linux-kernel - Re: [PATCH] arm:pm: Use kmemdup to replace duplicating its implementation

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Date:   Mon, 13 Aug 2018 15:28:33 +0300
From:   Vladimir Zapolskiy <vz@...ia.com>
To:     zhong jiang <zhongjiang@...wei.com>
Cc:     linux@...linux.org.uk, slemieux.tyco@...il.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm:pm: Use kmemdup to replace duplicating its
 implementation

Hi zhong jiang,

On 08/10/2018 05:40 AM, zhong jiang wrote:
> kmemdup is better than kmalloc() + memcpy(), and we do not like
> open code. So just use kmemdup instead.
> 
> Signed-off-by: zhong jiang <zhongjiang@...wei.com>
> ---
>  arch/arm/mach-lpc32xx/pm.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/mach-lpc32xx/pm.c b/arch/arm/mach-lpc32xx/pm.c
> index 6247157..6eefff8 100644
> --- a/arch/arm/mach-lpc32xx/pm.c
> +++ b/arch/arm/mach-lpc32xx/pm.c
> @@ -86,7 +86,8 @@ static int lpc32xx_pm_enter(suspend_state_t state)
>  	void *iram_swap_area;
>  
>  	/* Allocate some space for temporary IRAM storage */
> -	iram_swap_area = kmalloc(lpc32xx_sys_suspend_sz, GFP_KERNEL);
> +	iram_swap_area = kmemdup((void *)TEMP_IRAM_AREA,
> +				lpc32xx_sys_suspend_sz, GFP_KERNEL);

there is a minor coding style issue, which is reported by checkpatch:

CHECK: Alignment should match open parenthesis
#53: FILE: arch/arm/mach-lpc32xx/pm.c:90:

Other than that the change is valid, I'll fix the indentation issue
myself and apply the change for v4.19.

--
Best wishes,
Vladimir

>  	if (!iram_swap_area) {
>  		printk(KERN_ERR
>  		       "PM Suspend: cannot allocate memory to save portion "
> @@ -94,10 +95,6 @@ static int lpc32xx_pm_enter(suspend_state_t state)
>  		return -ENOMEM;
>  	}
>  
> -	/* Backup a small area of IRAM used for the suspend code */
> -	memcpy(iram_swap_area, (void *) TEMP_IRAM_AREA,
> -		lpc32xx_sys_suspend_sz);
> -
>  	/*
>  	 * Copy code to suspend system into IRAM. The suspend code
>  	 * needs to run from IRAM as DRAM may no longer be available
>