scsi.c

讲述linux的初始化过程

}

/*
 * Function:    scsi_finish_command
 *
 * Purpose:     Pass command off to upper layer for finishing of I/O
 *              request, waking processes that are waiting on results,
 *              etc.
 */
void scsi_finish_command(Scsi_Cmnd * SCpnt)
{
	struct Scsi_Host *host;
	Scsi_Device *device;
	Scsi_Request * SRpnt;
	unsigned long flags;

	ASSERT_LOCK(&io_request_lock, 0);

	host = SCpnt->host;
	device = SCpnt->device;

        /*
         * We need to protect the decrement, as otherwise a race condition
         * would exist.  Fiddling with SCpnt isn't a problem as the
         * design only allows a single SCpnt to be active in only
         * one execution context, but the device and host structures are
         * shared.
         */
	spin_lock_irqsave(&io_request_lock, flags);
	host->host_busy--;	/* Indicate that we are free */
	device->device_busy--;	/* Decrement device usage counter. */
	spin_unlock_irqrestore(&io_request_lock, flags);

        /*
         * Clear the flags which say that the device/host is no longer
         * capable of accepting new commands.  These are set in scsi_queue.c
         * for both the queue full condition on a device, and for a
         * host full condition on the host.
         */
        host->host_blocked = FALSE;
        device->device_blocked = FALSE;

	/*
	 * If we have valid sense information, then some kind of recovery
	 * must have taken place.  Make a note of this.
	 */
	if (scsi_sense_valid(SCpnt)) {
		SCpnt->result |= (DRIVER_SENSE << 24);
	}
	SCSI_LOG_MLCOMPLETE(3, printk("Notifying upper driver of completion for device %d %x\n",
				      SCpnt->device->id, SCpnt->result));

	SCpnt->owner = SCSI_OWNER_HIGHLEVEL;
	SCpnt->state = SCSI_STATE_FINISHED;

	/* We can get here with use_sg=0, causing a panic in the upper level (DB) */
	SCpnt->use_sg = SCpnt->old_use_sg;

       /*
	* If there is an associated request structure, copy the data over before we call the
	* completion function.
	*/
	SRpnt = SCpnt->sc_request;
	if( SRpnt != NULL ) {
	       SRpnt->sr_result = SRpnt->sr_command->result;
	       if( SRpnt->sr_result != 0 ) {
		       memcpy(SRpnt->sr_sense_buffer,
			      SRpnt->sr_command->sense_buffer,
			      sizeof(SRpnt->sr_sense_buffer));
	       }
	}

	SCpnt->done(SCpnt);
}

static int scsi_register_host(Scsi_Host_Template *);
static void scsi_unregister_host(Scsi_Host_Template *);

/*
 * Function:    scsi_release_commandblocks()
 *
 * Purpose:     Release command blocks associated with a device.
 *
 * Arguments:   SDpnt   - device
 *
 * Returns:     Nothing
 *
 * Lock status: No locking assumed or required.
 *
 * Notes:
 */
void scsi_release_commandblocks(Scsi_Device * SDpnt)
{
	Scsi_Cmnd *SCpnt, *SCnext;
	unsigned long flags;

 	spin_lock_irqsave(&device_request_lock, flags);
	for (SCpnt = SDpnt->device_queue; SCpnt; SCpnt = SCnext) {
		SDpnt->device_queue = SCnext = SCpnt->next;
		kfree((char *) SCpnt);
	}
	SDpnt->has_cmdblocks = 0;
	SDpnt->queue_depth = 0;
	spin_unlock_irqrestore(&device_request_lock, flags);
}

/*
 * Function:    scsi_build_commandblocks()
 *
 * Purpose:     Allocate command blocks associated with a device.
 *
 * Arguments:   SDpnt   - device
 *
 * Returns:     Nothing
 *
 * Lock status: No locking assumed or required.
 *
 * Notes:
 */
void scsi_build_commandblocks(Scsi_Device * SDpnt)
{
	unsigned long flags;
	struct Scsi_Host *host = SDpnt->host;
	int j;
	Scsi_Cmnd *SCpnt;

	spin_lock_irqsave(&device_request_lock, flags);

	if (SDpnt->queue_depth == 0)
	{
		SDpnt->queue_depth = host->cmd_per_lun;
		if (SDpnt->queue_depth == 0)
			SDpnt->queue_depth = 1; /* live to fight another day */
	}
	SDpnt->device_queue = NULL;

