[PATCH] cciss: new disk register/deregister routines

This patch removes a couple of functions dealing with configuration and
replaces them with new functions.  This implementation fixes some bugs
associated with the ACUXE.  It also allows a logical volume to be removed from
the middle without deleting all volumes behind it.

If a user has 5 logical volumes and decides he wants to reconfigure volume
number 3, he can now do that without removing volumes 4 & 5 first.  This code
has been tested in our labs against all application software.
Signed-off-by: Chase Maupin <chase.maupin@hp.com>
Signed-off-by: Mike Miller <mike.miller@hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/block/cciss.c

@@ -155,15 +155,24 @@ static int cciss_ioctl(struct inode *inode, struct file *filep,
 
 static int revalidate_allvol(ctlr_info_t *host);
 static int cciss_revalidate(struct gendisk *disk);
-static int deregister_disk(struct gendisk *disk);
-static int register_new_disk(ctlr_info_t *h);
+static int rebuild_lun_table(ctlr_info_t *h, struct gendisk *del_disk);
+static int deregister_disk(struct gendisk *disk, drive_info_struct *drv, int clear_all);
 
+static void cciss_read_capacity(int ctlr, int logvol, ReadCapdata_struct *buf,
+	int withirq, unsigned int *total_size, unsigned int *block_size);
+static void cciss_geometry_inquiry(int ctlr, int logvol,
+			int withirq, unsigned int total_size,
+			unsigned int block_size, InquiryData_struct *inq_buff,
+			drive_info_struct *drv);
 static void cciss_getgeometry(int cntl_num);
 
 static void start_io( ctlr_info_t *h);
 static int sendcmd( __u8 cmd, int ctlr, void *buff, size_t size,
 	unsigned int use_unit_num, unsigned int log_unit, __u8 page_code,
 	unsigned char *scsi3addr, int cmd_type);
+static int sendcmd_withirq(__u8	cmd, int ctlr, void *buff, size_t size,
+	unsigned int use_unit_num, unsigned int log_unit, __u8	page_code,
+	int cmd_type);
 
 #ifdef CONFIG_PROC_FS
 static int cciss_proc_get_info(char *buffer, char **start, off_t offset, 
@@ -280,7 +289,7 @@ static int cciss_proc_get_info(char *buffer, char **start, off_t offset,
 	for(i=0; i<=h->highest_lun; i++) {
 
                 drv = &h->drv[i];
-		if (drv->block_size == 0)
+		if (drv->heads == 0)
 			continue;
 
 		vol_sz = drv->nr_blocks;
@@ -471,6 +480,8 @@ static int cciss_open(struct inode *inode, struct file *filep)
 	if (host->busy_initializing)
 		return -EBUSY;
 
+	if (host->busy_initializing || drv->busy_configuring)
+		return -EBUSY;
 	/*
 	 * Root is allowed to open raw volume zero even if it's not configured
 	 * so array config can still work. Root is also allowed to open any
@@ -814,10 +825,10 @@ static int cciss_ioctl(struct inode *inode, struct file *filep,
  		return(0);
  	}
 	case CCISS_DEREGDISK:
-		return deregister_disk(disk);
+		return rebuild_lun_table(host, disk);
 
 	case CCISS_REGNEWD:
-		return register_new_disk(host);
+		return rebuild_lun_table(host, NULL);
 
 	case CCISS_PASSTHRU:
 	{
@@ -1161,48 +1172,323 @@ static int revalidate_allvol(ctlr_info_t *host)
         return 0;
 }
 
