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author | Ingo Molnar <mingo@elte.hu> | 2008-01-25 21:08:33 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-01-25 21:08:33 +0100 |
commit | 6478d8800b75253b2a934ddcb734e13ade023ad0 (patch) | |
tree | df4017269b8755735578445c0a8a9e8b3b2615e9 /lib/kernel_lock.c | |
parent | 58b8a73ab8becfcaea84abc2a06038281efa4c8a (diff) | |
download | linux-stable-6478d8800b75253b2a934ddcb734e13ade023ad0.tar.gz linux-stable-6478d8800b75253b2a934ddcb734e13ade023ad0.tar.bz2 linux-stable-6478d8800b75253b2a934ddcb734e13ade023ad0.zip |
sched: remove the !PREEMPT_BKL code
remove the !PREEMPT_BKL code.
this removes 160 lines of legacy code.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'lib/kernel_lock.c')
-rw-r--r-- | lib/kernel_lock.c | 123 |
1 files changed, 0 insertions, 123 deletions
diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c index f73e2f8c308f..812dbf00844b 100644 --- a/lib/kernel_lock.c +++ b/lib/kernel_lock.c @@ -9,7 +9,6 @@ #include <linux/module.h> #include <linux/kallsyms.h> -#ifdef CONFIG_PREEMPT_BKL /* * The 'big kernel semaphore' * @@ -86,128 +85,6 @@ void __lockfunc unlock_kernel(void) up(&kernel_sem); } -#else - -/* - * The 'big kernel lock' - * - * This spinlock 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. - * - * Don't use in new code. - */ -static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kernel_flag); - - -/* - * Acquire/release the underlying lock from the scheduler. - * - * This is called with preemption disabled, and should - * return an error value if it cannot get the lock and - * TIF_NEED_RESCHED gets set. - * - * If it successfully gets the lock, it should increment - * the preemption count like any spinlock does. - * - * (This works on UP too - _raw_spin_trylock will never - * return false in that case) - */ -int __lockfunc __reacquire_kernel_lock(void) -{ - while (!_raw_spin_trylock(&kernel_flag)) { - if (test_thread_flag(TIF_NEED_RESCHED)) - return -EAGAIN; - cpu_relax(); - } - preempt_disable(); - return 0; -} - -void __lockfunc __release_kernel_lock(void) -{ - _raw_spin_unlock(&kernel_flag); - preempt_enable_no_resched(); -} - -/* - * 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. - */ -#ifdef CONFIG_PREEMPT -static inline void __lock_kernel(void) -{ - preempt_disable(); - if (unlikely(!_raw_spin_trylock(&kernel_flag))) { - /* - * If preemption was disabled even before this - * was called, there's nothing we can be polite - * about - just spin. - */ - if (preempt_count() > 1) { - _raw_spin_lock(&kernel_flag); - return; - } - - /* - * Otherwise, let's wait for the kernel lock - * with preemption enabled.. - */ - do { - preempt_enable(); - while (spin_is_locked(&kernel_flag)) - cpu_relax(); - preempt_disable(); - } while (!_raw_spin_trylock(&kernel_flag)); - } -} - -#else - -/* - * Non-preemption case - just get the spinlock - */ -static inline void __lock_kernel(void) -{ - _raw_spin_lock(&kernel_flag); -} -#endif - -static inline void __unlock_kernel(void) -{ - /* - * the BKL is not covered by lockdep, so we open-code the - * unlocking sequence (and thus avoid the dep-chain ops): - */ - _raw_spin_unlock(&kernel_flag); - preempt_enable(); -} - -/* - * Getting the big kernel lock. - * - * This cannot happen asynchronously, so we only need to - * worry about other CPU's. - */ -void __lockfunc lock_kernel(void) -{ - int depth = current->lock_depth+1; - if (likely(!depth)) - __lock_kernel(); - current->lock_depth = depth; -} - -void __lockfunc unlock_kernel(void) -{ - BUG_ON(current->lock_depth < 0); - if (likely(--current->lock_depth < 0)) - __unlock_kernel(); -} - -#endif - EXPORT_SYMBOL(lock_kernel); EXPORT_SYMBOL(unlock_kernel); |