linux-kernel - Re: [PATCH] media: i2c: adv748x: Fix unsafe macros

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Message-ID: <22780ef3-514e-d013-1da8-9576780fde1c@ideasonboard.com>
Date:   Tue, 22 Oct 2019 15:11:20 +0100
From:   Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Dmitry Vyukov <dvyukov@...gle.com>
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: i2c: adv748x: Fix unsafe macros

Hi Gustavo,

On 22/10/2019 14:25, Gustavo A. R. Silva wrote:
> Enclose multiple macro parameters in parentheses in order to
> make such macros safer and fix the Clang warning below:
> 
> drivers/media/i2c/adv748x/adv748x-afe.c:452:12: warning: operator '?:'
> has lower precedence than '|'; '|' will be evaluated first
> [-Wbitwise-conditional-parentheses]
> 
> ret = sdp_clrset(state, ADV748X_SDP_FRP, ADV748X_SDP_FRP_MASK, enable
> ? ctrl->val - 1 : 0);
> 
> Fixes: 3e89586a64df ("media: i2c: adv748x: add adv748x driver")
> Reported-by: Dmitry Vyukov <dvyukov@...gle.com>
> Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>

Thanks,

You beat me to posting - but that looks incredibly close (identical I
think) to the one I had prepared.

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>

> ---
>  drivers/media/i2c/adv748x/adv748x.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/i2c/adv748x/adv748x.h b/drivers/media/i2c/adv748x/adv748x.h
> index 5042f9e94aee..fccb388ce179 100644
> --- a/drivers/media/i2c/adv748x/adv748x.h
> +++ b/drivers/media/i2c/adv748x/adv748x.h
> @@ -394,10 +394,10 @@ int adv748x_write_block(struct adv748x_state *state, int client_page,
>  
>  #define io_read(s, r) adv748x_read(s, ADV748X_PAGE_IO, r)
>  #define io_write(s, r, v) adv748x_write(s, ADV748X_PAGE_IO, r, v)
> -#define io_clrset(s, r, m, v) io_write(s, r, (io_read(s, r) & ~m) | v)
> +#define io_clrset(s, r, m, v) io_write(s, r, (io_read(s, r) & ~(m)) | (v))
>  
>  #define hdmi_read(s, r) adv748x_read(s, ADV748X_PAGE_HDMI, r)
> -#define hdmi_read16(s, r, m) (((hdmi_read(s, r) << 8) | hdmi_read(s, r+1)) & m)
> +#define hdmi_read16(s, r, m) (((hdmi_read(s, r) << 8) | hdmi_read(s, (r)+1)) & (m))
>  #define hdmi_write(s, r, v) adv748x_write(s, ADV748X_PAGE_HDMI, r, v)
>  
>  #define repeater_read(s, r) adv748x_read(s, ADV748X_PAGE_REPEATER, r)
> @@ -405,11 +405,11 @@ int adv748x_write_block(struct adv748x_state *state, int client_page,
>  
>  #define sdp_read(s, r) adv748x_read(s, ADV748X_PAGE_SDP, r)
>  #define sdp_write(s, r, v) adv748x_write(s, ADV748X_PAGE_SDP, r, v)
> -#define sdp_clrset(s, r, m, v) sdp_write(s, r, (sdp_read(s, r) & ~m) | v)
> +#define sdp_clrset(s, r, m, v) sdp_write(s, r, (sdp_read(s, r) & ~(m)) | (v))
>  
>  #define cp_read(s, r) adv748x_read(s, ADV748X_PAGE_CP, r)
>  #define cp_write(s, r, v) adv748x_write(s, ADV748X_PAGE_CP, r, v)
> -#define cp_clrset(s, r, m, v) cp_write(s, r, (cp_read(s, r) & ~m) | v)
> +#define cp_clrset(s, r, m, v) cp_write(s, r, (cp_read(s, r) & ~(m)) | (v))
>  
>  #define tx_read(t, r) adv748x_read(t->state, t->page, r)
>  #define tx_write(t, r, v) adv748x_write(t->state, t->page, r, v)
>