diff mbox series

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

Message ID 20221123231400.614679-3-john.ogness@linutronix.de
State New
Headers
Series printk: cleanup buffer handling |

Commit Message

John Ogness Nov. 23, 2022, 11:13 p.m. UTC 
  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(-)

Comments

Petr Mladek Nov. 24, 2022, 11:14 a.m. UTC | #1 
On Thu 2022-11-24 00:19:55, John Ogness wrote:
> 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>

This is really useful.

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr
diff mbox series

Patch

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];