drivers/block: Use DIV_ROUND_UP

The kernel.h macro DIV_ROUND_UP performs the computation (((n) + (d) - 1) /
(d)) but is perhaps more readable.

An extract of the semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@haskernel@
@@

#include <linux/kernel.h>

@depends on haskernel@
expression n,d;
@@

(
- (n + d - 1) / d
+ DIV_ROUND_UP(n,d)
|
- (n + (d - 1)) / d
+ DIV_ROUND_UP(n,d)
)

@depends on haskernel@
expression n,d;
@@

- DIV_ROUND_UP((n),d)
+ DIV_ROUND_UP(n,d)

@depends on haskernel@
expression n,d;
@@

- DIV_ROUND_UP(n,(d))
+ DIV_ROUND_UP(n,d)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: <mike.miller@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/block/cpqarray.c b/drivers/block/cpqarray.c
index 09c1434..3d967525 100644
--- a/drivers/block/cpqarray.c
+++ b/drivers/block/cpqarray.c
@@ -424,7 +424,7 @@
 		hba[i]->pci_dev, NR_CMDS * sizeof(cmdlist_t),
 		&(hba[i]->cmd_pool_dhandle));
 	hba[i]->cmd_pool_bits = kcalloc(
-		(NR_CMDS+BITS_PER_LONG-1)/BITS_PER_LONG, sizeof(unsigned long),
+		DIV_ROUND_UP(NR_CMDS, BITS_PER_LONG), sizeof(unsigned long),
 		GFP_KERNEL);
 
 	if (!hba[i]->cmd_pool_bits || !hba[i]->cmd_pool)