Messages in this thread Patch in this message | | | From | John Ogness <> | Subject | [PATCH printk v1 12/13] printk: remove @console_locked | Date | Mon, 7 Feb 2022 20:49:22 +0106 |
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The static global variable @console_locked is used to help debug VT code to make sure that certain code paths are running with the console_lock held. However, this information is also available with the static global variable @consoles_paused (for locking via console_lock()), and the static global variable @console_lock_count (for locking via console_trylock()).
Remove @console_locked and update is_console_locked() to use the alternative variables.
Signed-off-by: John Ogness <john.ogness@linutronix.de> --- kernel/printk/printk.c | 30 ++++++++++++++---------------- 1 file changed, 14 insertions(+), 16 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 135fbe647092..086155578f10 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -307,15 +307,7 @@ static void __pause_all_consoles(bool do_pause) #define pause_all_consoles() __pause_all_consoles(true) #define unpause_all_consoles() __pause_all_consoles(false) -/* - * This is used for debugging the mess that is the VT code by - * keeping track if we have the console semaphore held. It's - * definitely not the perfect debug tool (we don't know if _WE_ - * hold it and are racing, but it helps tracking those weird code - * paths in the console code where we end up in places I want - * locked without the console semaphore held). - */ -static int console_locked, console_suspended; +static int console_suspended; /* * Array of consoles built from command line options (console=) @@ -2595,7 +2587,6 @@ void console_lock(void) if (console_suspended) return; pause_all_consoles(); - console_locked = 1; console_may_schedule = 1; } EXPORT_SYMBOL(console_lock); @@ -2620,7 +2611,6 @@ int console_trylock(void) up_console_sem(); return 0; } - console_locked = 1; console_may_schedule = 0; return 1; } @@ -2647,14 +2637,25 @@ static int console_trylock_sched(bool may_schedule) return 0; } pause_all_consoles(); - console_locked = 1; console_may_schedule = 1; return 1; } +/* + * This is used to help to make sure that certain paths within the VT code are + * running with the console lock held. It is definitely not the perfect debug + * tool (it is not known if the VT code is the task holding the console lock), + * but it helps tracking those weird code paths in the console code such as + * when the console is suspended: where the console is not locked but no + * console printing may occur. + * + * Note: This returns true when the console is suspended but is not locked. + * This is intentional because the VT code must consider that situation + * the same as if the console was locked. + */ int is_console_locked(void) { - return (console_locked || atomic_read(&console_lock_count)); + return (consoles_paused || atomic_read(&console_lock_count)); } EXPORT_SYMBOL(is_console_locked); @@ -2687,8 +2688,6 @@ static inline bool console_is_usable(struct console *con) static void __console_unlock(void) { - console_locked = 0; - /* * Depending on whether console_lock() or console_trylock() was used, * appropriately allow the kthread printers to continue. @@ -2966,7 +2965,6 @@ void console_unblank(void) console_lock(); } - console_locked = 1; console_may_schedule = 0; for_each_console(c) if ((c->flags & CON_ENABLED) && c->unblank) -- 2.30.2
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