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Re: [PATCH 02/10] brcmstb_gisb: Replace "hweight_long(mask) != 1" with "!is_power_of_2(mask)"

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  Re: [PATCH 02/10] brcmstb_gisb: Replace "hweight_long(mask) != 1"  with "!is_power_of_2(mask)" Florian Fainelli <f.fainelli@gmail.com> - 2015-12-14 21:00 +0100

#1291512 — Re: [PATCH 02/10] brcmstb_gisb: Replace "hweight_long(mask) != 1" with "!is_power_of_2(mask)"

On 06/12/15 02:11, Zhaoxiu Zeng wrote:
> From: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>

is_power_of_2, AFAICT does not handle the case where the mask to be
tested for is zero, which is why I went with hweight_long() in the first
place.

Without further explanation as to whether we should prefer
is_power_of_2(), NAK.

> 
> Signed-off-by: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
> ---
>  drivers/bus/brcmstb_gisb.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/brcmstb_gisb.c b/drivers/bus/brcmstb_gisb.c
> index f364fa4..2816a04 100644
> --- a/drivers/bus/brcmstb_gisb.c
> +++ b/drivers/bus/brcmstb_gisb.c
> @@ -24,6 +24,7 @@
>  #include <linux/of.h>
>  #include <linux/bitops.h>
>  #include <linux/pm.h>
> +#include <linux/log2.h>
>  
>  #ifdef CONFIG_ARM
>  #include <asm/bug.h>
> @@ -171,7 +172,7 @@ brcmstb_gisb_master_to_str(struct brcmstb_gisb_arb_device *gdev,
>  {
>  	u32 mask = gdev->valid_mask & masters;
>  
> -	if (hweight_long(mask) != 1)
> +	if (!is_power_of_2(mask))
>  		return NULL;
>  
>  	return gdev->master_names[ffs(mask) - 1];
> 


-- 
Florian
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