Re: [PATCH v2 1/1] of: unittest: fix warning on PowerPC frame size warning

From: Frank Rowand <frowand.list@gmail.com>
To: Jim Quinlan <jim2101024@gmail.com>,
	Christoph Hellwig <hch@lst.de>,
	bcm-kernel-feedback-list@broadcom.com,
	james.quinlan@broadcom.com, Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE" 
	<devicetree@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/1] of: unittest: fix warning on PowerPC frame size warning
Date: Sun, 12 Dec 2021 16:47:24 -0600	[thread overview]
Message-ID: <598c9bcd-a956-07f1-17a2-5177a8bd5458@gmail.com> (raw)
In-Reply-To: <20211210184636.7273-2-jim2101024@gmail.com>

moved the file's maintainers from the "cc:" list to the "to:" list

review comments below

On 12/10/21 1:46 PM, Jim Quinlan wrote:
> The struct device variable "dev_bogus" was triggering this warning
> on a PowerPC build:
> 
>     drivers/of/unittest.c: In function 'of_unittest_dma_ranges_one.constprop':
>     [...] >> The frame size of 1424 bytes is larger than 1024 bytes
>              [-Wframe-larger-than=]
> 
> This variable is now dynamically allocated.

A side effect of the change is that dev_bogus is initialized to all
zeros instead of containing random data from the stack.

> 
> Fixes: e0d072782c734 ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
> ---
>  drivers/of/unittest.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
> index 481ba8682ebf..02c5cd06ad19 100644
> --- a/drivers/of/unittest.c
> +++ b/drivers/of/unittest.c
> @@ -911,11 +911,18 @@ static void __init of_unittest_dma_ranges_one(const char *path,
>  	if (!rc) {
>  		phys_addr_t	paddr;
>  		dma_addr_t	dma_addr;
> -		struct device	dev_bogus;
> +		struct device	*dev_bogus;
>  
> -		dev_bogus.dma_range_map = map;
> -		paddr = dma_to_phys(&dev_bogus, expect_dma_addr);
> -		dma_addr = phys_to_dma(&dev_bogus, expect_paddr);
> +		dev_bogus = kzalloc(sizeof(struct device), GFP_KERNEL);
> +		if (!dev_bogus) {
> +			unittest(0, "kzalloc() failed\n");
> +			kfree(map);
> +			return;
> +		}
> +
> +		dev_bogus->dma_range_map = map;
> +		paddr = dma_to_phys(dev_bogus, expect_dma_addr);
> +		dma_addr = phys_to_dma(dev_bogus, expect_paddr);
>  
>  		unittest(paddr == expect_paddr,
>  			 "of_dma_get_range: wrong phys addr %pap (expecting %llx) on node %pOF\n",
> @@ -925,6 +932,7 @@ static void __init of_unittest_dma_ranges_one(const char *path,
>  			 &dma_addr, expect_dma_addr, np);
>  
>  		kfree(map);
> +		kfree(dev_bogus);
>  	}
>  	of_node_put(np);
>  #endif
> 

Reviewed-by: Frank Rowand <frank.rowand@sony.com>