Messages in this thread Patch in this message | | | Date | Wed, 2 Apr 2008 14:47:50 -0700 | From | Randy Dunlap <> | Subject | [PATCH] docbook: some kernel-locking fixes |
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From: Matti Linnanvuori <mattilinnanvuori@yahoo.com>
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@yahoo.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
--- Documentation/DocBook/kernel-locking.tmpl | 25 +++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-)
--- lin2625-rc8-kdoc.orig/Documentation/DocBook/kernel-locking.tmpl +++ lin2625-rc8-kdoc/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>
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