[PATCH printk v2 2/7] console: Use BIT() macros for @flags values

John Ogness
2022-11-23T23:14:25Z

From: Thomas Gleixner <tglx@linutronix.de>

Rather than manually calculating powers of 2, use the BIT() macros.
Also take this opportunatity to cleanup and restructure the value
comments into proper kerneldoc comments.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
---
include/linux/console.h | 46 ++++++++++++++++++++++++++++++++---------
1 file changed, 36 insertions(+), 10 deletions(-)

diff --git a/include/linux/console.h b/include/linux/console.h
index 799fc3216aad..f7a14ea6bae0 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -15,6 +15,7 @@
#define _LINUX_CONSOLE_H_ 1

#include <linux/atomic.h>
+#include <linux/bits.h>
#include <linux/rculist.h>
#include <linux/types.h>

@@ -139,18 +140,43 @@ static inline int con_debug_leave(void)
/*
* The interface for a console, or any other device that wants to capture
* console messages (printer driver?)
- *
- * If a console driver is marked CON_BOOT then it will be auto-unregistered
- * when the first real console is registered. This is for early-printk drivers.
*/

-#define CON_PRINTBUFFER (1)
-#define CON_CONSDEV (2) /* Preferred console, /dev/console */
-#define CON_ENABLED (4)
-#define CON_BOOT (8)
-#define CON_ANYTIME (16) /* Safe to call when cpu is offline */
-#define CON_BRL (32) /* Used for a braille device */
-#define CON_EXTENDED (64) /* Use the extended output format a la /dev/kmsg */
+/**
+ * cons_flags - General console flags
+ * @CON_PRINTBUFFER: Used by newly registered consoles to avoid duplicate
+ * output of messages that were already shown by boot
+ * consoles or read by userspace via syslog() syscall.
+ * @CON_CONSDEV: Indicates that the console driver is backing
+ * /dev/console.
+ * @CON_ENABLED: Indicates if a console is allowed to print records. If
+ * false, the console also will not advance to later
+ * records.
+ * @CON_BOOT: Marks the console driver as early console driver which
+ * is used during boot before the real driver becomes
+ * available. It will be automatically unregistered
+ * when the real console driver is registered unless
+ * "keep_bootcon" parameter is used.
+ * @CON_ANYTIME: A misnomed historical flag which tells the core code
+ * that the legacy @console::write callback can be invoked
+ * on a CPU which is marked OFFLINE. That is misleading as
+ * it suggests that there is no contextual limit for
+ * invoking the callback. The original motivation was
+ * readiness of the per-CPU areas.
+ * @CON_BRL: Indicates a braille device which is exempt from
+ * receiving the printk spam for obvious reasons.
+ * @CON_EXTENDED: The console supports the extended output format of
+ * /dev/kmesg which requires a larger output buffer.
+ */
+enum cons_flags {
+ CON_PRINTBUFFER = BIT(0),
+ CON_CONSDEV = BIT(1),
+ CON_ENABLED = BIT(2),
+ CON_BOOT = BIT(3),
+ CON_ANYTIME = BIT(4),
+ CON_BRL = BIT(5),
+ CON_EXTENDED = BIT(6),
+};

struct console {
char name[16];
--
2.30.2