drivers/block/cciss.c: fix check-after-use

-----Original Message-----
From: Adrian Bunk [mailto:[email protected]]
Sent: Monday, July 30, 2007 5:28 PM
To: Miller, Mike (OS Dev); Jens Axboe
Cc: ISS StorageDev; [email protected]
Subject: [2.6 patch] drivers/block/cciss.c: fix check-after-use

The Coverity checker spotted that we have already oops'ed if "disk" was NULL.

Since "disk" being NULL seems impossible at this point this patch removes the NULL check.

Signed-off-by Adrian Bunk <[email protected]>

---

 drivers/block/cciss.c |   56 
++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 29 deletions(-)

--- linux-2.6.23-rc1-mm1/drivers/block/cciss.c.old

2007-07-30 02:27:15.000000000 +0200
+++ linux-2.6.23-rc1-mm1/drivers/block/cciss.c	
2007-07-30 02:28:28.000000000 +0200

drivers/block/cciss.c renamed from drivers/block/cciss.c.old +0 -0

@@ -1569,66 +1569,64 @@ static int deregister_disk(struct gendis
 	ctlr_info_t *h = get_host(disk);
 
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
 
 	/* make sure logical volume is NOT is use */
 	if (clear_all || (h->gendisk[0] == disk)) {
 		if (drv->usage_count > 1)
 			return -EBUSY;
 	} else if (drv->usage_count > 0)
 		return -EBUSY;
 
 	/* 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.

drivers/block/cciss.c renamed from drivers/block/cciss.c.old +0 -7

 	 */
 	if (h->gendisk[0] != disk) {
-		if (disk) {
-			struct request_queue *q = disk->queue;
-			if (disk->flags & GENHD_FL_UP)
-				del_gendisk(disk);
-			if (q) {
-				blk_cleanup_queue(q);
-				/* Set drv->queue to NULL so 

that we do not try

(quoted diff) +0 -1

-				 * to call blk_start_queue on 

this queue in the

drivers/block/cciss.c renamed from drivers/block/cciss.c.old +0 -5

-				 * interrupt handler
-				 */
-				drv->queue = NULL;
-			}
-			/* If clear_all is set then we are 

deleting the logical

(quoted diff) +0 -2

-			 * drive, not just refreshing its info. 
 For drives
-			 * other than disk 0 we will call 

put_disk. We do not

(quoted diff) +0 -1

-			 * do this for disk 0 as we need it to 

be able to

drivers/block/cciss.c renamed from drivers/block/cciss.c.old +22 -3

-			 * configure the controller.
+		struct request_queue *q = disk->queue;
+		if (disk->flags & GENHD_FL_UP)
+			del_gendisk(disk);
+		if (q) {
+			blk_cleanup_queue(q);
+			/* Set drv->queue to NULL so that we do not try
+			 * to call blk_start_queue on this queue in the
+			 * interrupt handler
+			 */
+			drv->queue = NULL;
+		}
+		/* If clear_all is set then we are deleting the logical
+		 * drive, not just refreshing its info.  For drives
+		 * other than disk 0 we will call put_disk.  We do not
+		 * do this for disk 0 as we need it to be able to
+		 * configure the controller.
+		*/
+		if (clear_all){
+			/* This isn't pretty, but we need to find the
+			 * disk in our array and NULL our the pointer.
+			 * This is so that we will call alloc_disk if
+			 * this index is used again later.
 			*/
-			if (clear_all){
-				/* This isn't pretty, but we 

need to find the

(quoted diff) +0 -1

-				 * disk in our array and NULL 

our the pointer.

(quoted diff) +0 -1

-				 * This is so that we will call 

alloc_disk if

drivers/block/cciss.c renamed from drivers/block/cciss.c.old +5 -8

-				 * this index is used again later.
-				*/
-				for (i=0; i < CISS_MAX_LUN; i++){
-					if(h->gendisk[i] == disk){
-						h->gendisk[i] = NULL;
-						break;
-					}
+			for (i=0; i < CISS_MAX_LUN; i++){
+				if(h->gendisk[i] == disk){
+					h->gendisk[i] = NULL;
+					break;
 				}
-				put_disk(disk);
 			}
+			put_disk(disk);
 		}
 	} else {
 		set_capacity(disk, 0);
 	}
 
 	--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

drivers/block/cciss.c renamed from drivers/block/cciss.c.old +0 -0

 				 * array is free.
 				 */