The patch titled
docbook: some kernel-locking fixes
has been added to the -mm tree. Its filename is
docbook-some-kernel-locking-fixes.patch
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------------------------------------------------------
Subject: docbook: some kernel-locking fixes
From: Matti Linnanvuori <mattilinnanvuori@xxxxxxxxx>
Fix a wrong path. Add a chapter about try functions.
http://bugzilla.kernel.org/show_bug.cgi?id=9011
Signed-off-by: Matti Linnanvuori <mattilinnanvuori@xxxxxxxxx>
Signed-off-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/DocBook/kernel-locking.tmpl | 25 +++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff -puN Documentation/DocBook/kernel-locking.tmpl~docbook-some-kernel-locking-fixes Documentation/DocBook/kernel-locking.tmpl
--- a/Documentation/DocBook/kernel-locking.tmpl~docbook-some-kernel-locking-fixes
+++ a/Documentation/DocBook/kernel-locking.tmpl
@@ -290,7 +290,7 @@
<para>
If you have a data structure which is only ever accessed from
user context, then you can use a simple semaphore
- (<filename>linux/asm/semaphore.h</filename>) to protect it. This
+ (<filename>include/asm/semaphore.h</filename>) to protect it. This
is the most trivial case: you initialize the semaphore to the number
of resources available (usually 1), and call
<function>down_interruptible()</function> to grab the semaphore, and
@@ -703,6 +703,29 @@
</sect1>
</chapter>
+<chapter id="try-variants">
+ <title>The try variants</title>
+
+ <para>
+ <function>spin_trylock()</function> does not spin but returns non-zero if
+ it acquires the spinlock on the first try or 0 if not.
+ </para>
+
+ <para>
+ <function>mutex_trylock()</function> does not suspend your task
+ but returns non-zero if it could lock the mutex on the first try
+ or 0 if not.
+ </para>
+
+ <para>
+ <function>down_trylock()</function> does not suspend your task
+ but returns 0 if it could get the semaphore on the first try or
+ non-zero if not. The return value is the inverse of that of
+ <function>spin_trylock()</function> and <function>mutex_trylock()
+ </function>.
+ </para>
+</chapter>
+
<chapter id="Examples">
<title>Common Examples</title>
<para>
_
Patches currently in -mm which might be from mattilinnanvuori@xxxxxxxxx are
origin.patch
docbook-some-kernel-locking-fixes.patch
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