cciss: Fix warnings (and bug on 1TB discs)

CCISS was producing warnings about shifts being greater than the size of the type and pointers being of incompatible type. Turns out this is because it's calling do_div on a 32-bit quantity. Upon further investigation, the sector_t total_size is being assigned to an int, and then we're calling do_div on that int. Obviously, sector_div is called for here, and I took the chance to refactor the code a little.

drivers/block/cciss.c +9 -14

index dcccaf2..bc66026 100644
@@ -1923,7 +1923,6 @@ static void cciss_geometry_inquiry(int c
 {
 	int return_code;
 	unsigned long t;
-	unsigned long rem;
 
 	memset(inq_buff, 0, sizeof(InquiryData_struct));
 	if (withirq)

@@ -1939,26 +1938,23 @@ static void cciss_geometry_inquiry(int c
 			printk(KERN_WARNING
 			       "cciss: reading geometry failed, volume "
 			       "does not support reading geometry\n");
-			drv->block_size = block_size;
-			drv->nr_blocks = total_size;
 			drv->heads = 255;
 			drv->sectors = 32;	// Sectors per track
-			t = drv->heads * drv->sectors;
-			drv->cylinders = total_size;
-			rem = do_div(drv->cylinders, t);
 		} else {
-			drv->block_size = block_size;
-			drv->nr_blocks = total_size;
 			drv->heads = inq_buff->data_byte[6];
 			drv->sectors = inq_buff->data_byte[7];
 			drv->cylinders = (inq_buff->data_byte[4] & 0xff) << 8;
 			drv->cylinders += inq_buff->data_byte[5];
 			drv->raid_level = inq_buff->data_byte[8];
-			t = drv->heads * drv->sectors;
-			if (t > 1) {
-				drv->cylinders = total_size;
-				rem = do_div(drv->cylinders, t);
-			}
+		}
+		drv->block_size = block_size;
+		drv->nr_blocks = total_size;
+		t = drv->heads * drv->sectors;
+		if (t > 1) {
+			unsigned rem = sector_div(total_size, t);
+			if (rem)
+				total_size++;
+			drv->cylinders = total_size;
 		}
 	} else {		/* Get geometry failed */
 		printk(KERN_WARNING "cciss: reading geometry failed\n");
-

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Quoted 1 line

CCISS was producing warnings about shifts being greater

than the size

Quoted 1 line

of the type and pointers being of incompatible type. Turns

out this

Quoted 3 lines

is because it's calling do_div on a 32-bit quantity. Upon further investigation, the sector_t total_size is being assigned to an int, and then we're calling do_div on that int. Obviously,

sector_div is

Quoted 1 line

called for here, and I took the chance to refactor the code

a little.

Oops, forgot:

Signed-off-by Matthew Wilcox <[email protected]>

Quoted 19 lines

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

dcccaf2..bc66026 100644

drivers/block/cciss.c +0 -3

@@ -1923,7 +1923,6 @@ static void cciss_geometry_inquiry(int c  {
 	int return_code;
 	unsigned long t;
-	unsigned long rem;
 
 	memset(inq_buff, 0, sizeof(InquiryData_struct));
 	if (withirq)

@@ -1939,26 +1938,23 @@ static void cciss_geometry_inquiry(int c
 			printk(KERN_WARNING
 			       "cciss: reading geometry failed, volume "
 			       "does not support reading geometry\n");
-			drv->block_size = block_size;
-			drv->nr_blocks = total_size;
 			drv->heads = 255;

drivers/block/cciss.c static void cciss_geometry_inquiry(int c · line 1946

Quoted 10 lines

drivers/block/cciss.c +0 -5

 			drv->sectors = 32;	// Sectors per track
-			t = drv->heads * drv->sectors;
-			drv->cylinders = total_size;
-			rem = do_div(drv->cylinders, t);
 		} else {
-			drv->block_size = block_size;
-			drv->nr_blocks = total_size;
 			drv->heads = inq_buff->data_byte[6];
 			drv->sectors = inq_buff->data_byte[7];
 			drv->cylinders = 

(inq_buff->data_byte[4] & 0xff) << 8;

Quoted 20 lines

drivers/block/cciss.c +9 -6

 			drv->cylinders += inq_buff->data_byte[5];
 			drv->raid_level = inq_buff->data_byte[8];
-			t = drv->heads * drv->sectors;
-			if (t > 1) {
-				drv->cylinders = total_size;
-				rem = do_div(drv->cylinders, t);
-			}
+		}
+		drv->block_size = block_size;
+		drv->nr_blocks = total_size;
+		t = drv->heads * drv->sectors;
+		if (t > 1) {
+			unsigned rem = sector_div(total_size, t);
+			if (rem)
+				total_size++;
+			drv->cylinders = total_size;
 		}
 	} else {		/* Get geometry failed */
 		printk(KERN_WARNING "cciss: reading geometry failed\n");
-

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