boot_delay should only affect output

The boot_delay parameter affects all printk(), even if the log level
prevents visible output from the call. It results in delays greater than the user intended without purpose.

This patch changes the behaviour of boot_delay to only delay output.

Signed-off-by Andrew Cooks <[email protected]>

---
 kernel/printk.c |   40 +++++++++++++++++++++-------------------
 1 files changed, 21 insertions(+), 19 deletions(-)

kernel/printk.c +21 -19

index 66a2ea3..c098003 100644
@@ -741,6 +741,21 @@ void __init setup_log_buf(int early)
 		free, (free * 100) / __LOG_BUF_LEN);
 }
 
+static bool __read_mostly ignore_loglevel;
+
+static int __init ignore_loglevel_setup(char *str)
+{
+	ignore_loglevel = 1;
+	printk(KERN_INFO "debug: ignoring loglevel setting.\n");
+
+	return 0;
+}
+
+early_param("ignore_loglevel", ignore_loglevel_setup);
+module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
+	"print all kernel messages to the console.");
+
 #ifdef CONFIG_BOOT_PRINTK_DELAY
 
 static int boot_delay; /* msecs delay after each printk during bootup */

@@ -764,13 +779,15 @@ static int __init boot_delay_setup(char *str)
 }
 __setup("boot_delay=", boot_delay_setup);
 
-static void boot_delay_msec(void)
+static void boot_delay_msec(int level)
 {
 	unsigned long long k;
 	unsigned long timeout;
 
-	if (boot_delay == 0 || system_state != SYSTEM_BOOTING)
+	if ((boot_delay == 0 || system_state != SYSTEM_BOOTING)
+		|| (level >= console_loglevel && !ignore_loglevel)) {
 		return;
+	}
 
 	k = (unsigned long long)loops_per_msec * boot_delay;
 

@@ -789,7 +806,7 @@ static void boot_delay_msec(void)
 	}
 }
 #else
-static inline void boot_delay_msec(void)
+static inline void boot_delay_msec(int level)
 {
 }
 #endif

@@ -1232,21 +1249,6 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
 	return do_syslog(type, buf, len, SYSLOG_FROM_CALL);
 }
 
-static bool __read_mostly ignore_loglevel;
-
-static int __init ignore_loglevel_setup(char *str)
-{
-	ignore_loglevel = 1;
-	printk(KERN_INFO "debug: ignoring loglevel setting.\n");
-
-	return 0;
-}
-
-early_param("ignore_loglevel", ignore_loglevel_setup);
-module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
-	"print all kernel messages to the console.");
-
 /*
  * Call the console drivers, asking them to write out
  * log_buf[start] to log_buf[end - 1].

@@ -1492,7 +1494,7 @@ asmlinkage int vprintk_emit(int facility, int level,
 	int this_cpu;
 	int printed_len = 0;
 
-	boot_delay_msec();
+	boot_delay_msec(level);
 	printk_delay();
 
 	/* This stops the holder of console_sem just where we want him */

Quoted 5 lines · Andrew Cooks

The boot_delay parameter affects all printk(), even if the log level
prevents visible output from the call. It results in delays greater than the user intended without purpose.

This patch changes the behaviour of boot_delay to only delay output.

Seems sensible.

Couldn't that be done for printk_delay too?