-static int deregister_disk(struct gendisk *disk)
+/* This function will check the usage_count of the drive to be updated/added.
+ * If the usage_count is zero then the drive information will be updated and
+ * the disk will be re-registered with the kernel.  If not then it will be
+ * left alone for the next reboot.  The exception to this is disk 0 which
+ * will always be left registered with the kernel since it is also the
+ * controller node.  Any changes to disk 0 will show up on the next
+ * reboot.
+*/
+static void cciss_update_drive_info(int ctlr, int drv_index)
+  {
+	ctlr_info_t *h = hba[ctlr];
+	struct gendisk *disk;
+	ReadCapdata_struct *size_buff = NULL;
+	InquiryData_struct *inq_buff = NULL;
+	unsigned int block_size;
+	unsigned int total_size;
+	unsigned long flags = 0;
+	int ret = 0;
+
+	/* if the disk already exists then deregister it before proceeding*/
+	if (h->drv[drv_index].raid_level != -1){
+		spin_lock_irqsave(CCISS_LOCK(h->ctlr), flags);
+		h->drv[drv_index].busy_configuring = 1;
+		spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+		ret = deregister_disk(h->gendisk[drv_index],
+			&h->drv[drv_index], 0);
+		h->drv[drv_index].busy_configuring = 0;
+	}
+
+	/* If the disk is in use return */
+	if (ret)
+		return;
+
+
+	/* Get information about the disk and modify the driver sturcture */
+	size_buff = kmalloc(sizeof( ReadCapdata_struct), GFP_KERNEL);
+        if (size_buff == NULL)
+		goto mem_msg;
+	inq_buff = kmalloc(sizeof( InquiryData_struct), GFP_KERNEL);
+	if (inq_buff == NULL)
+		goto mem_msg;
+
+	cciss_read_capacity(ctlr, drv_index, size_buff, 1,
+		&total_size, &block_size);
+	cciss_geometry_inquiry(ctlr, drv_index, 1, total_size, block_size,
+		inq_buff, &h->drv[drv_index]);
+
+	++h->num_luns;
+	disk = h->gendisk[drv_index];
+	set_capacity(disk, h->drv[drv_index].nr_blocks);
+
+
+	/* if it's the controller it's already added */
+	if (drv_index){
+		disk->queue = blk_init_queue(do_cciss_request, &h->lock);
+
+		/* Set up queue information */
+		disk->queue->backing_dev_info.ra_pages = READ_AHEAD;
+		blk_queue_bounce_limit(disk->queue, hba[ctlr]->pdev->dma_mask);
+
+		/* This is a hardware imposed limit. */
+		blk_queue_max_hw_segments(disk->queue, MAXSGENTRIES);
+
+		/* This is a limit in the driver and could be eliminated. */
+		blk_queue_max_phys_segments(disk->queue, MAXSGENTRIES);
+
+		blk_queue_max_sectors(disk->queue, 512);
+
+		disk->queue->queuedata = hba[ctlr];
+
+		blk_queue_hardsect_size(disk->queue,
+			hba[ctlr]->drv[drv_index].block_size);
+
+		h->drv[drv_index].queue = disk->queue;
+		add_disk(disk);
+	}
+
+freeret:
+	kfree(size_buff);
+	kfree(inq_buff);
+	return;
+mem_msg:
+	printk(KERN_ERR "cciss: out of memory\n");
+	goto freeret;
+}
+
+/* This function will find the first index of the controllers drive array
+ * that has a -1 for the raid_level and will return that index.  This is
+ * where new drives will be added.  If the index to be returned is greater
+ * than the highest_lun index for the controller then highest_lun is set
+ * to this new index.  If there are no available indexes then -1 is returned.
+*/
+static int cciss_find_free_drive_index(int ctlr)
+{
+	int i;
+
+	for (i=0; i < CISS_MAX_LUN; i++){
+		if (hba[ctlr]->drv[i].raid_level == -1){
+			if (i > hba[ctlr]->highest_lun)
+				hba[ctlr]->highest_lun = i;
+			return i;
+		}
+	}
+	return -1;
+}
+
+/* This function will add and remove logical drives from the Logical
+ * drive array of the controller and maintain persistancy of ordering
+ * so that mount points are preserved until the next reboot.  This allows
+ * for the removal of logical drives in the middle of the drive array
+ * without a re-ordering of those drives.
+ * INPUT
+ * h		= The controller to perform the operations on
+ * del_disk	= The disk to remove if specified.  If the value given
+ *		  is NULL then no disk is removed.
+*/
+static int rebuild_lun_table(ctlr_info_t *h, struct gendisk *del_disk)
 {
+	int ctlr = h->ctlr;
+	int num_luns;
+	ReportLunData_struct *ld_buff = NULL;
+	drive_info_struct *drv = NULL;
+	int return_code;
+	int listlength = 0;
+	int i;
+	int drv_found;
+	int drv_index = 0;
+	__u32 lunid = 0;
 	unsigned long flags;
+
+	/* Set busy_configuring flag for this operation */
+	spin_lock_irqsave(CCISS_LOCK(h->ctlr), flags);
+	if (h->num_luns >= CISS_MAX_LUN){
