arch/sh/kernel/dwarf.c: use rbtree postorder iteration helper instead of solution using repeated rb_erase()

Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of using repeated rb_erase() calls

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/sh/kernel/dwarf.c

@@ -995,29 +995,19 @@ static struct unwinder dwarf_unwinder = {
 
 static void dwarf_unwinder_cleanup(void)
 {
-	struct rb_node **fde_rb_node = &fde_root.rb_node;
-	struct rb_node **cie_rb_node = &cie_root.rb_node;
+	struct dwarf_fde *fde, *next_fde;
+	struct dwarf_cie *cie, *next_cie;
 
 	/*
 	 * Deallocate all the memory allocated for the DWARF unwinder.
 	 * Traverse all the FDE/CIE lists and remove and free all the
 	 * memory associated with those data structures.
 	 */
-	while (*fde_rb_node) {
-		struct dwarf_fde *fde;
-
-		fde = rb_entry(*fde_rb_node, struct dwarf_fde, node);
-		rb_erase(*fde_rb_node, &fde_root);
+	rbtree_postorder_for_each_entry_safe(fde, next_fde, &fde_root, node)
 		kfree(fde);
-	}
 
-	while (*cie_rb_node) {
-		struct dwarf_cie *cie;
-
-		cie = rb_entry(*cie_rb_node, struct dwarf_cie, node);
-		rb_erase(*cie_rb_node, &cie_root);
+	rbtree_postorder_for_each_entry_safe(cie, next_cie, &cie_root, node)
 		kfree(cie);
-	}
 
 	kmem_cache_destroy(dwarf_reg_cachep);
 	kmem_cache_destroy(dwarf_frame_cachep);