console: rename acquire/release_console_sem() to console_lock/unlock()
The -rt patches change the console_semaphore to console_mutex. As a
result, a quite large chunk of the patches changes all
acquire/release_console_sem() to acquire/release_console_mutex()
This commit makes things use more neutral function names which dont make
implications about the underlying lock.
The only real change is the return value of console_trylock which is
inverted from try_acquire_console_sem()
This patch also paves the way to switching console_sem from a semaphore to
a mutex.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: make console_trylock return 1 on success, per Geert]
Signed-off-by: Torben Hohn <torbenh@gmx.de>
Cc: Thomas Gleixner <tglx@tglx.de>
Cc: Greg KH <gregkh@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/printk.c b/kernel/printk.c
index 53d9a9e..2ddbdc7 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -97,7 +97,7 @@
/*
* logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars
* It is also used in interesting ways to provide interlocking in
- * release_console_sem().
+ * console_unlock();.
*/
static DEFINE_SPINLOCK(logbuf_lock);
@@ -501,7 +501,7 @@
/*
* Call the console drivers, asking them to write out
* log_buf[start] to log_buf[end - 1].
- * The console_sem must be held.
+ * The console_lock must be held.
*/
static void call_console_drivers(unsigned start, unsigned end)
{
@@ -604,11 +604,11 @@
*
* This is printk(). It can be called from any context. We want it to work.
*
- * We try to grab the console_sem. If we succeed, it's easy - we log the output and
+ * We try to grab the console_lock. If we succeed, it's easy - we log the output and
* call the console drivers. If we fail to get the semaphore we place the output
* into the log buffer and return. The current holder of the console_sem will
- * notice the new output in release_console_sem() and will send it to the
- * consoles before releasing the semaphore.
+ * notice the new output in console_unlock(); and will send it to the
+ * consoles before releasing the lock.
*
* One effect of this deferred printing is that code which calls printk() and
* then changes console_loglevel may break. This is because console_loglevel
@@ -659,19 +659,19 @@
/*
* Try to get console ownership to actually show the kernel
* messages from a 'printk'. Return true (and with the
- * console_semaphore held, and 'console_locked' set) if it
+ * console_lock held, and 'console_locked' set) if it
* is successful, false otherwise.
*
* This gets called with the 'logbuf_lock' spinlock held and
* interrupts disabled. It should return with 'lockbuf_lock'
* released but interrupts still disabled.
*/
-static int acquire_console_semaphore_for_printk(unsigned int cpu)
+static int console_trylock_for_printk(unsigned int cpu)
__releases(&logbuf_lock)
{
int retval = 0;
- if (!try_acquire_console_sem()) {
+ if (console_trylock()) {
retval = 1;
/*
@@ -827,12 +827,12 @@
* actual magic (print out buffers, wake up klogd,
* etc).
*
- * The acquire_console_semaphore_for_printk() function
+ * The console_trylock_for_printk() function
* will release 'logbuf_lock' regardless of whether it
* actually gets the semaphore or not.
*/
- if (acquire_console_semaphore_for_printk(this_cpu))
- release_console_sem();
+ if (console_trylock_for_printk(this_cpu))
+ console_unlock();
lockdep_on();
out_restore_irqs:
@@ -993,7 +993,7 @@
if (!console_suspend_enabled)
return;
printk("Suspending console(s) (use no_console_suspend to debug)\n");
- acquire_console_sem();
+ console_lock();
console_suspended = 1;
up(&console_sem);
}
@@ -1004,7 +1004,7 @@
return;
down(&console_sem);
console_suspended = 0;
- release_console_sem();
+ console_unlock();
}
/**
@@ -1027,21 +1027,21 @@
case CPU_DYING:
case CPU_DOWN_FAILED:
case CPU_UP_CANCELED:
- acquire_console_sem();
- release_console_sem();
+ console_lock();
+ console_unlock();
}
return NOTIFY_OK;
}
/**
- * acquire_console_sem - lock the console system for exclusive use.
+ * console_lock - lock the console system for exclusive use.
*
- * Acquires a semaphore which guarantees that the caller has
+ * Acquires a lock which guarantees that the caller has
* exclusive access to the console system and the console_drivers list.
*
* Can sleep, returns nothing.
*/
-void acquire_console_sem(void)
+void console_lock(void)
{
BUG_ON(in_interrupt());
down(&console_sem);
@@ -1050,21 +1050,29 @@
console_locked = 1;
console_may_schedule = 1;
}
-EXPORT_SYMBOL(acquire_console_sem);
+EXPORT_SYMBOL(console_lock);
-int try_acquire_console_sem(void)
+/**
+ * console_trylock - try to lock the console system for exclusive use.
