[POWERPC] spufs: Synchronize pte invalidation vs ps close

Make sure the mapping_lock also protects access to the various address_space
pointers used for tearing down the ptes on a spu context switch.

Because unmap_mapping_range can sleep we need to turn mapping_lock from
a spinlock into a sleeping mutex.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index 0a947fd..47617e8 100644
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -55,7 +55,7 @@
 	struct address_space *signal2;	   /* 'signal2' area mappings. */
 	struct address_space *mss;	   /* 'mss' area mappings. */
 	struct address_space *psmap;	   /* 'psmap' area mappings. */
-	spinlock_t mapping_lock;
+	struct mutex mapping_lock;
 	u64 object_id;		   /* user space pointer for oprofile */
 
 	enum { SPU_STATE_RUNNABLE, SPU_STATE_SAVED } state;