+		spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+		return -EINVAL;
+	}
+
+	if (h->busy_configuring){
+		spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+		return -EBUSY;
+	}
+	h->busy_configuring = 1;
+
+	/* if del_disk is NULL then we are being called to add a new disk
+	 * and update the logical drive table.  If it is not NULL then
+	 * we will check if the disk is in use or not.
+	 */
+	if (del_disk != NULL){
+		drv = get_drv(del_disk);
+		drv->busy_configuring = 1;
+		spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+		return_code = deregister_disk(del_disk, drv, 1);
+		drv->busy_configuring = 0;
+		h->busy_configuring = 0;
+		return return_code;
+	} else {
+		spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+		if (!capable(CAP_SYS_RAWIO))
+			return -EPERM;
+
+		ld_buff = kzalloc(sizeof(ReportLunData_struct), GFP_KERNEL);
+		if (ld_buff == NULL)
+			goto mem_msg;
+
+		return_code = sendcmd_withirq(CISS_REPORT_LOG, ctlr, ld_buff,
+				sizeof(ReportLunData_struct), 0, 0, 0,
+				TYPE_CMD);
+
+		if (return_code == IO_OK){
+			listlength |= (0xff & (unsigned int)(ld_buff->LUNListLength[0])) << 24;
+			listlength |= (0xff & (unsigned int)(ld_buff->LUNListLength[1])) << 16;
+			listlength |= (0xff & (unsigned int)(ld_buff->LUNListLength[2])) << 8;
+			listlength |= 0xff & (unsigned int)(ld_buff->LUNListLength[3]);
+		} else{ /* reading number of logical volumes failed */
+			printk(KERN_WARNING "cciss: report logical volume"
+				" command failed\n");
+			listlength = 0;
+			goto freeret;
+		}
+
+		num_luns = listlength / 8;	/* 8 bytes per entry */
+		if (num_luns > CISS_MAX_LUN){
+			num_luns = CISS_MAX_LUN;
+			printk(KERN_WARNING "cciss: more luns configured"
+				" on controller than can be handled by"
+				" this driver.\n");
+		}
+
+		/* Compare controller drive array to drivers drive array.
+	 	* Check for updates in the drive information and any new drives
+	 	* on the controller.
+	 	*/
+		for (i=0; i < num_luns; i++){
+			int j;
+
+			drv_found = 0;
+
+	  		lunid = (0xff &
+				(unsigned int)(ld_buff->LUN[i][3])) << 24;
+        		lunid |= (0xff &
+				(unsigned int)(ld_buff->LUN[i][2])) << 16;
+        		lunid |= (0xff &
+				(unsigned int)(ld_buff->LUN[i][1])) << 8;
+        		lunid |= 0xff &
+				(unsigned int)(ld_buff->LUN[i][0]);
+
+			/* Find if the LUN is already in the drive array
+			 * of the controller.  If so then update its info
+			 * if not is use.  If it does not exist then find
+			 * the first free index and add it.
+			*/
+			for (j=0; j <= h->highest_lun; j++){
+				if (h->drv[j].LunID == lunid){
+					drv_index = j;
+					drv_found = 1;
+				}
+			}
+
+			/* check if the drive was found already in the array */
+			if (!drv_found){
+				drv_index = cciss_find_free_drive_index(ctlr);
+				if (drv_index == -1)
+					goto freeret;
+
+			}
+			h->drv[drv_index].LunID = lunid;
+			cciss_update_drive_info(ctlr, drv_index);
+		} /* end for */
+	} /* end else */
+
+freeret:
+	kfree(ld_buff);
+	h->busy_configuring = 0;
+	/* We return -1 here to tell the ACU that we have registered/updated
+	 * all of the drives that we can and to keep it from calling us
+	 * additional times.
+	*/
+	return -1;
+mem_msg:
+	printk(KERN_ERR "cciss: out of memory\n");
+	goto freeret;
+}
+
+/* This function will deregister the disk and it's queue from the
+ * kernel.  It must be called with the controller lock held and the
+ * drv structures busy_configuring flag set.  It's parameters are:
+ *
+ * disk = This is the disk to be deregistered
+ * drv  = This is the drive_info_struct associated with the disk to be
+ *        deregistered.  It contains information about the disk used
+ *        by the driver.
+ * clear_all = This flag determines whether or not the disk information
+ *             is going to be completely cleared out and the highest_lun
+ *             reset.  Sometimes we want to clear out information about
+ *             the disk in preperation for re-adding it.  In this case
+ *             the highest_lun should be left unchanged and the LunID
+ *             should not be cleared.
+*/
+static int deregister_disk(struct gendisk *disk, drive_info_struct *drv,
+			   int clear_all)
+{
 	ctlr_info_t *h = get_host(disk);
-	drive_info_struct *drv = get_drv(disk);
-	int ctlr = h->ctlr;
 
