diff options
| -rw-r--r-- | kernel/printk/printk.c | 46 |
1 files changed, 32 insertions, 14 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 6e1b21a8a497..5ba37f813723 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -91,6 +91,29 @@ static struct lockdep_map console_lock_dep_map = { #endif /* + * Helper macros to handle lockdep when locking/unlocking console_sem. We use + * macros instead of functions so that _RET_IP_ contains useful information. + */ +#define down_console_sem() do { \ + down(&console_sem);\ + mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);\ +} while (0) + +static int __down_trylock_console_sem(unsigned long ip) +{ + if (down_trylock(&console_sem)) + return 1; + mutex_acquire(&console_lock_dep_map, 0, 1, ip); + return 0; +} +#define down_trylock_console_sem() __down_trylock_console_sem(_RET_IP_) + +#define up_console_sem() do { \ + mutex_release(&console_lock_dep_map, 1, _RET_IP_);\ + up(&console_sem);\ +} while (0) + +/* * 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_ @@ -1422,7 +1445,7 @@ static int console_trylock_for_printk(unsigned int cpu) */ if (!can_use_console(cpu)) { console_locked = 0; - up(&console_sem); + up_console_sem(); return 0; } return 1; @@ -1951,16 +1974,14 @@ void suspend_console(void) printk("Suspending console(s) (use no_console_suspend to debug)\n"); console_lock(); console_suspended = 1; - up(&console_sem); - mutex_release(&console_lock_dep_map, 1, _RET_IP_); + up_console_sem(); } void resume_console(void) { if (!console_suspend_enabled) return; - down(&console_sem); - mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_); + down_console_sem(); console_suspended = 0; console_unlock(); } @@ -2002,12 +2023,11 @@ void console_lock(void) { might_sleep(); - down(&console_sem); + down_console_sem(); if (console_suspended) return; console_locked = 1; console_may_schedule = 1; - mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_); } EXPORT_SYMBOL(console_lock); @@ -2021,15 +2041,14 @@ EXPORT_SYMBOL(console_lock); */ int console_trylock(void) { - if (down_trylock(&console_sem)) + if (down_trylock_console_sem()) return 0; if (console_suspended) { - up(&console_sem); + up_console_sem(); return 0; } console_locked = 1; console_may_schedule = 0; - mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_); return 1; } EXPORT_SYMBOL(console_trylock); @@ -2091,7 +2110,7 @@ void console_unlock(void) bool retry; if (console_suspended) { - up(&console_sem); + up_console_sem(); return; } @@ -2153,7 +2172,6 @@ skip: local_irq_restore(flags); } console_locked = 0; - mutex_release(&console_lock_dep_map, 1, _RET_IP_); /* Release the exclusive_console once it is used */ if (unlikely(exclusive_console)) @@ -2161,7 +2179,7 @@ skip: raw_spin_unlock(&logbuf_lock); - up(&console_sem); + up_console_sem(); /* * Someone could have filled up the buffer again, so re-check if there's @@ -2206,7 +2224,7 @@ void console_unblank(void) * oops_in_progress is set to 1.. */ if (oops_in_progress) { - if (down_trylock(&console_sem) != 0) + if (down_trylock_console_sem() != 0) return; } else console_lock(); |