fs/fat: comment fix, fat_bits can be also 32

[linux-2.6-block.git] / kernel / context_tracking.c

diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 937ecdfdf2589cc896522286a4da2e3d4f097bf9..72d59a1a6eb66f54985aa8711e0d55ed46150628 100644 (file)
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -39,15 +39,15 @@ void context_tracking_cpu_set(int cpu)
 }
 
 /**
- * context_tracking_user_enter - Inform the context tracking that the CPU is going to
- *                               enter userspace mode.
+ * context_tracking_enter - Inform the context tracking that the CPU is going
+ *                          enter user or guest space mode.
  *
  * This function must be called right before we switch from the kernel
- * to userspace, when it's guaranteed the remaining kernel instructions
- * to execute won't use any RCU read side critical section because this
- * function sets RCU in extended quiescent state.
+ * to user or guest space, when it's guaranteed the remaining kernel
+ * instructions to execute won't use any RCU read side critical section
+ * because this function sets RCU in extended quiescent state.
  */
-void context_tracking_user_enter(void)
+void context_tracking_enter(enum ctx_state state)
 {
        unsigned long flags;
 
@@ -75,9 +75,8 @@ void context_tracking_user_enter(void)
        WARN_ON_ONCE(!current->mm);
 
        local_irq_save(flags);
-       if ( __this_cpu_read(context_tracking.state) != IN_USER) {
+       if ( __this_cpu_read(context_tracking.state) != state) {
                if (__this_cpu_read(context_tracking.active)) {
-                       trace_user_enter(0);
                        /*
                         * At this stage, only low level arch entry code remains and
                         * then we'll run in userspace. We can assume there won't be
@@ -85,7 +84,10 @@ void context_tracking_user_enter(void)
                         * user_exit() or rcu_irq_enter(). Let's remove RCU's dependency
                         * on the tick.
                         */
-                       vtime_user_enter(current);
+                       if (state == CONTEXT_USER) {
+                               trace_user_enter(0);
+                               vtime_user_enter(current);
+                       }
                        rcu_user_enter();
                }
                /*
@@ -101,24 +103,32 @@ void context_tracking_user_enter(void)
                 * OTOH we can spare the calls to vtime and RCU when context_tracking.active
                 * is false because we know that CPU is not tickless.
                 */
-               __this_cpu_write(context_tracking.state, IN_USER);
+               __this_cpu_write(context_tracking.state, state);
        }
        local_irq_restore(flags);
 }
+NOKPROBE_SYMBOL(context_tracking_enter);
+EXPORT_SYMBOL_GPL(context_tracking_enter);
+
+void context_tracking_user_enter(void)
+{
+       context_tracking_enter(CONTEXT_USER);
+}
 NOKPROBE_SYMBOL(context_tracking_user_enter);
 
 /**
- * context_tracking_user_exit - Inform the context tracking that the CPU is
- *                              exiting userspace mode and entering the kernel.
+ * context_tracking_exit - Inform the context tracking that the CPU is
+ *                         exiting user or guest mode and entering the kernel.
  *
- * This function must be called after we entered the kernel from userspace
- * before any use of RCU read side critical section. This potentially include
- * any high level kernel code like syscalls, exceptions, signal handling, etc...
+ * This function must be called after we entered the kernel from user or
+ * guest space before any use of RCU read side critical section. This
+ * potentially include any high level kernel code like syscalls, exceptions,
+ * signal handling, etc...
  *
  * This call supports re-entrancy. This way it can be called from any exception
  * handler without needing to know if we came from userspace or not.
  */
-void context_tracking_user_exit(void)
+void context_tracking_exit(enum ctx_state state)
 {
        unsigned long flags;
 
@@ -129,20 +139,29 @@ void context_tracking_user_exit(void)
                return;
 
        local_irq_save(flags);
-       if (__this_cpu_read(context_tracking.state) == IN_USER) {
+       if (__this_cpu_read(context_tracking.state) == state) {
                if (__this_cpu_read(context_tracking.active)) {
                        /*
                         * We are going to run code that may use RCU. Inform
                         * RCU core about that (ie: we may need the tick again).
                         */
                        rcu_user_exit();
-                       vtime_user_exit(current);
-                       trace_user_exit(0);
+                       if (state == CONTEXT_USER) {
+                               vtime_user_exit(current);
+                               trace_user_exit(0);
+                       }
                }
-               __this_cpu_write(context_tracking.state, IN_KERNEL);
+               __this_cpu_write(context_tracking.state, CONTEXT_KERNEL);
        }
        local_irq_restore(flags);
 }
+NOKPROBE_SYMBOL(context_tracking_exit);
+EXPORT_SYMBOL_GPL(context_tracking_exit);
+
+void context_tracking_user_exit(void)
+{
+       context_tracking_exit(CONTEXT_USER);
+}
 NOKPROBE_SYMBOL(context_tracking_user_exit);
 
 /**