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
 
-	spin_lock_irqsave(CCISS_LOCK(ctlr), flags);
 	/* make sure logical volume is NOT is use */
-	if( drv->usage_count > 1) {
-		spin_unlock_irqrestore(CCISS_LOCK(ctlr), flags);
+	if(clear_all || (h->gendisk[0] == disk)) {
+	if (drv->usage_count > 1)
                 return -EBUSY;
 	}
-	drv->usage_count++;
-	spin_unlock_irqrestore(CCISS_LOCK(ctlr), flags);
+        else
+        	if( drv->usage_count > 0 )
+                	return -EBUSY;
 
-	/* invalidate the devices and deregister the disk */ 
-	if (disk->flags & GENHD_FL_UP)
+	/* invalidate the devices and deregister the disk.  If it is disk
+	 * zero do not deregister it but just zero out it's values.  This
+	 * allows us to delete disk zero but keep the controller registered.
+	*/
+	if (h->gendisk[0] != disk){
+		if (disk->flags & GENHD_FL_UP){
+			blk_cleanup_queue(disk->queue);
 		del_gendisk(disk);
+			drv->queue = NULL;
+		}
+	}
+
+	--h->num_luns;
+	/* zero out the disk size info */
+	drv->nr_blocks = 0;
+	drv->block_size = 0;
+	drv->heads = 0;
+	drv->sectors = 0;
+	drv->cylinders = 0;
+	drv->raid_level = -1;	/* This can be used as a flag variable to
+				 * indicate that this element of the drive
+				 * array is free.
+				*/
+
+	if (clear_all){
 	/* check to see if it was the last disk */
 	if (drv == h->drv + h->highest_lun) {
 		/* if so, find the new hightest lun */
 		int i, newhighest =-1;
 		for(i=0; i<h->highest_lun; i++) {
 			/* if the disk has size > 0, it is available */
-			if (h->drv[i].nr_blocks)
+				if (h->drv[i].heads)
 				newhighest = i;
 		}
 		h->highest_lun = newhighest;
-				
 	}
-	--h->num_luns;
-	/* zero out the disk size info */ 
-	drv->nr_blocks = 0;
-	drv->block_size = 0;
-	drv->cylinders = 0;
+
 	drv->LunID = 0;
+	}
 	return(0);
 }
+
 static int fill_cmd(CommandList_struct *c, __u8 cmd, int ctlr, void *buff,
 	size_t size,
 	unsigned int use_unit_num, /* 0: address the controller,
@@ -1513,164 +1799,6 @@ cciss_read_capacity(int ctlr, int logvol, ReadCapdata_struct *buf,
 	return;
 }
 
