linux-kernel - Re: [PATCH] drm/fb-helper: Add missed unlocks in setcmap

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Message-ID: <e6ebb634-4cb5-34d4-c661-4cebbe2fdbf1@axentia.se>
Date:   Thu, 3 Dec 2020 17:11:28 +0100
From:   Peter Rosin <peda@...ntia.se>
To:     Chuhong Yuan <hslester96@...il.com>
Cc:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/fb-helper: Add missed unlocks in setcmap_legacy()

Hi!

On 2020-12-03 15:42, Chuhong Yuan wrote:
> setcmap_legacy() does not call drm_modeset_unlock_all() in some exits,
> add the missed unlocks with goto to fix it.
> 
> Fixes: 964c60063bff ("drm/fb-helper: separate the fb_setcmap helper into atomic and legacy paths")
> Signed-off-by: Chuhong Yuan <hslester96@...il.com>

Yup, my patch fumbled the locking. Sorry, and thanks for cleaning up my mess!

Acked-by: Peter Rosin <peda@...ntia.se>

(Spelled that as Ached-by at first, what does that mean??)

Cheers,
Peter

> ---
>  drivers/gpu/drm/drm_fb_helper.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 1543d9d10970..8033467db4be 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -923,11 +923,15 @@ static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
>  	drm_modeset_lock_all(fb_helper->dev);
>  	drm_client_for_each_modeset(modeset, &fb_helper->client) {
>  		crtc = modeset->crtc;
> -		if (!crtc->funcs->gamma_set || !crtc->gamma_size)
> -			return -EINVAL;
> +		if (!crtc->funcs->gamma_set || !crtc->gamma_size) {
> +			ret = -EINVAL;
> +			goto out;
> +		}
>  
> -		if (cmap->start + cmap->len > crtc->gamma_size)
> -			return -EINVAL;
> +		if (cmap->start + cmap->len > crtc->gamma_size) {
> +			ret = -EINVAL;
> +			goto out;
> +		}
>  
>  		r = crtc->gamma_store;
>  		g = r + crtc->gamma_size;
> @@ -940,8 +944,9 @@ static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
>  		ret = crtc->funcs->gamma_set(crtc, r, g, b,
>  					     crtc->gamma_size, NULL);
>  		if (ret)
> -			return ret;
> +			goto out;
>  	}
> +out:
>  	drm_modeset_unlock_all(fb_helper->dev);
>  
>  	return ret;
>