[PATCH 81/90] Optimize expand_filename_trans() function

[Daniel J Walsh <dwalsh@xxxxxxxxxx>]

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   This patch looks good to me. acked.

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>From 7b2d68112278f4ce85944c6b65470277de46f420 Mon Sep 17 00:00:00 2001
From: Adam Tkac <atkac@xxxxxxxxxx>
Date: Fri, 25 May 2012 17:42:08 +0200
Subject: [PATCH 81/90] Optimize expand_filename_trans() function, part1.

Currently expand_filename_trans() function use much CPU time to find
end of the state->out->filename_trans list. This is not needed because
data can be prepended instead of appended to the list.

This ends with 10% speed-up of various se* commands (semodule, setsebool).

Signed-off-by: Adam Tkac <atkac@xxxxxxxxxx>
Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
---
 libsepol/src/expand.c |   14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/libsepol/src/expand.c b/libsepol/src/expand.c
index 0c05465..bef759c 100644
--- a/libsepol/src/expand.c
+++ b/libsepol/src/expand.c
@@ -1352,16 +1352,11 @@ static int copy_role_trans(expand_state_t * state, role_trans_rule_t * rules)
 static int expand_filename_trans(expand_state_t *state, filename_trans_rule_t *rules)
 {
 	unsigned int i, j;
-	filename_trans_t *new_trans, *tail, *cur_trans;
+	filename_trans_t *new_trans, *cur_trans;
 	filename_trans_rule_t *cur_rule;
 	ebitmap_t stypes, ttypes;
 	ebitmap_node_t *snode, *tnode;
 
-	/* start at the end of the list */
-	tail = state->out->filename_trans;
-	while (tail && tail->next)
-		tail = tail->next;
-
 	cur_rule = rules;
 	while (cur_rule) {
 		uint32_t mapped_otype;
@@ -1422,11 +1417,8 @@ static int expand_filename_trans(expand_state_t *state, filename_trans_rule_t *r
 					return -1;
 				}
 				memset(new_trans, 0, sizeof(*new_trans));
-				if (tail)
-					tail->next = new_trans;
-				else
-					state->out->filename_trans = new_trans;
-				tail = new_trans;
+				new_trans->next = state->out->filename_trans;
+				state->out->filename_trans = new_trans;
 
 				new_trans->name = strdup(cur_rule->name);
 				if (!new_trans->name) {
-- 
1.7.10.2