ACPICA: Fix AcpiWalkNamespace race condition with table unload

Added a reader/writer locking mechanism to allow multiple
concurrent namespace walks (readers), but a dynamic table unload
will have exclusive access to the namespace. This fixes a problem
where a table unload could delete the portion of the namespace that
is currently being examined by a walk.  Adds a new file, utlock.c
that implements the reader/writer lock mechanism. ACPICA BZ 749.

http://www.acpica.org/bugzilla/show_bug.cgi?id=749

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/acpi/acpica/Makefile b/drivers/acpi/acpica/Makefile
index 3f23298ee3fd..290be74b774d 100644
--- a/drivers/acpi/acpica/Makefile
+++ b/drivers/acpi/acpica/Makefile
@@ -41,4 +41,4 @@ obj-y += tbxface.o tbinstal.o tbutils.o tbfind.o tbfadt.o tbxfroot.o
 
 obj-y += utalloc.o utdebug.o uteval.o utinit.o utmisc.o utxface.o \
                 utcopy.o utdelete.o utglobal.o utmath.o utobject.o \
-                utstate.o utmutex.o utobject.o utresrc.o
+                utstate.o utmutex.o utobject.o utresrc.o utlock.o