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From: John Ogness <john.ogness@linutronix.de>
Date: Tue, 12 Feb 2019 15:29:54 +0100
Subject: [PATCH 16/25] printk: implement CON_PRINTBUFFER
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.0/older/patches-5.0.10-rt7.tar.xz
If the CON_PRINTBUFFER flag is not set, do not replay the history
for that console.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/printk/printk.c | 25 ++++++-------------------
1 file changed, 6 insertions(+), 19 deletions(-)
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -399,10 +399,6 @@ static u32 log_first_idx;
static u64 log_next_seq;
static u32 log_next_idx;
-/* the next printk record to write to the console */
-static u64 console_seq;
-static u32 console_idx;
-
/* the next printk record to read after the last 'clear' command */
static u64 clear_seq;
static u32 clear_idx;
@@ -1596,8 +1592,12 @@ static void call_console_drivers(u64 seq
if (!(con->flags & CON_ENABLED))
continue;
if (!con->wrote_history) {
- printk_write_history(con, seq);
- continue;
+ if (con->flags & CON_PRINTBUFFER) {
+ printk_write_history(con, seq);
+ continue;
+ }
+ con->wrote_history = 1;
+ con->printk_seq = seq - 1;
}
if (!con->write)
continue;
@@ -1822,8 +1822,6 @@ EXPORT_SYMBOL(printk);
static u64 syslog_seq;
static u32 syslog_idx;
-static u64 console_seq;
-static u32 console_idx;
static u64 log_first_seq;
static u32 log_first_idx;
static u64 log_next_seq;
@@ -2224,7 +2222,6 @@ early_param("keep_bootcon", keep_bootcon
void register_console(struct console *newcon)
{
int i;
- unsigned long flags;
struct console *bcon = NULL;
struct console_cmdline *c;
static bool has_preferred;
@@ -2340,16 +2337,6 @@ void register_console(struct console *ne
if (newcon->flags & CON_EXTENDED)
nr_ext_console_drivers++;
- if (newcon->flags & CON_PRINTBUFFER) {
- /*
- * console_unlock(); will print out the buffered messages
- * for us.
- */
- logbuf_lock_irqsave(flags);
- console_seq = syslog_seq;
- console_idx = syslog_idx;
- logbuf_unlock_irqrestore(flags);
- }
console_unlock();
console_sysfs_notify();
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