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authorFrederic Weisbecker <fweisbec@gmail.com>2013-03-22 15:04:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-22 16:41:20 -0700
commitdc72c32e1fd872a9a4fdfe645283c9dcd68e556d (patch)
tree66f817ecb840f59173de2a95a9a69fb5c3a75d21 /kernel/printk.c
parentfe8d52614bd419cedef85ef55850fd090373f481 (diff)
downloadlinux-dc72c32e1fd872a9a4fdfe645283c9dcd68e556d.tar.gz
printk: Provide a wake_up_klogd() off-case
wake_up_klogd() is useless when CONFIG_PRINTK=n because neither printk() nor printk_sched() are in use and there are actually no waiter on log_wait waitqueue. It should be a stub in this case for users like bust_spinlocks(). Otherwise this results in this warning when CONFIG_PRINTK=n and CONFIG_IRQ_WORK=n: kernel/built-in.o In function `wake_up_klogd': (.text.wake_up_klogd+0xb4): undefined reference to `irq_work_queue' To fix this, provide an off-case for wake_up_klogd() when CONFIG_PRINTK=n. There is much more from console_unlock() and other console related code in printk.c that should be moved under CONFIG_PRINTK. But for now, focus on a minimal fix as we passed the merged window already. [akpm@linux-foundation.org: include printk.h in bust_spinlocks.c] Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reported-by: James Hogan <james.hogan@imgtec.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/printk.c')
-rw-r--r--kernel/printk.c80
1 files changed, 39 insertions, 41 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index 0b31715f335..abbdd9e2ac8 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -63,8 +63,6 @@ void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...)
#define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
#define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */
-DECLARE_WAIT_QUEUE_HEAD(log_wait);
-
int console_printk[4] = {
DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */
DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */
@@ -224,6 +222,7 @@ struct log {
static DEFINE_RAW_SPINLOCK(logbuf_lock);
#ifdef CONFIG_PRINTK
+DECLARE_WAIT_QUEUE_HEAD(log_wait);
/* the next printk record to read by syslog(READ) or /proc/kmsg */
static u64 syslog_seq;
static u32 syslog_idx;
@@ -1957,45 +1956,6 @@ int is_console_locked(void)
return console_locked;
}
-/*
- * Delayed printk version, for scheduler-internal messages:
- */
-#define PRINTK_BUF_SIZE 512
-
-#define PRINTK_PENDING_WAKEUP 0x01
-#define PRINTK_PENDING_SCHED 0x02
-
-static DEFINE_PER_CPU(int, printk_pending);
-static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
-
-static void wake_up_klogd_work_func(struct irq_work *irq_work)
-{
- int pending = __this_cpu_xchg(printk_pending, 0);
-
- if (pending & PRINTK_PENDING_SCHED) {
- char *buf = __get_cpu_var(printk_sched_buf);
- printk(KERN_WARNING "[sched_delayed] %s", buf);
- }
-
- if (pending & PRINTK_PENDING_WAKEUP)
- wake_up_interruptible(&log_wait);
-}
-
-static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
- .func = wake_up_klogd_work_func,
- .flags = IRQ_WORK_LAZY,
-};
-
-void wake_up_klogd(void)
-{
- preempt_disable();
- if (waitqueue_active(&log_wait)) {
- this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
- irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
- }
- preempt_enable();
-}
-
static void console_cont_flush(char *text, size_t size)
{
unsigned long flags;
@@ -2458,6 +2418,44 @@ static int __init printk_late_init(void)
late_initcall(printk_late_init);
#if defined CONFIG_PRINTK
+/*
+ * Delayed printk version, for scheduler-internal messages:
+ */
+#define PRINTK_BUF_SIZE 512
+
+#define PRINTK_PENDING_WAKEUP 0x01
+#define PRINTK_PENDING_SCHED 0x02
+
+static DEFINE_PER_CPU(int, printk_pending);
+static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
+
+static void wake_up_klogd_work_func(struct irq_work *irq_work)
+{
+ int pending = __this_cpu_xchg(printk_pending, 0);
+
+ if (pending & PRINTK_PENDING_SCHED) {
+ char *buf = __get_cpu_var(printk_sched_buf);
+ printk(KERN_WARNING "[sched_delayed] %s", buf);
+ }
+
+ if (pending & PRINTK_PENDING_WAKEUP)
+ wake_up_interruptible(&log_wait);
+}
+
+static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
+ .func = wake_up_klogd_work_func,
+ .flags = IRQ_WORK_LAZY,
+};
+
+void wake_up_klogd(void)
+{
+ preempt_disable();
+ if (waitqueue_active(&log_wait)) {
+ this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
+ irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
+ }
+ preempt_enable();
+}
int printk_sched(const char *fmt, ...)
{