[PATCH] cciss: fix unlikely startup problem

Patch from Stephen Cameron <steve.cameron@hp.com>


* Make cciss driver wait longer for board to enter simple mode to
  handle an unlikely corner case.  (Hot replace of failed 144GB
  drive in RAID 5 set at just the wrong time prior to driver loading
  can make the board take a longer than usual time to go into "simple
  mode".  Without the patch, the driver gives up too early, and consequently
  doesn't work.  (A reboot will generally "fix" it.)  This patch avoids
  the problem.
* Fix a couple ioctls to return EAGAIN instead of inappropriate EFAULT.

drivers/block/cciss.c

@@ -87,7 +87,8 @@ static struct board_type products[] = {
 };
 
 /* How long to wait (in millesconds) for board to go into simple mode */
-#define MAX_CONFIG_WAIT 1000 
+#define MAX_CONFIG_WAIT 30000 
+#define MAX_IOCTL_CONFIG_WAIT 1000
 
 #define READ_AHEAD 	 128
 #define NR_CMDS		 384 /* #commands that can be outstanding */
@@ -467,8 +468,7 @@ static int cciss_ioctl(struct inode *inode, struct file *filep,
                         &(c->cfgtable->HostWrite.CoalIntCount));
 		writel( CFGTBL_ChangeReq, c->vaddr + SA5_DOORBELL);
 
-		for(i=0;i<MAX_CONFIG_WAIT;i++)
-		{
+		for(i=0;i<MAX_IOCTL_CONFIG_WAIT;i++) {
 			if (!(readl(c->vaddr + SA5_DOORBELL) 
 					& CFGTBL_ChangeReq))
 				break;
@@ -476,8 +476,8 @@ static int cciss_ioctl(struct inode *inode, struct file *filep,
 			udelay(1000);
 		}	
 		spin_unlock_irqrestore(CCISS_LOCK(ctlr), flags);
-		if (i >= MAX_CONFIG_WAIT)
-			return( -EFAULT);
+		if (i >= MAX_IOCTL_CONFIG_WAIT)
+			return -EAGAIN;
                 return(0);
         }
 	case CCISS_GETNODENAME:
@@ -514,8 +514,7 @@ static int cciss_ioctl(struct inode *inode, struct file *filep,
 			
 		writel( CFGTBL_ChangeReq, c->vaddr + SA5_DOORBELL);
 
-		for(i=0;i<MAX_CONFIG_WAIT;i++)
-		{
+		for(i=0;i<MAX_IOCTL_CONFIG_WAIT;i++) {
 			if (!(readl(c->vaddr + SA5_DOORBELL) 
 					& CFGTBL_ChangeReq))
 				break;
@@ -523,8 +522,8 @@ static int cciss_ioctl(struct inode *inode, struct file *filep,
 			udelay(1000);
 		}	
 		spin_unlock_irqrestore(CCISS_LOCK(ctlr), flags);
-		if (i >= MAX_CONFIG_WAIT)
-			return( -EFAULT);
+		if (i >= MAX_IOCTL_CONFIG_WAIT)
+			return -EAGAIN;
                 return(0);
         }
 
@@ -2038,12 +2037,15 @@ static int cciss_pci_init(ctlr_info_t *c, struct pci_dev *pdev)
 		&(c->cfgtable->HostWrite.TransportRequest));
 	writel( CFGTBL_ChangeReq, c->vaddr + SA5_DOORBELL);
 
-	for(i=0;i<MAX_CONFIG_WAIT;i++)
-	{
+	/* under certain very rare conditions, this can take awhile.
+	 * (e.g.: hot replace a failed 144GB drive in a RAID 5 set right
+	 * as we enter this code.) */
+	for(i=0;i<MAX_CONFIG_WAIT;i++) {
 		if (!(readl(c->vaddr + SA5_DOORBELL) & CFGTBL_ChangeReq))
 			break;
 		/* delay and try again */
-		udelay(1000);
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(10);
 	}	
 
 #ifdef CCISS_DEBUG