+ *
+ * Tried to acquire a lock which guarantees that the caller has
+ * exclusive access to the console system and the console_drivers list.
+ *
+ * returns 1 on success, and 0 on failure to acquire the lock.
+ */
+int console_trylock(void)
{
if (down_trylock(&console_sem))
- return -1;
+ return 0;
if (console_suspended) {
up(&console_sem);
- return -1;
+ return 0;
}
console_locked = 1;
console_may_schedule = 0;
- return 0;
+ return 1;
}
-EXPORT_SYMBOL(try_acquire_console_sem);
+EXPORT_SYMBOL(console_trylock);
int is_console_locked(void)
{
@@ -1095,20 +1103,20 @@
}
/**
- * release_console_sem - unlock the console system
+ * console_unlock - unlock the console system
*
- * Releases the semaphore which the caller holds on the console system
+ * Releases the console_lock which the caller holds on the console system
* and the console driver list.
*
- * While the semaphore was held, console output may have been buffered
- * by printk(). If this is the case, release_console_sem() emits
- * the output prior to releasing the semaphore.
+ * While the console_lock was held, console output may have been buffered
+ * by printk(). If this is the case, console_unlock(); emits
+ * the output prior to releasing the lock.
*
* If there is output waiting for klogd, we wake it up.
*
- * release_console_sem() may be called from any context.
+ * console_unlock(); may be called from any context.
*/
-void release_console_sem(void)
+void console_unlock(void)
{
unsigned long flags;
unsigned _con_start, _log_end;
@@ -1141,7 +1149,7 @@
if (wake_klogd)
wake_up_klogd();
}
-EXPORT_SYMBOL(release_console_sem);
+EXPORT_SYMBOL(console_unlock);
/**
* console_conditional_schedule - yield the CPU if required
@@ -1150,7 +1158,7 @@
* if this CPU should yield the CPU to another task, do
* so here.
*
- * Must be called within acquire_console_sem().
+ * Must be called within console_lock();.
*/
void __sched console_conditional_schedule(void)
{
@@ -1171,14 +1179,14 @@
if (down_trylock(&console_sem) != 0)
return;
} else
- acquire_console_sem();
+ console_lock();
console_locked = 1;
console_may_schedule = 0;
for_each_console(c)
if ((c->flags & CON_ENABLED) && c->unblank)
c->unblank();
- release_console_sem();
+ console_unlock();
}
/*
@@ -1189,7 +1197,7 @@
struct console *c;
struct tty_driver *driver = NULL;
- acquire_console_sem();
+ console_lock();
for_each_console(c) {
if (!c->device)
continue;
@@ -1197,7 +1205,7 @@
if (driver)
break;
}
- release_console_sem();
+ console_unlock();
return driver;
}
@@ -1208,17 +1216,17 @@
*/
void console_stop(struct console *console)
{
- acquire_console_sem();
+ console_lock();
console->flags &= ~CON_ENABLED;
- release_console_sem();
+ console_unlock();
}
EXPORT_SYMBOL(console_stop);
void console_start(struct console *console)
{
- acquire_console_sem();
+ console_lock();
console->flags |= CON_ENABLED;
- release_console_sem();
+ console_unlock();
}
EXPORT_SYMBOL(console_start);
@@ -1340,7 +1348,7 @@
* Put this console in the list - keep the
* preferred driver at the head of the list.
*/
- acquire_console_sem();
+ console_lock();
if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) {
newcon->next = console_drivers;
console_drivers = newcon;
@@ -1352,14 +1360,14 @@
}
if (newcon->flags & CON_PRINTBUFFER) {
/*
- * release_console_sem() will print out the buffered messages
+ * console_unlock(); will print out the buffered messages
* for us.
*/
spin_lock_irqsave(&logbuf_lock, flags);
con_start = log_start;
spin_unlock_irqrestore(&logbuf_lock, flags);
}
- release_console_sem();
+ console_unlock();
console_sysfs_notify();
/*
@@ -1396,7 +1404,7 @@
return braille_unregister_console(console);
#endif
- acquire_console_sem();
+ console_lock();
if (console_drivers == console) {
console_drivers=console->next;
res = 0;
@@ -1418,7 +1426,7 @@
if (console_drivers != NULL && console->flags & CON_CONSDEV)
console_drivers->flags |= CON_CONSDEV;
- release_console_sem();
+ console_unlock();
console_sysfs_notify();
return res;
}
