[PATCH 7/9] SELinux: Expose filename_tr hash table sizing via Kconfig

[siarhei.liakh@concurrent-rt.com]

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

This change exposes previously hardcoded filename_tr sizing via Kconfig,
which provides a more convenient tuning mechanism for downstream distributions.
Default sizing is not affected.

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

 security/selinux/Kconfig       | 10 ++++++++++
 security/selinux/ss/policydb.c |  3 ++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/security/selinux/Kconfig b/security/selinux/Kconfig
index b7ced53ffd76..23ec741b1ce6 100644
--- a/security/selinux/Kconfig
+++ b/security/selinux/Kconfig
@@ -123,6 +123,16 @@ config SECURITY_SELINUX_AVTAB_HASH_BITS
 	  footprint at price of hash table lookup efficiency. One bucket
 	  per 10 to 100 rules is reasonable.
 
+config SECURITY_SELINUX_PDB_FILE_TR_HASH_BITS
+	int "Number of slots (buckets) for File Transitions hash table, expressed as number of bits (i.e. 2^n)"
+	depends on SECURITY_SELINUX
+	range 1 32
+	default "11"
+	help
+	  This is a power of 2 representing the number of slots (buckets)
+	  used for File Transitions hash table. Smaller value reduces memory
+	  footprint at price of hash table lookup efficiency.
+
 config SECURITY_SELINUX_CHECKREQPROT_VALUE
 	int "NSA SELinux checkreqprot default value"
 	depends on SECURITY_SELINUX
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 0d03036ca20d..f2d809dffb25 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -496,7 +496,8 @@ static int policydb_init(struct policydb *p)
 	cond_policydb_init(p);
 
 	p->filename_trans = hashtab_create(filenametr_hash, filenametr_cmp,
-					   (1 << 11));
+			   (1 << CONFIG_SECURITY_SELINUX_PDB_FILE_TR_HASH_BITS));
+
 	if (!p->filename_trans)
 		return -ENOMEM;
 
-- 
2.17.1