Re: [PATCH v2 07/28] ARM: mmu: Separate index and address in create_sections()

[Sam Ravnborg <sam@ravnborg.org>]

On Wed, May 16, 2018 at 01:00:15PM -0700, Andrey Smirnov wrote:
> Both TTB index and address used to fill that entry are derived from
> the same variable 'addr' which requires shifting right and left by 20
> and somewhat confusing.
> 
> Split the counter used to iterate over elements of  TTB into a
> separate variable to make this code a bit easier to read.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> ---
>  arch/arm/cpu/mmu.h | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/cpu/mmu.h b/arch/arm/cpu/mmu.h
> index 59f72049f..d71cd7e38 100644
> --- a/arch/arm/cpu/mmu.h
> +++ b/arch/arm/cpu/mmu.h
> @@ -1,6 +1,8 @@
>  #ifndef __ARM_MMU_H
>  #define __ARM_MMU_H
>  
> +#include <linux/sizes.h>
> +
>  #ifdef CONFIG_MMU
>  void __mmu_cache_on(void);
>  void __mmu_cache_off(void);
> @@ -28,8 +30,12 @@ static inline void
>  create_sections(uint32_t *ttb, unsigned long addr,
>  		int size_m, unsigned int flags)
>  {
> -	for (addr >>= 20; addr < size_m; addr++)
> -		ttb[addr] = (addr << 20) | flags;
> +	unsigned long ttb_start = addr >> 20;
> +	unsigned long ttb_end   = ttb_start + size_m;
> +	unsigned int i;
> +
> +	for (i = ttb_start; i < ttb_end; i++, addr += SZ_1M)
> +		ttb[i] = addr | flags;
>  }

Much more readable - thanks.
Of personal taste I would have put the assignment of addr inside the
for loop to IMO increase readability.

	Sam

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