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-rw-r--r--lib/kernel_lock.c136
1 files changed, 0 insertions, 136 deletions
diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c
deleted file mode 100644
index d80e1226586..00000000000
--- a/lib/kernel_lock.c
+++ /dev/null
@@ -1,136 +0,0 @@
-/*
- * lib/kernel_lock.c
- *
- * This is the traditional BKL - big kernel lock. Largely
- * relegated to obsolescence, but used by various less
- * important (or lazy) subsystems.
- */
-#include <linux/module.h>
-#include <linux/kallsyms.h>
-#include <linux/semaphore.h>
-#include <linux/smp_lock.h>
-
-/*
- * 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_RAW_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 - do_raw_spin_trylock will never
- * return false in that case)
- */
-int __lockfunc __reacquire_kernel_lock(void)
-{
- while (!do_raw_spin_trylock(&kernel_flag)) {
- if (need_resched())
- return -EAGAIN;
- cpu_relax();
- }
- preempt_disable();
- return 0;
-}
-
-void __lockfunc __release_kernel_lock(void)
-{
- do_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
- * do_raw_spin_trylock() will always succeed.
- */
-#ifdef CONFIG_PREEMPT
-static inline void __lock_kernel(void)
-{
- preempt_disable();
- if (unlikely(!do_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) {
- do_raw_spin_lock(&kernel_flag);
- return;
- }
-
- /*
- * Otherwise, let's wait for the kernel lock
- * with preemption enabled..
- */
- do {
- preempt_enable();
- while (raw_spin_is_locked(&kernel_flag))
- cpu_relax();
- preempt_disable();
- } while (!do_raw_spin_trylock(&kernel_flag));
- }
-}
-
-#else
-
-/*
- * Non-preemption case - just get the spinlock
- */
-static inline void __lock_kernel(void)
-{
- do_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):
- */
- do_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(const char *func, const char *file, int line)
-{
- int depth = current->lock_depth + 1;
-
- if (likely(!depth)) {
- might_sleep();
- __lock_kernel();
- }
- current->lock_depth = depth;
-}
-
-void __lockfunc _unlock_kernel(const char *func, const char *file, int line)
-{
- BUG_ON(current->lock_depth < 0);
- if (likely(--current->lock_depth < 0))
- __unlock_kernel();
-}
-
-EXPORT_SYMBOL(_lock_kernel);
-EXPORT_SYMBOL(_unlock_kernel);
-