[PATCH v2 2/7] staging: most: Using macro DIV_ROUND_UP

* [PATCH v2 2/7] staging: most: Using macro DIV_ROUND_UP
@ 2017-02-22  9:10 simran singhal
  2017-02-22  9:27 ` [Outreachy kernel] " Julia Lawall
  0 siblings, 1 reply; 5+ messages in thread
From: simran singhal @ 2017-02-22  9:10 UTC (permalink / raw)
  To: gregkh; +Cc: devel, linux-kernel, outreachy-kernel

The macro DIV_ROUND_UP performs the computation (((n) + (d) - 1) /(d)).
It clarifies the divisor calculations. This occurence was detected using
the coccinelle script:

@@
expression e1;
expression e2;
@@
(
- ((e1) + e2 - 1) / (e2)
+ DIV_ROUND_UP(e1,e2)
|
- ((e1) + (e2 - 1)) / (e2)
+ DIV_ROUND_UP(e1,e2)
)

Signed-off-by: simran singhal <singhalsimran0@gmail.com>
---
 
 v2:
   -Included kernel.h as DIV_ROUND_UP is defined in it,
    before it was giving compilation error.

 drivers/staging/most/hdm-dim2/dim2_hal.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/most/hdm-dim2/dim2_hal.c b/drivers/staging/most/hdm-dim2/dim2_hal.c
index 0b9816c..d604ec09 100644
--- a/drivers/staging/most/hdm-dim2/dim2_hal.c
+++ b/drivers/staging/most/hdm-dim2/dim2_hal.c
@@ -18,6 +18,7 @@
 #include "dim2_errors.h"
 #include "dim2_reg.h"
 #include <linux/stddef.h>
+#include <linux/kernel.h>
 
 /*
  * Size factor for isochronous DBR buffer.
@@ -49,7 +50,7 @@
 #define DBR_SIZE  (16 * 1024) /* specified by IP */
 #define DBR_BLOCK_SIZE  (DBR_SIZE / 32 / DBR_MAP_SIZE)
 
-#define ROUND_UP_TO(x, d)  (((x) + (d) - 1) / (d) * (d))
+#define ROUND_UP_TO(x, d)  (DIV_ROUND_UP(x, (d)) * (d))
 
 /* -------------------------------------------------------------------------- */
 /* generic helper functions and macros */
@@ -117,7 +118,7 @@ static int alloc_dbr(u16 size)
 		return DBR_SIZE; /* out of memory */
 
 	for (i = 0; i < DBR_MAP_SIZE; i++) {
-		u32 const blocks = (size + DBR_BLOCK_SIZE - 1) / DBR_BLOCK_SIZE;
+		u32 const blocks = DIV_ROUND_UP(size, DBR_BLOCK_SIZE);
 		u32 mask = ~((~(u32)0) << blocks);
 
 		do {
@@ -137,7 +138,7 @@ static int alloc_dbr(u16 size)
 static void free_dbr(int offs, int size)
 {
 	int block_idx = offs / DBR_BLOCK_SIZE;
-	u32 const blocks = (size + DBR_BLOCK_SIZE - 1) / DBR_BLOCK_SIZE;
+	u32 const blocks = DIV_ROUND_UP(size, DBR_BLOCK_SIZE);
 	u32 mask = ~((~(u32)0) << blocks);
 
 	mask <<= block_idx % 32;
-- 
2.7.4



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