 */
extern long long dynamic_debug_enabled;
extern long long dynamic_debug_enabled2;

/*
 * An instance of this structure is created in a special
 * ELF section at every dynamic debug callsite.  At runtime,
 * the special section is treated as an array of these.
 */
struct _ddebug {
	/*
	 * These fields are used to drive the user interface
	 * for selecting and displaying debug callsites.
	 */
	const char *modname;
	const char *function;
	const char *filename;
	const char *format;
	char primary_hash;
	char secondary_hash;
	unsigned int lineno:24;
	/*
 	 * The flags field controls the behaviour at the callsite.
 	 * The bits here are changed dynamically when the user
 	 * writes commands to <debugfs>/dynamic_debug/ddebug
	 */
#define _DPRINTK_FLAGS_PRINT   (1<<0)  /* printk() a message using the format */
#define _DPRINTK_FLAGS_DEFAULT 0
	unsigned int flags:8;
} __attribute__((aligned(8)));


int ddebug_add_module(struct _ddebug *tab, unsigned int n,
				const char *modname);

#if defined(CONFIG_DYNAMIC_DEBUG)
extern int ddebug_remove_module(char *mod_name);

#define __dynamic_dbg_enabled(dd)  ({	     \
	int __ret = 0;							     \
	if (unlikely((dynamic_debug_enabled & (1LL << DEBUG_HASH)) &&	     \
			(dynamic_debug_enabled2 & (1LL << DEBUG_HASH2))))   \
				if (unlikely(dd.flags))			     \
					__ret = 1;			     \
	__ret; })

#define dynamic_pr_debug(fmt, ...) do {					\
	static struct _ddebug descriptor				\
	__used								\
	__attribute__((section("__verbose"), aligned(8))) =		\
	{ KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH,	\
		DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT };	\
	if (__dynamic_dbg_enabled(descriptor))				\
		printk(KERN_DEBUG KBUILD_MODNAME ":" pr_fmt(fmt),	\
				##__VA_ARGS__);				\
	} while (0)


#define dynamic_dev_dbg(dev, fmt, ...) do {				\
	static struct _ddebug descriptor				\
	__used								\
	__attribute__((section("__verbose"), aligned(8))) =		\
	{ KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH,	\
		DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT };	\
	if (__dynamic_dbg_enabled(descriptor))				\
			dev_printk(KERN_DEBUG, dev,			\
					KBUILD_MODNAME ": " fmt,	\
					##__VA_ARGS__);			\
	} while (0)

#else

static inline int ddebug_remove_module(char *mod)
{
	return 0;
}

#define dynamic_pr_debug(fmt, ...)  do { } while (0)
#define dynamic_dev_dbg(dev, format, ...)  do { } while (0)
#endif

#endif
#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 <scsi/scsi.h>

struct request_queue;
struct block_device;
struct completion;
struct module;
struct scsi_cmnd;
struct scsi_device;
struct scsi_target;
struct Scsi_Host;
struct scsi_host_cmd_pool;
struct scsi_transport_template;
struct blk_queue_tags;


/*
 * 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.  The value we set here is the maximum
 *	 single element sglist.  To use chained sglists, the adapter
 *	 has to set a value beyond ALL (and correctly use the chain
 *	 handling API.
 * Anything else:  Indicates the maximum number of chains that can be
 *	 used in one scatter-gather request.
 */
#define SG_NONE 0
#define SG_ALL	SCSI_MAX_SG_SEGMENTS

#define MODE_UNKNOWN 0x00
#define MODE_INITIATOR 0x01
#define MODE_TARGET 0x02

#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 *));

	/*
	 * The transfer functions are used to queue a scsi command to
	 * the LLD. When the driver is finished processing the command
	 * the done callback is invoked.
	 *
	 * This is called to inform the LLD to transfer
	 * scsi_bufflen(cmd) bytes. scsi_sg_count(cmd) speciefies the
	 * number of scatterlist entried in the command and
	 * scsi_sglist(cmd) returns the scatterlist.
	 *
	 * return values: see queuecommand
	 *
	 * If the LLD accepts the cmd, it should set the result to an
	 * appropriate value when completed before calling the done function.
	 *
	 * STATUS: REQUIRED FOR TARGET DRIVERS
	 */
	/* TODO: rename */
	int (* transfer_response)(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_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_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 *);

	/*
	 * 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