Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 10802d1..ac42ae4 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -7,7 +7,7 @@
    License.  See linux/COPYING for more information.
 
    Uniform CD-ROM driver for Linux.
-   See Documentation/cdrom/cdrom-standard.tex for usage information.
+   See Documentation/cdrom/cdrom-standard.rst for usage information.
 
    The routines in the file provide a uniform interface between the
    software that uses CD-ROMs and the various low-level drivers that
@@ -265,6 +265,7 @@
 /* #define ERRLOGMASK (CD_WARNING|CD_OPEN|CD_COUNT_TRACKS|CD_CLOSE) */
 /* #define ERRLOGMASK (CD_WARNING|CD_REG_UNREG|CD_DO_IOCTL|CD_OPEN|CD_CLOSE|CD_COUNT_TRACKS) */
 
+#include <linux/atomic.h>
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/major.h>
@@ -410,10 +411,10 @@
  * hack to have the capability flags defined const, while we can still
  * change it here without gcc complaining at every line.
  */
-#define ENSURE(call, bits)			\
-do {						\
-	if (cdo->call == NULL)			\
-		*change_capability &= ~(bits);	\
+#define ENSURE(cdo, call, bits)					\
+do {								\
+	if (cdo->call == NULL)					\
+		WARN_ON_ONCE((cdo)->capability & (bits));	\
 } while (0)
 
 /*
@@ -589,7 +590,6 @@
 {
 	static char banner_printed;
 	const struct cdrom_device_ops *cdo = cdi->ops;
-	int *change_capability = (int *)&cdo->capability; /* hack */
 
 	cd_dbg(CD_OPEN, "entering register_cdrom\n");
 
@@ -601,16 +601,16 @@
 		cdrom_sysctl_register();
 	}
 
-	ENSURE(drive_status, CDC_DRIVE_STATUS);
+	ENSURE(cdo, drive_status, CDC_DRIVE_STATUS);
 	if (cdo->check_events == NULL && cdo->media_changed == NULL)
-		*change_capability = ~(CDC_MEDIA_CHANGED | CDC_SELECT_DISC);
-	ENSURE(tray_move, CDC_CLOSE_TRAY | CDC_OPEN_TRAY);
-	ENSURE(lock_door, CDC_LOCK);
-	ENSURE(select_speed, CDC_SELECT_SPEED);
-	ENSURE(get_last_session, CDC_MULTI_SESSION);
-	ENSURE(get_mcn, CDC_MCN);
-	ENSURE(reset, CDC_RESET);
-	ENSURE(generic_packet, CDC_GENERIC_PACKET);
+		WARN_ON_ONCE(cdo->capability & (CDC_MEDIA_CHANGED | CDC_SELECT_DISC));
+	ENSURE(cdo, tray_move, CDC_CLOSE_TRAY | CDC_OPEN_TRAY);
+	ENSURE(cdo, lock_door, CDC_LOCK);
+	ENSURE(cdo, select_speed, CDC_SELECT_SPEED);
+	ENSURE(cdo, get_last_session, CDC_MULTI_SESSION);
+	ENSURE(cdo, get_mcn, CDC_MCN);
+	ENSURE(cdo, reset, CDC_RESET);
+	ENSURE(cdo, generic_packet, CDC_GENERIC_PACKET);
 	cdi->mc_flags = 0;
 	cdi->options = CDO_USE_FFLAGS;
 
@@ -3693,9 +3693,9 @@
 
 static void cdrom_sysctl_register(void)
 {
-	static int initialized;
+	static atomic_t initialized = ATOMIC_INIT(0);
 
-	if (initialized == 1)
+	if (!atomic_add_unless(&initialized, 1, 1))
 		return;
 
 	cdrom_sysctl_header = register_sysctl_table(cdrom_root_table);
@@ -3706,8 +3706,6 @@
 	cdrom_sysctl_settings.debug = debug;
 	cdrom_sysctl_settings.lock = lockdoor;
 	cdrom_sysctl_settings.check = check_media_type;
-
-	initialized = 1;
 }
 
 static void cdrom_sysctl_unregister(void)