在 2015/12/7 19:08, Ohad Ben-Cohen 写道:
> Hi,
>
> On Sun, Dec 6, 2015 at 12:33 PM, Zhaoxiu Zeng <zhaoxiu.z...@gmail.com> wrote:
>>
>> From: Zeng Zhaoxiu <zhaoxiu.z...@gmail.com>
>>
>> Signed-off-by: Zeng Zhaoxiu <zhaoxiu.z...@gmail.com>
>
> Please explain why do you think we should make this change.
is_power_of_2 is simple, and faster than "hweightN(x) == 1" on most
architectures.
And the "& 0xf" operation is unnecessary, we will check whether or not greater
than 8 behind.
>
> Btw, the original code used is_power_of_2, but we thought hweight is
> more explicit so it was adopted.
>
> Thanks,
> Ohad.
>
---
drivers/hwspinlock/omap_hwspinlock.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/hwspinlock/omap_hwspinlock.c
b/drivers/hwspinlock/omap_hwspinlock.c
index ad2f8ca..1848a4c 100644
--- a/drivers/hwspinlock/omap_hwspinlock.c
+++ b/drivers/hwspinlock/omap_hwspinlock.c
@@ -29,6 +29,7 @@
#include <linux/hwspinlock.h>
#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/log2.h>
#include "hwspinlock_internal.h"
@@ -125,7 +126,7 @@ static int omap_hwspinlock_probe(struct platform_device
*pdev)
goto iounmap_base;
/* one of the four lsb's must be set, and nothing else */
- if (hweight_long(i & 0xf) != 1 || i > 8) {
+ if (!is_power_of_2(i) || i > 8) {
ret = -EINVAL;
goto iounmap_base;
}
--
--
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