From 8d155576011845121c995d70d4fe198d8b8e7330 Mon Sep 17 00:00:00 2001
From: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Date: Sun, 27 Mar 2022 13:20:28 +0800
Subject: gma500: fix an incorrect NULL check on list iterator
Git-commit: bdef417d84536715145f6dc9cc3275c46f26295a
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

The bug is here:
	return crtc;

The list iterator value 'crtc' will *always* be set and non-NULL by
list_for_each_entry(), so it is incorrect to assume that the iterator
value will be NULL if the list is empty or no element is found.

To fix the bug, return 'crtc' when found, otherwise return NULL.

Cc: stable@vger.kernel.org
fixes: 89c78134cc54d ("gma500: Add Poulsbo support")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220327052028.2013-1-xiam0nd.tong@gmail.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/gma500/psb_intel_display.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/gma500/psb_intel_display.c b/drivers/gpu/drm/gma500/psb_intel_display.c
index fb8234f4d128..dc467996cce4 100644
--- a/drivers/gpu/drm/gma500/psb_intel_display.c
+++ b/drivers/gpu/drm/gma500/psb_intel_display.c
@@ -524,14 +524,15 @@ void psb_intel_crtc_init(struct drm_device *dev, int pipe,
 
 struct drm_crtc *psb_intel_get_crtc_from_pipe(struct drm_device *dev, int pipe)
 {
-	struct drm_crtc *crtc = NULL;
+	struct drm_crtc *crtc;
 
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 		struct gma_crtc *gma_crtc = to_gma_crtc(crtc);
+
 		if (gma_crtc->pipe == pipe)
-			break;
+			return crtc;
 	}
-	return crtc;
+	return NULL;
 }
 
 int gma_connector_clones(struct drm_device *dev, int type_mask)
-- 
2.38.1