linux-kernel - [PATCH 5.4 058/168] media: rc: compile rc-cec.c into rc-core

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Date:   Mon, 15 Mar 2021 14:54:50 +0100
From:   gregkh@...uxfoundation.org
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hans Verkuil <hverkuil-cisco@...all.nl>,
        Hans de Goede <hdegoede@...hat.com>,
        Sean Young <sean@...s.org>,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Subject: [PATCH 5.4 058/168] media: rc: compile rc-cec.c into rc-core

From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

From: Hans Verkuil <hverkuil@...all.nl>

commit f09f9f93afad770a04b35235a0aa465fcc8d6e3d upstream.

The rc-cec keymap is unusual in that it can't be built as a module,
instead it is registered directly in rc-main.c if CONFIG_MEDIA_CEC_RC
is set. This is because it can be called from drm_dp_cec_set_edid() via
cec_register_adapter() in an asynchronous context, and it is not
allowed to use request_module() to load rc-cec.ko in that case. Trying to
do so results in a 'WARN_ON_ONCE(wait && current_is_async())'.

Since this keymap is only used if CONFIG_MEDIA_CEC_RC is set, we
just compile this keymap into the rc-core module and never as a
separate module.

Signed-off-by: Hans Verkuil <hverkuil-cisco@...all.nl>
Fixes: 2c6d1fffa1d9 (drm: add support for DisplayPort CEC-Tunneling-over-AUX)
Reported-by: Hans de Goede <hdegoede@...hat.com>
Signed-off-by: Sean Young <sean@...s.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/media/rc/Makefile         |    1 +
 drivers/media/rc/keymaps/Makefile |    1 -
 drivers/media/rc/keymaps/rc-cec.c |   28 +++++++++++-----------------
 drivers/media/rc/rc-main.c        |    6 ++++++
 include/media/rc-map.h            |    7 +++++++
 5 files changed, 25 insertions(+), 18 deletions(-)

--- a/drivers/media/rc/Makefile
+++ b/drivers/media/rc/Makefile
@@ -5,6 +5,7 @@ obj-y += keymaps/
 obj-$(CONFIG_RC_CORE) += rc-core.o
 rc-core-y := rc-main.o rc-ir-raw.o
 rc-core-$(CONFIG_LIRC) += lirc_dev.o
+rc-core-$(CONFIG_MEDIA_CEC_RC) += keymaps/rc-cec.o
 rc-core-$(CONFIG_BPF_LIRC_MODE2) += bpf-lirc.o
 obj-$(CONFIG_IR_NEC_DECODER) += ir-nec-decoder.o
 obj-$(CONFIG_IR_RC5_DECODER) += ir-rc5-decoder.o
--- a/drivers/media/rc/keymaps/Makefile
+++ b/drivers/media/rc/keymaps/Makefile
@@ -20,7 +20,6 @@ obj-$(CONFIG_RC_MAP) += rc-adstech-dvb-t
 			rc-behold.o \
 			rc-behold-columbus.o \
 			rc-budget-ci-old.o \
-			rc-cec.o \
 			rc-cinergy-1400.o \
 			rc-cinergy.o \
 			rc-d680-dmb.o \
--- a/drivers/media/rc/keymaps/rc-cec.c
+++ b/drivers/media/rc/keymaps/rc-cec.c
@@ -1,6 +1,16 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /* Keytable for the CEC remote control
  *
+ * This keymap is unusual in that it can't be built as a module,
+ * instead it is registered directly in rc-main.c if CONFIG_MEDIA_CEC_RC
+ * is set. This is because it can be called from drm_dp_cec_set_edid() via
+ * cec_register_adapter() in an asynchronous context, and it is not
+ * allowed to use request_module() to load rc-cec.ko in that case.
+ *
+ * Since this keymap is only used if CONFIG_MEDIA_CEC_RC is set, we
+ * just compile this keymap into the rc-core module and never as a
+ * separate module.
+ *
  * Copyright (c) 2015 by Kamil Debski
  */
 
@@ -152,7 +162,7 @@ static struct rc_map_table cec[] = {
 	/* 0x77-0xff: Reserved */
 };
 
-static struct rc_map_list cec_map = {
+struct rc_map_list cec_map = {
 	.map = {
 		.scan		= cec,
 		.size		= ARRAY_SIZE(cec),
@@ -160,19 +170,3 @@ static struct rc_map_list cec_map = {
 		.name		= RC_MAP_CEC,
 	}
 };
-
-static int __init init_rc_map_cec(void)
-{
-	return rc_map_register(&cec_map);
-}
-
-static void __exit exit_rc_map_cec(void)
-{
-	rc_map_unregister(&cec_map);
-}
-
-module_init(init_rc_map_cec);
-module_exit(exit_rc_map_cec);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Kamil Debski");
--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -2033,6 +2033,9 @@ static int __init rc_core_init(void)
 
 	led_trigger_register_simple("rc-feedback", &led_feedback);
 	rc_map_register(&empty_map);
+#ifdef CONFIG_MEDIA_CEC_RC
+	rc_map_register(&cec_map);
+#endif
 
 	return 0;
 }
@@ -2042,6 +2045,9 @@ static void __exit rc_core_exit(void)
 	lirc_dev_exit();
 	class_unregister(&rc_class);
 	led_trigger_unregister_simple(led_feedback);
+#ifdef CONFIG_MEDIA_CEC_RC
+	rc_map_unregister(&cec_map);
+#endif
 	rc_map_unregister(&empty_map);
 }
 
--- a/include/media/rc-map.h
+++ b/include/media/rc-map.h
@@ -126,6 +126,13 @@ struct rc_map_list {
 	struct rc_map map;
 };
 
+#ifdef CONFIG_MEDIA_CEC_RC
+/*
+ * rc_map_list from rc-cec.c
+ */
+extern struct rc_map_list cec_map;
+#endif
+
 /* Routines from rc-map.c */
 
 /**