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Date:   Thu, 3 Aug 2023 21:00:35 +0800
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Subject: Re: [PATCH v6 01/38] minmax: Add in_range() macro
To:     "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-arch@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
References: <20230802151406.3735276-1-willy@infradead.org>
 <20230802151406.3735276-2-willy@infradead.org>
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From:   Phi Nguyen <phind.uet@gmail.com>
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On 8/2/2023 11:13 PM, Matthew Wilcox (Oracle) wrote:
> diff --git a/include/linux/minmax.h b/include/linux/minmax.h
> index 798c6963909f..83aebc244cba 100644
> --- a/include/linux/minmax.h
> +++ b/include/linux/minmax.h
> @@ -3,6 +3,7 @@
>   #define _LINUX_MINMAX_H
>   
>   #include <linux/const.h>
> +#include <linux/types.h>
>   
>   /*
>    * min()/max()/clamp() macros must accomplish three things:
> @@ -222,6 +223,32 @@
>    */
>   #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
>   
> +static inline bool in_range64(u64 val, u64 start, u64 len)
> +{
> +	return (val - start) < len;
> +}
> +
> +static inline bool in_range32(u32 val, u32 start, u32 len)
> +{
> +	return (val - start) < len;
> +}
> +

I think these two functions return wrong result if val is smaller than 
start and len is big enough.