new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index dba1ce23..99db616 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -368,7 +368,7 @@
 			return ERR_PTR(-EINVAL);
 
 		neighbor = get_spu_context(
-				SPUFS_I(filp->f_dentry->d_inode)->i_ctx);
+				SPUFS_I(file_inode(filp))->i_ctx);
 
 		if (!list_empty(&neighbor->aff_list) && !(neighbor->aff_head) &&
 		    !list_is_last(&neighbor->aff_list, &gang->aff_list_head) &&