From: Russell King <rmk@arm.linux.org.uk>
[This patch series has also been separately sent to the architecture
maintainers]
Add console_device() to return the console tty driver structure and the
index. Acquire the console lock while scanning the list of console drivers
to protect us against console driver list manipulations.
Signed-off-by: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/char/tty_io.c | 9 ++-------
25-akpm/include/linux/console.h | 1 +
25-akpm/kernel/printk.c | 17 +++++++++++++++++
3 files changed, 20 insertions(+), 7 deletions(-)
diff -puN drivers/char/tty_io.c~provide-console_device drivers/char/tty_io.c
--- 25/drivers/char/tty_io.c~provide-console_device 2004-06-27 22:19:51.771209008 -0700
+++ 25-akpm/drivers/char/tty_io.c 2004-06-27 22:19:51.781207488 -0700
@@ -1355,13 +1355,8 @@ retry_open:
}
#endif
if (device == MKDEV(TTYAUX_MAJOR,1)) {
- struct console *c = console_drivers;
- for (c = console_drivers; c; c = c->next) {
- if (!c->device)
- continue;
- driver = c->device(c, &index);
- if (!driver)
- continue;
+ driver = console_device(&index);
+ if (driver) {
/* Don't let /dev/console block */
filp->f_flags |= O_NONBLOCK;
noctty = 1;
diff -puN include/linux/console.h~provide-console_device include/linux/console.h
--- 25/include/linux/console.h~provide-console_device 2004-06-27 22:19:51.773208704 -0700
+++ 25-akpm/include/linux/console.h 2004-06-27 22:20:18.212189368 -0700
@@ -104,6 +104,7 @@ extern void acquire_console_sem(void);
extern void release_console_sem(void);
extern void console_conditional_schedule(void);
extern void console_unblank(void);
+extern struct tty_driver *console_device(int *);
extern int is_console_locked(void);
/* Some debug stub to catch some of the obvious races in the VT code */
diff -puN kernel/printk.c~provide-console_device kernel/printk.c
--- 25/kernel/printk.c~provide-console_device 2004-06-27 22:19:51.776208248 -0700
+++ 25-akpm/kernel/printk.c 2004-06-27 22:24:02.218135288 -0700
@@ -683,6 +683,23 @@ void console_unblank(void)
}
EXPORT_SYMBOL(console_unblank);
+struct tty_driver *console_device(int *index)
+{
+ struct console *c;
+ struct tty_driver *driver = NULL;
+
+ acquire_console_sem();
+ for (c = console_drivers; c != NULL; c = c->next) {
+ if (!c->device)
+ continue;
+ driver = c->device(c, index);
+ if (driver)
+ break;
+ }
+ release_console_sem();
+ return driver;
+}
+
/*
* The console driver calls this routine during kernel initialization
* to register the console printing procedure with printk() and to
_