	for (j = 0; j < SDpnt->queue_depth; j++) {
		SCpnt = (Scsi_Cmnd *)
		    kmalloc(sizeof(Scsi_Cmnd),
				     GFP_ATOMIC |
				(host->unchecked_isa_dma ? GFP_DMA : 0));
		if (NULL == SCpnt)
			break;	/* If not, the next line will oops ... */
		memset(SCpnt, 0, sizeof(Scsi_Cmnd));
		SCpnt->host = host;
		SCpnt->device = SDpnt;
		SCpnt->target = SDpnt->id;
		SCpnt->lun = SDpnt->lun;
		SCpnt->channel = SDpnt->channel;
		SCpnt->request.rq_status = RQ_INACTIVE;
		SCpnt->use_sg = 0;
		SCpnt->old_use_sg = 0;
		SCpnt->old_cmd_len = 0;
		SCpnt->underflow = 0;
		SCpnt->old_underflow = 0;
		SCpnt->transfersize = 0;
		SCpnt->resid = 0;
		SCpnt->serial_number = 0;
		SCpnt->serial_number_at_timeout = 0;
		SCpnt->host_scribble = NULL;
		SCpnt->next = SDpnt->device_queue;
		SDpnt->device_queue = SCpnt;
		SCpnt->state = SCSI_STATE_UNUSED;
		SCpnt->owner = SCSI_OWNER_NOBODY;
	}
	if (j < SDpnt->queue_depth) {	/* low on space (D.Gilbert 990424) */
		printk(KERN_WARNING "scsi_build_commandblocks: want=%d, space for=%d blocks\n",
		       SDpnt->queue_depth, j);
		SDpnt->queue_depth = j;
		SDpnt->has_cmdblocks = (0 != j);
	} else {
		SDpnt->has_cmdblocks = 1;
	}
	spin_unlock_irqrestore(&device_request_lock, flags);
}

static int proc_scsi_gen_write(struct file * file, const char * buf,
                              unsigned long length, void *data);

void __init scsi_host_no_insert(char *str, int n)
{
    Scsi_Host_Name *shn, *shn2;
    int len;
    
    len = strlen(str);
    if (len && (shn = (Scsi_Host_Name *) kmalloc(sizeof(Scsi_Host_Name), GFP_ATOMIC))) {
	if ((shn->name = kmalloc(len+1, GFP_ATOMIC))) {
	    strncpy(shn->name, str, len);
	    shn->name[len] = 0;
	    shn->host_no = n;
	    shn->host_registered = 0;
	    shn->loaded_as_module = 1; /* numbers shouldn't be freed in any case */
	    shn->next = NULL;
	    if (scsi_host_no_list) {
		for (shn2 = scsi_host_no_list;shn2->next;shn2 = shn2->next)
		    ;
		shn2->next = shn;
	    }
	    else
		scsi_host_no_list = shn;
	    max_scsi_hosts = n+1;
	}
	else
	    kfree((char *) shn);
    }
}

#ifdef CONFIG_PROC_FS
static int scsi_proc_info(char *buffer, char **start, off_t offset, int length)
{
	Scsi_Device *scd;
	struct Scsi_Host *HBA_ptr;
	int size, len = 0;
	off_t begin = 0;
	off_t pos = 0;

	/*
	 * First, see if there are any attached devices or not.
	 */
	for (HBA_ptr = scsi_hostlist; HBA_ptr; HBA_ptr = HBA_ptr->next) {
		if (HBA_ptr->host_queue != NULL) {
			break;
		}
	}
	size = sprintf(buffer + len, "Attached devices: %s\n", (HBA_ptr) ? "" : "none");
	len += size;
	pos = begin + len;
	for (HBA_ptr = scsi_hostlist; HBA_ptr; HBA_ptr = HBA_ptr->next) {
#if 0
		size += sprintf(buffer + len, "scsi%2d: %s\n", (int) HBA_ptr->host_no,
				HBA_ptr->hostt->procname);
		len += size;
		pos = begin + len;
#endif
		for (scd = HBA_ptr->host_queue; scd; scd = scd->next) {
			proc_print_scsidevice(scd, buffer, &size, len);
			len += size;
			pos = begin + len;

			if (pos < offset) {
				len = 0;
				begin = pos;
			}
			if (pos > offset + length)
				goto stop_output;
		}
	}

stop_output:
	*start = buffer + (offset - begin);	/* Start of wanted data */
	len -= (offset - begin);	/* Start slop */
	if (len > length)
		len = length;	/* Ending slop */
	return (len);
}

static int proc_scsi_gen_write(struct file * file, const char * buf,
                              unsigned long length, void *data)
{
	struct Scsi_Device_Template *SDTpnt;
	Scsi_Device *scd;
	struct Scsi_Host *HBA_ptr;
	char *p;
	int host, channel, id, lun;
	char * buffer;
	int err;

	if (!buf || length>PAGE_SIZE)
		return -EINVAL;

	if (!(buffer = (char *) __get_free_page(GFP_KERNEL)))
		return -ENOMEM;
	copy_from_user(buffer, buf, length);

	err = -EINVAL;
	if (length < 11 || strncmp("scsi", buffer, 4))
		goto out;

