linux-kernel - Re: [PATCH] tree wide: Use kvfree() than conditional kfree()/vfree()

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Message-ID: <20151109160726.GB8644@n2100.arm.linux.org.uk>
Date:	Mon, 9 Nov 2015 16:07:26 +0000
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Cc:	akpm@...ux-foundation.org, linux-mm@...ck.org,
	linux-acpi@...r.kernel.org, drbd-user@...ts.linbit.com,
	linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	Oleg Drokin <oleg.drokin@...el.com>,
	Andreas Dilger <andreas.dilger@...el.com>,
	codalist@...a.cs.cmu.edu, linux-mtd@...ts.infradead.org,
	Jan Kara <jack@...e.com>, linux-fsdevel@...r.kernel.org,
	netdev@...r.kernel.org
Subject: Re: [PATCH] tree wide: Use kvfree() than conditional kfree()/vfree()

On Mon, Nov 09, 2015 at 08:56:10PM +0900, Tetsuo Handa wrote:
> There are many locations that do
> 
>   if (memory_was_allocated_by_vmalloc)
>     vfree(ptr);
>   else
>     kfree(ptr);
> 
> but kvfree() can handle both kmalloc()ed memory and vmalloc()ed memory
> using is_vmalloc_addr(). Unless callers have special reasons, we can
> replace this branch with kvfree(). Please check and reply if you found
> problems.
> 
> Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
> Acked-by: Michal Hocko <mhocko@...e.com>
> Cc: Russell King <linux@....linux.org.uk> # arm

Acked-by: Russell King <rmk+kernel@....linux.org.uk>

In so far as this ARM specific change looks reasonable.  Thanks.

> diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
> index e62400e..492bf3e 100644
> --- a/arch/arm/mm/dma-mapping.c
> +++ b/arch/arm/mm/dma-mapping.c
> @@ -1200,10 +1200,7 @@ error:
>  	while (i--)
>  		if (pages[i])
>  			__free_pages(pages[i], 0);
> -	if (array_size <= PAGE_SIZE)
> -		kfree(pages);
> -	else
> -		vfree(pages);
> +	kvfree(pages);
>  	return NULL;
>  }
>  
> @@ -1211,7 +1208,6 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages,
>  			       size_t size, struct dma_attrs *attrs)
>  {
>  	int count = size >> PAGE_SHIFT;
> -	int array_size = count * sizeof(struct page *);
>  	int i;
>  
>  	if (dma_get_attr(DMA_ATTR_FORCE_CONTIGUOUS, attrs)) {
> @@ -1222,10 +1218,7 @@ static int __iommu_free_buffer(struct device *dev, struct page **pages,
>  				__free_pages(pages[i], 0);
>  	}
>  
> -	if (array_size <= PAGE_SIZE)
> -		kfree(pages);
> -	else
> -		vfree(pages);
> +	kvfree(pages);
>  	return 0;
>  }
>  

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