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-rw-r--r--include/linux/hardirq.h6
-rw-r--r--include/linux/smp_lock.h14
-rw-r--r--kernel/Kconfig.preempt4
-rw-r--r--kernel/sched.c19
-rw-r--r--lib/kernel_lock.c123
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);