-static int register_new_disk(ctlr_info_t *h)
-{
-        struct gendisk *disk;
-	int ctlr = h->ctlr;
-        int i;
-	int num_luns;
-	int logvol;
-	int new_lun_found = 0;
-	int new_lun_index = 0;
-	int free_index_found = 0;
-	int free_index = 0;
-	ReportLunData_struct *ld_buff = NULL;
-	ReadCapdata_struct *size_buff = NULL;
-	InquiryData_struct *inq_buff = NULL;
-	int return_code;
-	int listlength = 0;
-	__u32 lunid = 0;
-	unsigned int block_size;
-	unsigned int total_size;
-
-        if (!capable(CAP_SYS_RAWIO))
-                return -EPERM;
-	/* if we have no space in our disk array left to add anything */
-	if(  h->num_luns >= CISS_MAX_LUN)
-		return -EINVAL;
-	
-	ld_buff = kmalloc(sizeof(ReportLunData_struct), GFP_KERNEL);
-	if (ld_buff == NULL)
-		goto mem_msg;
-	memset(ld_buff, 0, sizeof(ReportLunData_struct));
-	size_buff = kmalloc(sizeof( ReadCapdata_struct), GFP_KERNEL);
-        if (size_buff == NULL)
-		goto mem_msg;
-	inq_buff = kmalloc(sizeof( InquiryData_struct), GFP_KERNEL);
-        if (inq_buff == NULL)
-		goto mem_msg;
-	
-	return_code = sendcmd_withirq(CISS_REPORT_LOG, ctlr, ld_buff, 
-			sizeof(ReportLunData_struct), 0, 0, 0, TYPE_CMD);
-
-	if( return_code == IO_OK)
-	{
-		
-		// printk("LUN Data\n--------------------------\n");
-
-		listlength |= (0xff & (unsigned int)(ld_buff->LUNListLength[0])) << 24;
-		listlength |= (0xff & (unsigned int)(ld_buff->LUNListLength[1])) << 16;
-		listlength |= (0xff & (unsigned int)(ld_buff->LUNListLength[2])) << 8;	
-		listlength |= 0xff & (unsigned int)(ld_buff->LUNListLength[3]);
-	} else /* reading number of logical volumes failed */
-	{
-		printk(KERN_WARNING "cciss: report logical volume"
-			" command failed\n");
-		listlength = 0;
-		goto free_err;
-	}
-	num_luns = listlength / 8; // 8 bytes pre entry
-	if (num_luns > CISS_MAX_LUN)
-	{
-		num_luns = CISS_MAX_LUN;
-	}
-#ifdef CCISS_DEBUG
-	printk(KERN_DEBUG "Length = %x %x %x %x = %d\n", ld_buff->LUNListLength[0],
-		ld_buff->LUNListLength[1], ld_buff->LUNListLength[2],
-		ld_buff->LUNListLength[3],  num_luns);
-#endif 
-	for(i=0; i<  num_luns; i++)
-	{
-		int j;
-		int lunID_found = 0;
-
-	  	lunid = (0xff & (unsigned int)(ld_buff->LUN[i][3])) << 24;
-        	lunid |= (0xff & (unsigned int)(ld_buff->LUN[i][2])) << 16;
-        	lunid |= (0xff & (unsigned int)(ld_buff->LUN[i][1])) << 8;
-        	lunid |= 0xff & (unsigned int)(ld_buff->LUN[i][0]);
-		
- 		/* check to see if this is a new lun */ 
-		for(j=0; j <= h->highest_lun; j++)
-		{
-#ifdef CCISS_DEBUG
-			printk("Checking %d %x against %x\n", j,h->drv[j].LunID,
-						lunid);
-#endif /* CCISS_DEBUG */
-			if (h->drv[j].LunID == lunid)
-			{
-				lunID_found = 1;
-				break;
-			}
-			
-		}
-		if( lunID_found == 1)
-			continue;
-		else
-		{	/* It is the new lun we have been looking for */
-#ifdef CCISS_DEBUG
-			printk("new lun found at %d\n", i);
-#endif /* CCISS_DEBUG */
-			new_lun_index = i;
-			new_lun_found = 1;
-			break;	
-		}
-	 }
-	 if (!new_lun_found)
-	 {
-		printk(KERN_WARNING "cciss:  New Logical Volume not found\n");
-		goto free_err;
-	 }
-	 /* Now find the free index 	*/
-	for(i=0; i <CISS_MAX_LUN; i++)
-	{
-#ifdef CCISS_DEBUG
-		printk("Checking Index %d\n", i);
-#endif /* CCISS_DEBUG */
-		if(h->drv[i].LunID == 0)
-		{
-#ifdef CCISS_DEBUG
-			printk("free index found at %d\n", i);
-#endif /* CCISS_DEBUG */
-			free_index_found = 1;
-			free_index = i;
-			break;
-		}
-	}
-	if (!free_index_found)
-	{
-		printk(KERN_WARNING "cciss: unable to find free slot for disk\n");
-		goto free_err;
-         }
-
-	logvol = free_index;
-	h->drv[logvol].LunID = lunid;
-		/* there could be gaps in lun numbers, track hightest */
-	if(h->highest_lun < lunid)
-		h->highest_lun = logvol;
-	cciss_read_capacity(ctlr, logvol, size_buff, 1,
-		&total_size, &block_size);
-	cciss_geometry_inquiry(ctlr, logvol, 1, total_size, block_size,
-			inq_buff, &h->drv[logvol]);
-	h->drv[logvol].usage_count = 0;
-	++h->num_luns;
-	/* setup partitions per disk */
-        disk = h->gendisk[logvol];
-	set_capacity(disk, h->drv[logvol].nr_blocks);
-	/* if it's the controller it's already added */
-	if(logvol)
-		add_disk(disk);
-freeret:
-	kfree(ld_buff);
-	kfree(size_buff);
-	kfree(inq_buff);
-	return (logvol);
-mem_msg:
-	printk(KERN_ERR "cciss: out of memory\n");
-free_err:
-	logvol = -1;
-	goto freeret;
-}
-
 static int cciss_revalidate(struct gendisk *disk)
 {
 	ctlr_info_t *h = get_host(disk);
@@ -2652,12 +2780,16 @@ static void cciss_getgeometry(int cntl_num)
 #endif /* CCISS_DEBUG */
 
