linux-kernel - Re: [PATCH v2] drm,fbdev: td043mtea1: Convert sprintf() family to sysfs

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Message-ID: <9907040c-7e25-4aa5-a4be-6f4820e335f1@linaro.org>
Date: Tue, 19 Mar 2024 09:07:10 +0100
From: Neil Armstrong <neil.armstrong@...aro.org>
To: Li Zhijian <lizhijian@...itsu.com>, linux-kernel@...r.kernel.org
Cc: Jessica Zhang <quic_jesszhan@...cinc.com>, Sam Ravnborg
 <sam@...nborg.org>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
 Helge Deller <deller@....de>, linux-omap@...r.kernel.org,
 linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v2] drm,fbdev: td043mtea1: Convert sprintf() family to
 sysfs_emit() family

Hi,

On 19/03/2024 04:55, Li Zhijian wrote:
> Per filesystems/sysfs.rst, show() should only use sysfs_emit()
> or sysfs_emit_at() when formatting the value to be returned to user space.
> 
> coccinelle complains that there are still a couple of functions that use
> snprintf(). Convert them to sysfs_emit().
> 
> sprintf() and scnprintf() will be converted as well if they have.
> 
> Generally, this patch is generated by
> make coccicheck M=<path/to/file> MODE=patch \
> COCCI=scripts/coccinelle/api/device_attr_show.cocci
> 
> No functional change intended

Please split patches in 2, while the driver targets the same hw, they
are not under the same subsystems.

Neil

> 
> CC: Neil Armstrong <neil.armstrong@...aro.org>
> CC: Jessica Zhang <quic_jesszhan@...cinc.com>
> CC: Sam Ravnborg <sam@...nborg.org>
> CC: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
> CC: Maxime Ripard <mripard@...nel.org>
> CC: Thomas Zimmermann <tzimmermann@...e.de>
> CC: David Airlie <airlied@...il.com>
> CC: Daniel Vetter <daniel@...ll.ch>
> CC: Helge Deller <deller@....de>
> CC: linux-omap@...r.kernel.org
> CC: linux-fbdev@...r.kernel.org
> CC: dri-devel@...ts.freedesktop.org
> Signed-off-by: Li Zhijian <lizhijian@...itsu.com>
> ---
> V2:
>     Fix missing '+' before '=' in drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
> 
> This is a part of the work "Fix coccicheck device_attr_show warnings"[1]
> Split them per subsystem so that the maintainer can review it easily
> [1] https://lore.kernel.org/lkml/20240116041129.3937800-1-lizhijian@fujitsu.com/
> ---
>   drivers/gpu/drm/panel/panel-tpo-td043mtea1.c        | 13 ++++---------
>   .../omap2/omapfb/displays/panel-tpo-td043mtea1.c    | 12 ++++--------
>   2 files changed, 8 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panel/panel-tpo-td043mtea1.c b/drivers/gpu/drm/panel/panel-tpo-td043mtea1.c
> index cf4609bb9b1d..0983fe47eb5a 100644
> --- a/drivers/gpu/drm/panel/panel-tpo-td043mtea1.c
> +++ b/drivers/gpu/drm/panel/panel-tpo-td043mtea1.c
> @@ -242,16 +242,11 @@ static ssize_t gamma_show(struct device *dev, struct device_attribute *attr,
>   	struct td043mtea1_panel *lcd = dev_get_drvdata(dev);
>   	ssize_t len = 0;
>   	unsigned int i;
> -	int ret;
>   
> -	for (i = 0; i < ARRAY_SIZE(lcd->gamma); i++) {
> -		ret = snprintf(buf + len, PAGE_SIZE - len, "%u ",
> -			       lcd->gamma[i]);
> -		if (ret < 0)
> -			return ret;
> -		len += ret;
> -	}
> -	buf[len - 1] = '\n';
> +	for (i = 0; i < ARRAY_SIZE(lcd->gamma); i++)
> +		len += sysfs_emit_at(buf, len, "%u ", lcd->gamma[i]);
> +	if (len)
> +		buf[len - 1] = '\n';
>   
>   	return len;
>   }
> diff --git a/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c b/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
> index 477789cff8e0..3624452e1dd0 100644
> --- a/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
> +++ b/drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td043mtea1.c
> @@ -228,14 +228,10 @@ static ssize_t tpo_td043_gamma_show(struct device *dev,
>   	int ret;
>   	int i;
>   
> -	for (i = 0; i < ARRAY_SIZE(ddata->gamma); i++) {
> -		ret = snprintf(buf + len, PAGE_SIZE - len, "%u ",
> -				ddata->gamma[i]);
> -		if (ret < 0)
> -			return ret;
> -		len += ret;
> -	}
> -	buf[len - 1] = '\n';
> +	for (i = 0; i < ARRAY_SIZE(ddata->gamma); i++)
> +		len += sysfs_emit_at(buf, len, "%u ", ddata->gamma[i]);
> +	if (len)
> +		buf[len - 1] = '\n';
>   
>   	return len;
>   }