	/*
	 * Usage: echo "scsi dump #N" > /proc/scsi/scsi
	 * to dump status of all scsi commands.  The number is used to specify the level
	 * of detail in the dump.
	 */
	if (!strncmp("dump", buffer + 5, 4)) {
		unsigned int level;

		p = buffer + 10;

		if (*p == '\0')
			goto out;

		level = simple_strtoul(p, NULL, 0);
		scsi_dump_status(level);
	}
	/*
	 * Usage: echo "scsi log token #N" > /proc/scsi/scsi
	 * where token is one of [error,scan,mlqueue,mlcomplete,llqueue,
	 * llcomplete,hlqueue,hlcomplete]
	 */
#ifdef CONFIG_SCSI_LOGGING		/* { */

	if (!strncmp("log", buffer + 5, 3)) {
		char *token;
		unsigned int level;

		p = buffer + 9;
		token = p;
		while (*p != ' ' && *p != '\t' && *p != '\0') {
			p++;
		}

		if (*p == '\0') {
			if (strncmp(token, "all", 3) == 0) {
				/*
				 * Turn on absolutely everything.
				 */
				scsi_logging_level = ~0;
			} else if (strncmp(token, "none", 4) == 0) {
				/*
				 * Turn off absolutely everything.
				 */
				scsi_logging_level = 0;
			} else {
				goto out;
			}
		} else {
			*p++ = '\0';

			level = simple_strtoul(p, NULL, 0);

			/*
			 * Now figure out what to do with it.
			 */
			if (strcmp(token, "error") == 0) {
				SCSI_SET_ERROR_RECOVERY_LOGGING(level);
			} else if (strcmp(token, "timeout") == 0) {
				SCSI_SET_TIMEOUT_LOGGING(level);
			} else if (strcmp(token, "scan") == 0) {
				SCSI_SET_SCAN_BUS_LOGGING(level);
			} else if (strcmp(token, "mlqueue") == 0) {
				SCSI_SET_MLQUEUE_LOGGING(level);
			} else if (strcmp(token, "mlcomplete") == 0) {
				SCSI_SET_MLCOMPLETE_LOGGING(level);
			} else if (strcmp(token, "llqueue") == 0) {
				SCSI_SET_LLQUEUE_LOGGING(level);
			} else if (strcmp(token, "llcomplete") == 0) {
				SCSI_SET_LLCOMPLETE_LOGGING(level);
			} else if (strcmp(token, "hlqueue") == 0) {
				SCSI_SET_HLQUEUE_LOGGING(level);
			} else if (strcmp(token, "hlcomplete") == 0) {
				SCSI_SET_HLCOMPLETE_LOGGING(level);
			} else if (strcmp(token, "ioctl") == 0) {
				SCSI_SET_IOCTL_LOGGING(level);
			} else {
				goto out;
			}
		}

		printk(KERN_INFO "scsi logging level set to 0x%8.8x\n", scsi_logging_level);
	}
#endif	/* CONFIG_SCSI_LOGGING */ /* } */

	/*
	 * Usage: echo "scsi add-single-device 0 1 2 3" >/proc/scsi/scsi
	 * with  "0 1 2 3" replaced by your "Host Channel Id Lun".
	 * Consider this feature BETA.
	 *     CAUTION: This is not for hotplugging your peripherals. As
	 *     SCSI was not designed for this you could damage your
	 *     hardware !
	 * However perhaps it is legal to switch on an
	 * already connected device. It is perhaps not
	 * guaranteed this device doesn't corrupt an ongoing data transfer.
	 */
	if (!strncmp("add-single-device", buffer + 5, 17)) {
		p = buffer + 23;

		host = simple_strtoul(p, &p, 0);
		channel = simple_strtoul(p + 1, &p, 0);
		id = simple_strtoul(p + 1, &p, 0);
		lun = simple_strtoul(p + 1, &p, 0);

		printk(KERN_INFO "scsi singledevice %d %d %d %d\n", host, channel,
		       id, lun);

		for (HBA_ptr = scsi_hostlist; HBA_ptr; HBA_ptr = HBA_ptr->next) {
			if (HBA_ptr->host_no == host) {
				break;
			}
		}
		err = -ENXIO;
		if (!HBA_ptr)
			goto out;

		for (scd = HBA_ptr->host_queue; scd; scd = scd->next) {
			if ((scd->channel == channel
			     && scd->id == id
			     && scd->lun == lun)) {
				break;
			}
		}

		err = -ENOSYS;
		if (scd)
			goto out;	/* We do not yet support unplugging */

		scan_scsis(HBA_ptr, 1, channel, id, lun);

		/* FIXME (DB) This assumes that the queue_depth routines can be used
		   in this context as well, while they were all designed to be
		   called only once after the detect routine. (DB) */
		/* queue_depth routine moved to inside scan_scsis(,1,,,) so
		   it is called before build_commandblocks() */

		err = length;
		goto out;
	}
	/*
	 * Usage: echo "scsi remove-single-device 0 1 2 3" >/proc/scsi/scsi
	 * with  "0 1 2 3" replaced by your "Host Channel Id Lun".
	 *
	 * Consider this feature pre-BETA.
	 *
	 *     CAUTION: This is not for hotplugging your peripherals. As
	 *     SCSI was not designed for this you could damage your
	 *     hardware and thoroughly confuse the SCSI subsystem.
	 *
	 */
	else if (!strncmp("remove-single-device", buffer + 5, 20)) {
		p = buffer + 26;

		host = simple_strtoul(p, &p, 0);
		channel = simple_strtoul(p + 1, &p, 0);
		id = simple_strtoul(p + 1, &p, 0);
		lun = simple_strtoul(p + 1, &p, 0);