X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2Fkernel_lock.c;h=01a3c22c1b5a9c951dc33a0c37179306f36e18e4;hb=b8f6ec2e61f650fd1a316a207a00965bcb8805d4;hp=e0fdfddb406ec3975673f150f46bd3302bc08599;hpb=912b2539e1e062cec73e2e61448e507f7719bd08;p=linux-2.6-omap-h63xx.git diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c index e0fdfddb406..01a3c22c1b5 100644 --- a/lib/kernel_lock.c +++ b/lib/kernel_lock.c @@ -2,91 +2,13 @@ * lib/kernel_lock.c * * This is the traditional BKL - big kernel lock. Largely - * relegated to obsolescense, but used by various less + * relegated to obsolescence, but used by various less * important (or lazy) subsystems. */ #include #include #include - -#ifdef CONFIG_PREEMPT_BKL -/* - * The 'big kernel semaphore' - * - * This mutex is taken and released recursively by lock_kernel() - * and unlock_kernel(). It is transparently dropped and reacquired - * over schedule(). It is used to protect legacy code that hasn't - * been migrated to a proper locking design yet. - * - * Note: code locked by this semaphore will only be serialized against - * other code using the same locking facility. The code guarantees that - * the task remains on the same CPU. - * - * Don't use in new code. - */ -static DECLARE_MUTEX(kernel_sem); - -/* - * Re-acquire the kernel semaphore. - * - * This function is called with preemption off. - * - * We are executing in schedule() so the code must be extremely careful - * about recursion, both due to the down() and due to the enabling of - * preemption. schedule() will re-check the preemption flag after - * reacquiring the semaphore. - */ -int __lockfunc __reacquire_kernel_lock(void) -{ - struct task_struct *task = current; - int saved_lock_depth = task->lock_depth; - - BUG_ON(saved_lock_depth < 0); - - task->lock_depth = -1; - preempt_enable_no_resched(); - - down(&kernel_sem); - - preempt_disable(); - task->lock_depth = saved_lock_depth; - - return 0; -} - -void __lockfunc __release_kernel_lock(void) -{ - up(&kernel_sem); -} - -/* - * Getting the big kernel semaphore. - */ -void __lockfunc lock_kernel(void) -{ - struct task_struct *task = current; - int depth = task->lock_depth + 1; - - if (likely(!depth)) - /* - * No recursion worries - we set up lock_depth _after_ - */ - down(&kernel_sem); - - task->lock_depth = depth; -} - -void __lockfunc unlock_kernel(void) -{ - struct task_struct *task = current; - - BUG_ON(task->lock_depth < 0); - - if (likely(--task->lock_depth < 0)) - up(&kernel_sem); -} - -#else +#include /* * The 'big kernel lock' @@ -132,7 +54,7 @@ void __lockfunc __release_kernel_lock(void) } /* - * These are the BKL spinlocks - we try to be polite about preemption. + * These are the BKL spinlocks - we try to be polite about preemption. * If SMP is not on (ie UP preemption), this all goes away because the * _raw_spin_trylock() will always succeed. */ @@ -206,8 +128,6 @@ void __lockfunc unlock_kernel(void) __unlock_kernel(); } -#endif - EXPORT_SYMBOL(lock_kernel); EXPORT_SYMBOL(unlock_kernel);