From 6478d8800b75253b2a934ddcb734e13ade023ad0 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 25 Jan 2008 21:08:33 +0100
Subject: 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>
---
lib/kernel_lock.c | 123 ------------------------------------------------------
1 file changed, 123 deletions(-)
(limited to 'lib')
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);
--
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