printk: move size limit macros into internal.h

The size limit macros are located further down in printk.c and
behind ifdef conditionals. This complicates their usage for
upcoming changes. Move the macros into internal.h so that they
are still invisible outside of printk, but easily accessible
for printk.

Also, the maximum size of formatted extended messages does not
need to be known by any code outside of printk, so move it to
internal.h as well. And like CONSOLE_LOG_MAX, for !CONFIG_PRINTK
set CONSOLE_EXT_LOG_MAX to 0 to reduce the static memory
footprint.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230109100800.1085541-2-john.ogness@linutronix.de

Author: jogness

include/linux/printk.h

@@ -44,8 +44,6 @@ static inline const char *printk_skip_headers(const char *buffer)
 	return buffer;
 }
 
-#define CONSOLE_EXT_LOG_MAX	8192
-
 /* printk's without a loglevel use this.. */
 #define MESSAGE_LOGLEVEL_DEFAULT CONFIG_MESSAGE_LOGLEVEL_DEFAULT
 

kernel/printk/internal.h

@@ -14,6 +14,24 @@ int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write,
 
 #ifdef CONFIG_PRINTK
 
+#ifdef CONFIG_PRINTK_CALLER
+#define PREFIX_MAX		48
+#else
+#define PREFIX_MAX		32
+#endif
+
+/* the maximum size of a formatted record (i.e. with prefix added per line) */
+#define CONSOLE_LOG_MAX		1024
+
+/* the maximum size of a formatted extended record */
+#define CONSOLE_EXT_LOG_MAX	8192
+
+/* the maximum size for a dropped text message */
+#define DROPPED_TEXT_MAX	64
+
+/* the maximum size allowed to be reserved for a record */
+#define LOG_LINE_MAX		(CONSOLE_LOG_MAX - PREFIX_MAX)
+
 /* Flags for a single printk record. */
 enum printk_info_flags {
 	LOG_NEWLINE	= 2,	/* text ended with a newline */
@@ -48,6 +66,12 @@ u16 printk_parse_prefix(const char *text, int *level,
 			enum printk_info_flags *flags);
 #else
 
+#define PREFIX_MAX		0
+#define CONSOLE_LOG_MAX		0
+#define CONSOLE_EXT_LOG_MAX	0
+#define DROPPED_TEXT_MAX	0
+#define LOG_LINE_MAX		0
+
 /*
  * In !PRINTK builds we still export console_sem
  * semaphore and some of console functions (console_unlock()/etc.), so

kernel/printk/printk.c

@@ -465,21 +465,6 @@ static struct latched_seq clear_seq = {
 	.val[1]		= 0,
 };
 
-#ifdef CONFIG_PRINTK_CALLER
-#define PREFIX_MAX		48
-#else
-#define PREFIX_MAX		32
-#endif
-
-/* the maximum size of a formatted record (i.e. with prefix added per line) */
-#define CONSOLE_LOG_MAX		1024
-
-/* the maximum size for a dropped text message */
-#define DROPPED_TEXT_MAX	64
-
-/* the maximum size allowed to be reserved for a record */
-#define LOG_LINE_MAX		(CONSOLE_LOG_MAX - PREFIX_MAX)
-
 #define LOG_LEVEL(v)		((v) & 0x07)
 #define LOG_FACILITY(v)		((v) >> 3 & 0xff)
 
@@ -2387,8 +2372,6 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre
 
 #else /* CONFIG_PRINTK */
 
-#define CONSOLE_LOG_MAX		0
-#define DROPPED_TEXT_MAX	0
 #define printk_time		false
 
 #define prb_read_valid(rb, seq, r)	false