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From 4278945ff4909a5208c24ddb04ce28f61dcbb67f Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 17 Jul 2011 22:43:07 +0200
Subject: [PATCH 212/274] console-make-rt-friendly.patch
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/printk.c | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)
diff --git a/kernel/printk.c b/kernel/printk.c
index 9a27a94..28baa36 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -507,6 +507,7 @@ static void __call_console_drivers(unsigned start, unsigned end)
{
struct console *con;
+ migrate_disable();
for_each_console(con) {
if (exclusive_console && con != exclusive_console)
continue;
@@ -515,6 +516,7 @@ static void __call_console_drivers(unsigned start, unsigned end)
(con->flags & CON_ANYTIME)))
con->write(con, &LOG_BUF(start), end - start);
}
+ migrate_enable();
}
#ifdef CONFIG_EARLY_PRINTK
@@ -839,12 +841,18 @@ static inline int can_use_console(unsigned int cpu)
* interrupts disabled. It should return with 'lockbuf_lock'
* released but interrupts still disabled.
*/
-static int console_trylock_for_printk(unsigned int cpu)
+static int console_trylock_for_printk(unsigned int cpu, unsigned long flags)
__releases(&logbuf_lock)
{
int retval = 0, wake = 0;
+#ifdef CONFIG_PREEMPT_RT_FULL
+ int lock = !early_boot_irqs_disabled && !irqs_disabled_flags(flags) &&
+ !preempt_count();
+#else
+ int lock = 1;
+#endif
- if (console_trylock()) {
+ if (lock && console_trylock()) {
retval = 1;
/*
@@ -1021,8 +1029,15 @@ asmlinkage int vprintk(const char *fmt, va_list args)
* will release 'logbuf_lock' regardless of whether it
* actually gets the semaphore or not.
*/
- if (console_trylock_for_printk(this_cpu))
+ if (console_trylock_for_printk(this_cpu, flags)) {
+#ifndef CONFIG_PREEMPT_RT_FULL
console_unlock();
+#else
+ raw_local_irq_restore(flags);
+ console_unlock();
+ raw_local_irq_save(flags);
+#endif
+ }
lockdep_on();
out_restore_irqs:
@@ -1345,11 +1360,16 @@ again:
_con_start = con_start;
_log_end = log_end;
con_start = log_end; /* Flush */
+#ifndef CONFIG_PREEMPT_RT_FULL
raw_spin_unlock(&logbuf_lock);
stop_critical_timings(); /* don't trace print latency */
call_console_drivers(_con_start, _log_end);
start_critical_timings();
local_irq_restore(flags);
+#else
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+ call_console_drivers(_con_start, _log_end);
+#endif
}
console_locked = 0;
--
1.7.10.4
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