const: constify remaining file_operations

[safe/jmp/linux-2.6] / include / linux / completion.h

diff --git a/include/linux/completion.h b/include/linux/completion.h
index 57faa60..4a6b604 100644 (file)
--- a/include/linux/completion.h
+++ b/include/linux/completion.h
@@ -10,6 +10,18 @@
 
 #include <linux/wait.h>
 
+/**
+ * struct completion - structure used to maintain state for a "completion"
+ *
+ * This is the opaque structure used to maintain the state for a "completion".
+ * Completions currently use a FIFO to queue threads that have to wait for
+ * the "completion" event.
+ *
+ * See also:  complete(), wait_for_completion() (and friends _timeout,
+ * _interruptible, _interruptible_timeout, and _killable), init_completion(),
+ * and macros DECLARE_COMPLETION(), DECLARE_COMPLETION_ONSTACK(), and
+ * INIT_COMPLETION().
+ */
 struct completion {
        unsigned int done;
        wait_queue_head_t wait;
@@ -21,6 +33,14 @@ struct completion {
 #define COMPLETION_INITIALIZER_ONSTACK(work) \
        ({ init_completion(&work); work; })
 
+/**
+ * DECLARE_COMPLETION: - declare and initialize a completion structure
+ * @work:  identifier for the completion structure
+ *
+ * This macro declares and initializes a completion structure. Generally used
+ * for static declarations. You should use the _ONSTACK variant for automatic
+ * variables.
+ */
 #define DECLARE_COMPLETION(work) \
        struct completion work = COMPLETION_INITIALIZER(work)
 
@@ -29,6 +49,13 @@ struct completion {
  * completions - so we use the _ONSTACK() variant for those that
  * are on the kernel stack:
  */
+/**
+ * DECLARE_COMPLETION_ONSTACK: - declare and initialize a completion structure
+ * @work:  identifier for the completion structure
+ *
+ * This macro declares and initializes a completion structure on the kernel
+ * stack.
+ */
 #ifdef CONFIG_LOCKDEP
 # define DECLARE_COMPLETION_ONSTACK(work) \
        struct completion work = COMPLETION_INITIALIZER_ONSTACK(work)
@@ -36,6 +63,13 @@ struct completion {
 # define DECLARE_COMPLETION_ONSTACK(work) DECLARE_COMPLETION(work)
 #endif
 
+/**
+ * init_completion: - Initialize a dynamically allocated completion
+ * @x:  completion structure that is to be initialized
+ *
+ * This inline function will initialize a dynamically created completion
+ * structure.
+ */
 static inline void init_completion(struct completion *x)
 {
        x->done = 0;
@@ -49,55 +83,20 @@ extern unsigned long wait_for_completion_timeout(struct completion *x,
                                                   unsigned long timeout);
 extern unsigned long wait_for_completion_interruptible_timeout(
                        struct completion *x, unsigned long timeout);
+extern bool try_wait_for_completion(struct completion *x);
+extern bool completion_done(struct completion *x);
 
 extern void complete(struct completion *);
 extern void complete_all(struct completion *);
 
-#define INIT_COMPLETION(x)     ((x).done = 0)
-
-
-/**
- *     try_wait_for_completion - try to decrement a completion without blocking
- *     @x:     completion structure
- *
- *     Returns: 0 if a decrement cannot be done without blocking
- *              1 if a decrement succeeded.
- *
- *     If a completion is being used as a counting completion,
- *     attempt to decrement the counter without blocking. This
- *     enables us to avoid waiting if the resource the completion
- *     is protecting is not available.
- */
-static inline bool try_wait_for_completion(struct completion *x)
-{
-       int ret = 1;
-
-       spin_lock_irq(&x->wait.lock);
-       if (!x->done)
-               ret = 0;
-       else
-               x->done--;
-       spin_unlock_irq(&x->wait.lock);
-       return ret;
-}
-
 /**
- *     completion_done - Test to see if a completion has any waiters
- *     @x:     completion structure
- *
- *     Returns: 0 if there are waiters (wait_for_completion() in progress)
- *              1 if there are no waiters.
+ * INIT_COMPLETION: - reinitialize a completion structure
+ * @x:  completion structure to be reinitialized
  *
+ * This macro should be used to reinitialize a completion structure so it can
+ * be reused. This is especially important after complete_all() is used.
  */
-static inline bool completion_done(struct completion *x)
-{
-       int ret = 1;
+#define INIT_COMPLETION(x)     ((x).done = 0)
 
-       spin_lock_irq(&x->wait.lock);
-       if (!x->done)
-               ret = 0;
-       spin_unlock_irq(&x->wait.lock);
-       return ret;
-}
 
 #endif