Re: [v9 2/2] misc: pci_endpoint_test: Fix overflow of bar_size

[Niklas Cassel <cassel@kernel.org>]

On Wed, Jan 08, 2025 at 03:25:04PM +0800, Hans Zhang wrote:
> With 8GB BAR2, running pcitest -b 2 fails with "TEST FAILED".
> 
> The return value of the `pci_resource_len` interface is not an integer.
> Using `pcitest` with an 8GB BAR2, the bar_size of integer type will
> overflow.
> 
> Change the data type of bar_size from integer to u64, to fix the above
> issue.
> 
> Signed-off-by: Hans Zhang <18255117159@163.com>
> ---
> Changes since v8:
> https://lore.kernel.org/linux-pci/20250104151652.1652181-1-18255117159@163.com/
> 
> - Split the patch.
> 
> Changes since v4-v7:
> https://lore.kernel.org/linux-pci/20250102120222.1403906-1-18255117159@163.com/
> 
> - Fix 32-bit OS warnings and errors.
> - Fix undefined reference to `__udivmoddi4`
> 
> Changes since v3:
> https://lore.kernel.org/linux-pci/20241221141009.27317-1-18255117159@163.com/
> 
> - The patch subject were modified.
> 
> Changes since v2:
> https://lore.kernel.org/linux-pci/20241220075253.16791-1-18255117159@163.com/
> 
> - Fix "changes" part goes below the --- line
> - The patch commit message were modified.
> 
> Changes since v1:
> https://lore.kernel.org/linux-pci/20241217121220.19676-1-18255117159@163.com/
> 
> - The patch subject and commit message were modified.
> ---
>  drivers/misc/pci_endpoint_test.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c
> index 0e68dfa7257a..812508308187 100644
> --- a/drivers/misc/pci_endpoint_test.c
> +++ b/drivers/misc/pci_endpoint_test.c
> @@ -280,10 +280,11 @@ static int pci_endpoint_test_bar_memcmp(struct pci_endpoint_test *test,
>  static bool pci_endpoint_test_bar(struct pci_endpoint_test *test,
>  				  enum pci_barno barno)
>  {
> -	int j, bar_size, buf_size, iters, remain;
> +	int j, buf_size, iters;
>  	void *write_buf __free(kfree) = NULL;
>  	void *read_buf __free(kfree) = NULL;
>  	struct pci_dev *pdev = test->pdev;
> +	u64 bar_size;
>  
>  	if (!test->bar[barno])
>  		return false;
> @@ -307,7 +308,8 @@ static bool pci_endpoint_test_bar(struct pci_endpoint_test *test,
>  	if (!read_buf)
>  		return false;
>  
> -	iters = bar_size / buf_size;
> +	do_div(bar_size, buf_size);
> +	iters = bar_size;
>  	for (j = 0; j < iters; j++)
>  		if (pci_endpoint_test_bar_memcmp(test, barno, buf_size * j,
>  						 write_buf, read_buf, buf_size))
> -- 
> 2.25.1
> 

Reviewed-by: Niklas Cassel <cassel@kernel.org>