diff options
| -rw-r--r-- | include/linux/hardirq.h | 6 | ||||
| -rw-r--r-- | include/linux/smp_lock.h | 14 | ||||
| -rw-r--r-- | kernel/Kconfig.preempt | 4 | ||||
| -rw-r--r-- | kernel/sched.c | 19 | ||||
| -rw-r--r-- | lib/kernel_lock.c | 123 |
5 files changed, 5 insertions, 161 deletions
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 8d302298a161..2961ec788046 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -72,11 +72,7 @@ #define in_softirq() (softirq_count()) #define in_interrupt() (irq_count()) -#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) -# define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != kernel_locked()) -#else -# define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0) -#endif +#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0) #ifdef CONFIG_PREEMPT # define PREEMPT_CHECK_OFFSET 1 diff --git a/include/linux/smp_lock.h b/include/linux/smp_lock.h index 58962c51dee1..aab3a4cff4e1 100644 --- a/include/linux/smp_lock.h +++ b/include/linux/smp_lock.h @@ -17,22 +17,10 @@ extern void __lockfunc __release_kernel_lock(void); __release_kernel_lock(); \ } while (0) -/* - * Non-SMP kernels will never block on the kernel lock, - * so we are better off returning a constant zero from - * reacquire_kernel_lock() so that the compiler can see - * it at compile-time. - */ -#if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_BKL) -# define return_value_on_smp return -#else -# define return_value_on_smp -#endif - static inline int reacquire_kernel_lock(struct task_struct *task) { if (unlikely(task->lock_depth >= 0)) - return_value_on_smp __reacquire_kernel_lock(); + return __reacquire_kernel_lock(); return 0; } diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt index 4420ef427f83..0669b70fa6a3 100644 --- a/kernel/Kconfig.preempt +++ b/kernel/Kconfig.preempt @@ -52,10 +52,6 @@ config PREEMPT endchoice -config PREEMPT_BKL - def_bool y - depends on SMP || PREEMPT - config RCU_TRACE bool "Enable tracing for RCU - currently stats in debugfs" select DEBUG_FS diff --git a/kernel/sched.c b/kernel/sched.c index 22712b2e058a..629614ad0358 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3955,10 +3955,9 @@ EXPORT_SYMBOL(schedule); asmlinkage void __sched preempt_schedule(void) { struct thread_info *ti = current_thread_info(); -#ifdef CONFIG_PREEMPT_BKL struct task_struct *task = current; int saved_lock_depth; -#endif + /* * If there is a non-zero preempt_count or interrupts are disabled, * we do not want to preempt the current task. Just return.. @@ -3974,14 +3973,10 @@ asmlinkage void __sched preempt_schedule(void) * clear ->lock_depth so that schedule() doesnt * auto-release the semaphore: */ -#ifdef CONFIG_PREEMPT_BKL saved_lock_depth = task->lock_depth; task->lock_depth = -1; -#endif schedule(); -#ifdef CONFIG_PREEMPT_BKL task->lock_depth = saved_lock_depth; -#endif sub_preempt_count(PREEMPT_ACTIVE); /* @@ -4002,10 +3997,9 @@ EXPORT_SYMBOL(preempt_schedule); asmlinkage void __sched preempt_schedule_irq(void) { struct thread_info *ti = current_thread_info(); -#ifdef CONFIG_PREEMPT_BKL struct task_struct *task = current; int saved_lock_depth; -#endif + /* Catch callers which need to be fixed */ BUG_ON(ti->preempt_count || !irqs_disabled()); @@ -4017,16 +4011,12 @@ asmlinkage void __sched preempt_schedule_irq(void) * clear ->lock_depth so that schedule() doesnt * auto-release the semaphore: */ -#ifdef CONFIG_PREEMPT_BKL saved_lock_depth = task->lock_depth; task->lock_depth = -1; -#endif local_irq_enable(); schedule(); local_irq_disable(); -#ifdef CONFIG_PREEMPT_BKL task->lock_depth = saved_lock_depth; -#endif sub_preempt_count(PREEMPT_ACTIVE); /* @@ -5241,11 +5231,8 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) spin_unlock_irqrestore(&rq->lock, flags); /* Set the preempt count _outside_ the spinlocks! */ -#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) - task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); -#else task_thread_info(idle)->preempt_count = 0; -#endif + /* * The idle tasks have their own, simple scheduling class: */ 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); |