linux-kernel - [PATCH AUTOSEL 4.9 16/62] fbdev/core: Disable console-lock warnings when fb.lockless_register

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Date:   Sun, 2 Sep 2018 13:14:21 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Thomas Zimmermann <tzimmermann@...e.de>,
        Steven Rostedt <rostedt@...dmis.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.9 16/62] fbdev/core: Disable console-lock warnings
 when fb.lockless_register_fb is set

From: Thomas Zimmermann <tzimmermann@...e.de>

[ Upstream commit 3f2ce54284a60500eb6dca1dca6fd615df8f9aa3 ]

If the console is unlocked during registration, the console subsystem
generates significant amounts of warnings, which obfuscate actual
debugging messages. Setting ignore_console_lock_warning while debugging
console registration avoid the noise.

v3:
	- manipulate ignore_console_lock_warning with atomic_{inc,dec}
v2:
	- restore ignore_console_lock_warning if lock_fb_info() fails

Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
Acked-by: Hans de Goede <hdegoede@...hat.com>
Reviewed-by: Petr Mladek <pmladek@...e.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Cc: Steven Rostedt (VMware) <rostedt@...dmis.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/video/fbdev/core/fbmem.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 76c1ad96fb37..34e8744a52e0 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1682,17 +1682,22 @@ static int do_register_framebuffer(struct fb_info *fb_info)
 	event.info = fb_info;
 	if (!lockless_register_fb)
 		console_lock();
+	else
+		atomic_inc(&ignore_console_lock_warning);
 	if (!lock_fb_info(fb_info)) {
-		if (!lockless_register_fb)
-			console_unlock();
-		return -ENODEV;
+		ret = -ENODEV;
+		goto unlock_console;
 	}
+	ret = 0;
 
 	fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
 	unlock_fb_info(fb_info);
+unlock_console:
 	if (!lockless_register_fb)
 		console_unlock();
-	return 0;
+	else
+		atomic_dec(&ignore_console_lock_warning);
+	return ret;
 }
 
 static int do_unregister_framebuffer(struct fb_info *fb_info)
-- 
2.17.1