Re: FAILED: patch "[PATCH] iommu/io-pgtable-arm: Ensure we free the final level on" failed to apply to 4.4-stable tree

[Will Deacon <will.deacon@arm.com>]

Hi Greg,

On Tue, Jan 26, 2016 at 10:48:23PM -0800, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 4.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

Do you have the conflict handy? It applies to 4.4 here, so I guess its
somehow conflicting with another -stable patch, but I couldn't spot it.

Will

> ------------------ original commit in Linus's tree ------------------
> 
> From 12c2ab09571e8aae3a87da2a4a452632a5fac1e5 Mon Sep 17 00:00:00 2001
> From: Will Deacon <will.deacon@arm.com>
> Date: Tue, 15 Dec 2015 16:08:12 +0000
> Subject: [PATCH] iommu/io-pgtable-arm: Ensure we free the final level on
>  teardown
> 
> When tearing down page tables, we return early for the final level
> since we know that we won't have any table pointers to follow.
> Unfortunately, this also means that we forget to free the final level,
> so we end up leaking memory.
> 
> Fix the issue by always freeing the current level, but just don't bother
> to iterate over the ptes if we're at the final level.
> 
> Cc: <stable@vger.kernel.org>
> Reported-by: Zhang Bo <zhangbo_a@xiaomi.com>
> Signed-off-by: Will Deacon <will.deacon@arm.com>
> 
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index 937ba23e48d7..8bbcbfe7695c 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -404,17 +404,18 @@ static void __arm_lpae_free_pgtable(struct arm_lpae_io_pgtable *data, int lvl,
>  	arm_lpae_iopte *start, *end;
>  	unsigned long table_size;
>  
> -	/* Only leaf entries at the last level */
> -	if (lvl == ARM_LPAE_MAX_LEVELS - 1)
> -		return;
> -
>  	if (lvl == ARM_LPAE_START_LVL(data))
>  		table_size = data->pgd_size;
>  	else
>  		table_size = ARM_LPAE_GRANULE(data);
>  
>  	start = ptep;
> -	end = (void *)ptep + table_size;
> +
> +	/* Only leaf entries at the last level */
> +	if (lvl == ARM_LPAE_MAX_LEVELS - 1)
> +		end = ptep;
> +	else
> +		end = (void *)ptep + table_size;
>  
>  	while (ptep != end) {
>  		arm_lpae_iopte pte = *ptep++;
>