 	hba[cntl_num]->highest_lun = hba[cntl_num]->num_luns-1;
-	for(i=0; i<  hba[cntl_num]->num_luns; i++)
+//	for(i=0; i<  hba[cntl_num]->num_luns; i++)
+	for(i=0; i < CISS_MAX_LUN; i++)
 	{
-
-	  	lunid = (0xff & (unsigned int)(ld_buff->LUN[i][3])) << 24;
-        	lunid |= (0xff & (unsigned int)(ld_buff->LUN[i][2])) << 16;
-        	lunid |= (0xff & (unsigned int)(ld_buff->LUN[i][1])) << 8;
+		if (i < hba[cntl_num]->num_luns){
+		  	lunid = (0xff & (unsigned int)(ld_buff->LUN[i][3]))
+				 << 24;
+        		lunid |= (0xff & (unsigned int)(ld_buff->LUN[i][2]))
+				 << 16;
+        		lunid |= (0xff & (unsigned int)(ld_buff->LUN[i][1]))
+				 << 8;
         	lunid |= 0xff & (unsigned int)(ld_buff->LUN[i][0]);
 		
 		hba[cntl_num]->drv[i].LunID = lunid;
@@ -2665,13 +2797,18 @@ static void cciss_getgeometry(int cntl_num)
 
 #ifdef CCISS_DEBUG
 	  	printk(KERN_DEBUG "LUN[%d]:  %x %x %x %x = %x\n", i, 
-		ld_buff->LUN[i][0], ld_buff->LUN[i][1],ld_buff->LUN[i][2], 
-		ld_buff->LUN[i][3], hba[cntl_num]->drv[i].LunID);
+			ld_buff->LUN[i][0], ld_buff->LUN[i][1],
+			ld_buff->LUN[i][2], ld_buff->LUN[i][3],
+			hba[cntl_num]->drv[i].LunID);
 #endif /* CCISS_DEBUG */
 		cciss_read_capacity(cntl_num, i, size_buff, 0,
 			&total_size, &block_size);
-		cciss_geometry_inquiry(cntl_num, i, 0, total_size, block_size,
-			inq_buff, &hba[cntl_num]->drv[i]);
+			cciss_geometry_inquiry(cntl_num, i, 0, total_size,
+				block_size, inq_buff, &hba[cntl_num]->drv[i]);
+		} else {
+			/* initialize raid_level to indicate a free space */
+			hba[cntl_num]->drv[i].raid_level = -1;
+		}
 	}
 	kfree(ld_buff);
 	kfree(size_buff);

drivers/block/cciss.h

@@ -35,7 +35,13 @@ typedef struct _drive_info_struct
 	int 	heads;
 	int	sectors;
 	int 	cylinders;
-	int	raid_level;
+	int	raid_level; /* set to -1 to indicate that
+			     * the drive is not in use/configured
+			    */
+	int	busy_configuring; /*This is set when the drive is being removed
+				   *to prevent it from being opened or it's queue
+				   *from being started.
+				  */
 } drive_info_struct;
 
 struct ctlr_info