nfsd: move fsid_type choice out of fh_compose

[safe/jmp/linux-2.6] / lib / kernel_lock.c

diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c
index e713e86..39f1029 100644 (file)
--- a/lib/kernel_lock.c
+++ b/lib/kernel_lock.c
@@ -2,91 +2,13 @@
  * lib/kernel_lock.c
  *
  * This is the traditional BKL - big kernel lock. Largely
- * relegated to obsolescense, but used by various less
+ * relegated to obsolescence, but used by various less
  * important (or lazy) subsystems.
  */
 #include <linux/smp_lock.h>
 #include <linux/module.h>
 #include <linux/kallsyms.h>
-
-#ifdef CONFIG_PREEMPT_BKL
-/*
- * The 'big kernel semaphore'
- *
- * This mutex 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.
- *
- * Note: code locked by this semaphore will only be serialized against
- * other code using the same locking facility. The code guarantees that
- * the task remains on the same CPU.
- *
- * Don't use in new code.
- */
-static DECLARE_MUTEX(kernel_sem);
-
-/*
- * Re-acquire the kernel semaphore.
- *
- * This function is called with preemption off.
- *
- * We are executing in schedule() so the code must be extremely careful
- * about recursion, both due to the down() and due to the enabling of
- * preemption. schedule() will re-check the preemption flag after
- * reacquiring the semaphore.
- */
-int __lockfunc __reacquire_kernel_lock(void)
-{
-       struct task_struct *task = current;
-       int saved_lock_depth = task->lock_depth;
-
-       BUG_ON(saved_lock_depth < 0);
-
-       task->lock_depth = -1;
-       preempt_enable_no_resched();
-
-       down(&kernel_sem);
-
-       preempt_disable();
-       task->lock_depth = saved_lock_depth;
-
-       return 0;
-}
-
-void __lockfunc __release_kernel_lock(void)
-{
-       up(&kernel_sem);
-}
-
-/*
- * Getting the big kernel semaphore.
- */
-void __lockfunc lock_kernel(void)
-{
-       struct task_struct *task = current;
-       int depth = task->lock_depth + 1;
-
-       if (likely(!depth))
-               /*
-                * No recursion worries - we set up lock_depth _after_
-                */
-               down(&kernel_sem);
-
-       task->lock_depth = depth;
-}
-
-void __lockfunc unlock_kernel(void)
-{
-       struct task_struct *task = current;
-
-       BUG_ON(task->lock_depth < 0);
-
-       if (likely(--task->lock_depth < 0))
-               up(&kernel_sem);
-}
-
-#else
+#include <linux/semaphore.h>
 
 /*
  * The 'big kernel lock'
@@ -117,7 +39,7 @@ static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(kernel_flag);
 int __lockfunc __reacquire_kernel_lock(void)
 {
        while (!_raw_spin_trylock(&kernel_flag)) {
-               if (test_thread_flag(TIF_NEED_RESCHED))
+               if (need_resched())
                        return -EAGAIN;
                cpu_relax();
        }
@@ -132,7 +54,7 @@ void __lockfunc __release_kernel_lock(void)
 }
 
 /*
- * These are the BKL spinlocks - we try to be polite about preemption. 
+ * 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.
  */
@@ -177,7 +99,12 @@ static inline void __lock_kernel(void)
 
 static inline void __unlock_kernel(void)
 {
-       spin_unlock(&kernel_flag);
+       /*
+        * 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();
 }
 
 /*
@@ -201,8 +128,6 @@ void __lockfunc unlock_kernel(void)
                __unlock_kernel();
 }
 
-#endif
-
 EXPORT_SYMBOL(lock_kernel);
 EXPORT_SYMBOL(unlock_kernel);