[PATCH 8/9] SELinux: Replace custom hash with generic lookup3 in symtab

[siarhei.liakh@concurrent-rt.com]

From: Siarhei Liakh <siarhei.liakh@concurrent-rt.com>

This patch replaces local copy of custom hash function with existing
implementation of lookup3 from the standard Linux library. This change
allows to reduce the amount of custom code with has to be maintained, while
potentially improving overall performance of the hash table in question.

Signed-off-by: Siarhei Liakh <siarhei.liakh@concurrent-rt.com>
---
Please CC me directly in all replies.

 security/selinux/ss/symtab.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/security/selinux/ss/symtab.c b/security/selinux/ss/symtab.c
index dc2ce94165d3..8d189d7683d1 100644
--- a/security/selinux/ss/symtab.c
+++ b/security/selinux/ss/symtab.c
@@ -9,6 +9,16 @@
 #include <linux/errno.h>
 #include "symtab.h"
 
+#ifdef CONFIG_SECURITY_SELINUX_ADVANCED_HASHING
+#include <linux/jhash.h>
+
+static unsigned int symhash(struct hashtab *h, const void *key)
+{
+	return jhash(key, strlen((const char *) key), 0) & (h->size - 1);
+}
+
+#else /* #ifdef CONFIG_SECURITY_SELINUX_ADVANCED_HASHING */
+
 static unsigned int symhash(struct hashtab *h, const void *key)
 {
 	const char *p, *keyp;
@@ -23,6 +33,8 @@ static unsigned int symhash(struct hashtab *h, const void *key)
 	return val & (h->size - 1);
 }
 
+#endif /* #else #ifdef CONFIG_SECURITY_SELINUX_ADVANCED_HASHING */
+
 static int symcmp(struct hashtab *h, const void *key1, const void *key2)
 {
 	const char *keyp1, *keyp2;
-- 
2.17.1