lkml.org 
[lkml]   [2018]   [Mar]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] Improve mutex documentation
On Wed, Mar 14, 2018 at 01:56:31PM -0700, Andrew Morton wrote:
> My memory is weak and our documentation is awful. What does
> mutex_lock_killable() actually do and how does it differ from
> mutex_lock_interruptible()?

From: Matthew Wilcox <mawilcox@microsoft.com>

Add kernel-doc for mutex_lock_killable() and mutex_lock_io(). Reword the
kernel-doc for mutex_lock_interruptible().

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 858a07590e39..2048359f33d2 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -1082,15 +1082,16 @@ static noinline int __sched
__mutex_lock_interruptible_slowpath(struct mutex *lock);

/**
- * mutex_lock_interruptible - acquire the mutex, interruptible
- * @lock: the mutex to be acquired
+ * mutex_lock_interruptible() - Acquire the mutex, interruptible by signals.
+ * @lock: The mutex to be acquired.
*
- * Lock the mutex like mutex_lock(), and return 0 if the mutex has
- * been acquired or sleep until the mutex becomes available. If a
- * signal arrives while waiting for the lock then this function
- * returns -EINTR.
+ * Lock the mutex like mutex_lock(). If a signal is delivered while the
+ * process is sleeping, this function will return without acquiring the
+ * mutex.
*
- * This function is similar to (but not equivalent to) down_interruptible().
+ * Context: Process context.
+ * Return: 0 if the lock was successfully acquired or %-EINTR if a
+ * signal arrived.
*/
int __sched mutex_lock_interruptible(struct mutex *lock)
{
@@ -1104,6 +1105,18 @@ int __sched mutex_lock_interruptible(struct mutex *lock)

EXPORT_SYMBOL(mutex_lock_interruptible);

+/**
+ * mutex_lock_killable() - Acquire the mutex, interruptible by fatal signals.
+ * @lock: The mutex to be acquired.
+ *
+ * Lock the mutex like mutex_lock(). If a signal which will be fatal to
+ * the current process is delivered while the process is sleeping, this
+ * function will return without acquiring the mutex.
+ *
+ * Context: Process context.
+ * Return: 0 if the lock was successfully acquired or %-EINTR if a
+ * fatal signal arrived.
+ */
int __sched mutex_lock_killable(struct mutex *lock)
{
might_sleep();
@@ -1115,6 +1128,16 @@ int __sched mutex_lock_killable(struct mutex *lock)
}
EXPORT_SYMBOL(mutex_lock_killable);

+/**
+ * mutex_lock_io() - Acquire the mutex and mark the process as waiting for I/O
+ * @lock: The mutex to be acquired.
+ *
+ * Lock the mutex like mutex_lock(). While the task is waiting for this
+ * mutex, it will be accounted as being in the IO wait state by the
+ * scheduler.
+ *
+ * Context: Process context.
+ */
void __sched mutex_lock_io(struct mutex *lock)
{
int token;
\
 
 \ /
  Last update: 2018-03-15 12:58    [W:0.227 / U:2.408 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site