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Date: Fri, 26 Apr 2024 11:46:45 +0200
From: Johan Hovold <johan@kernel.org>
To: Krishna Kurapati <quic_kriskura@quicinc.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Thinh Nguyen <Thinh.Nguyen@synopsys.com>, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org, quic_ppratap@quicinc.com,
	quic_jackp@quicinc.com, kernel test robot <lkp@intel.com>
Subject: Re: [PATCH] usb: dwc3: core: Fix compile warning on s390 gcc in
 dwc3_get_phy call
Message-ID: <Zit4BfDgDpZDEVxp@hovoldconsulting.com>
References: <20240426050512.57384-1-quic_kriskura@quicinc.com>
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In-Reply-To: <20240426050512.57384-1-quic_kriskura@quicinc.com>

On Fri, Apr 26, 2024 at 10:35:12AM +0530, Krishna Kurapati wrote:
> Recent commit introduced support for reading Multiport PHYs and
> while doing so iterated over an integer variable which runs from
> [0-254] in the worst case scenario. But S390 compiler treats it as a
> warning and complains that the integer write to string can go to 11
> characters. Fix this by modifying iterator variable to u8.
> 
> Suggested-by: Johan Hovold <johan@kernel.org>
> Fixes: 30a46746ca5a ("usb: dwc3: core: Refactor PHY logic to support Multiport Controller")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202404241215.Mib19Cu7-lkp@intel.com/
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> ---
>  drivers/usb/dwc3/core.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 4dc6fc79c6d9..719305ab86c0 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1449,7 +1449,7 @@ static int dwc3_core_get_phy(struct dwc3 *dwc)
>  	struct device_node	*node = dev->of_node;
>  	char phy_name[9];
>  	int ret;
> -	int i;
> +	u8 i;

Perhaps unsigned int would have been better, but this should work too
(the broken compiler did get the upper bound right).

I assume you did not install a cross-compiler and tried to reproduce the
bogus warning?

In any case, if we want to suppress that bogus W=1 warning, this looks
good to me:

Reviewed-by: Johan Hovold <johan+linaro@kernel.org>

Johan