Re: [Fwd: Corrections please ...]

From: Kevin Diggs
Date: Tue Aug 19 2008 - 04:10:56 EST

Dave Chinner wrote:
On Mon, Aug 18, 2008 at 06:53:51PM -0700, Kevin Diggs wrote:

Could someone ... anyone take a look at these kernel doc additions?

.....

+/**
+ * complete: - signals a single thread waiting on this completion
+ * @x: holds the state of this particular completion
+ *
+ * This will wake up a single thread waiting on this completion. If multiple


Your mailer appears to be wrapping lines.


+ * threads are waiting ???
+ */
void complete(struct completion *x)
{
unsigned long flags;


complete() will only wake one waiting thread. If there are multiple
waiters, then further calls to complete() are required to wake them,
or a single call to complete_all() could be used.


EXPORT_SYMBOL(wait_for_completion);

+/**

Take 2 ...

Files attached this time ...

kevin --- include/linux/completion.h.orig 2008-08-13 00:56:52.000000000 -0700
+++ include/linux/completion.h 2008-08-18 13:00:23.000000000 -0700
@@ -10,6 +10,16 @@

#include <linux/wait.h>

+/**
+ * struct completion - structure used to maintain state for a "completion"
+ * @done: counting variable used to signal completion
+ * @wait: internal wait queue head; used for locking and synchronization
+ *
+ * This is the structure used to maintain the state for a "completion". See
+ * also: complete(), wait_for_completion() (and friends _timeout,
+ * _interruptible, _interruptible_timeout, and _killable), init_completion(),
+ * and macros DECLARE_COMPLETION() and INIT_COMPLETION().
+ */
struct completion {
unsigned int done;
wait_queue_head_t wait;
@@ -36,6 +46,13 @@
# 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;
--- kernel/sched.c.orig 2008-08-13 02:22:42.000000000 -0700
+++ kernel/sched.c 2008-08-19 00:42:41.000000000 -0700
@@ -4363,6 +4363,16 @@
}
EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */

+/**
+ * complete: - signals a single thread waiting on this completion
+ * @x: holds the state of this particular completion
+ *
+ * This will wake up a single thread waiting on this completion. If multiple
+ * threads are waiting ??? (looking for comments on which thread/context will
+ * be awakened?)
+ *
+ * See also complete_all().
+ */
void complete(struct completion *x)
{
unsigned long flags;
@@ -4374,6 +4384,12 @@
}
EXPORT_SYMBOL(complete);

+/**
+ * complete_all: - signals all threads waiting on this completion
+ * @x: holds the state of this particular completion
+ *
+ * This will wake up all threads waiting on this particular completion event.
+ */
void complete_all(struct completion *x)
{
unsigned long flags;
@@ -4425,12 +4441,28 @@
return timeout;
}

+/**
+ * wait_for_completion: - waits for completion of a task
+ * @x: holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It is NOT
+ * interruptible and there is no timeout.
+ */
void __sched wait_for_completion(struct completion *x)
{
wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(wait_for_completion);

+/**
+ * wait_for_completion_timeout: - waits for completion of a task (w/timeout)
+ * @x: holds the state of this particular completion
+ * @timeout: timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. The timeout is in jiffies. It is not
+ * interruptible.
+ */
unsigned long __sched
wait_for_completion_timeout(struct completion *x, unsigned long timeout)
{
@@ -4438,6 +4470,13 @@
}
EXPORT_SYMBOL(wait_for_completion_timeout);

+/**
+ * wait_for_completion_interruptible: - waits for completion of a task (w/intr)
+ * @x: holds the state of this particular completion
+ *
+ * This waits for completion of a specific task to be signaled. It is
+ * interruptible.
+ */
int __sched wait_for_completion_interruptible(struct completion *x)
{
long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
@@ -4447,6 +4486,14 @@
}
EXPORT_SYMBOL(wait_for_completion_interruptible);

+/**
+ * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
+ * @x: holds the state of this particular completion
+ * @timeout: timeout value in jiffies
+ *
+ * This waits for either a completion of a specific task to be signaled or for a
+ * specified timeout to expire. It is interruptible. The timeout is in jiffies.
+ */
unsigned long __sched
wait_for_completion_interruptible_timeout(struct completion *x,
unsigned long timeout)
@@ -4455,6 +4502,13 @@
}
EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);

+/**
+ * wait_for_completion_killable: - waits for completion of a task (killable)
+ * @x: holds the state of this particular completion
+ *
+ * This waits to be signaled for completion of a specific task. It can be
+ * interrupted by a kill signal.
+ */
int __sched wait_for_completion_killable(struct completion *x)
{
long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);