Adopt an approach similar to the RPC server's auth cache (from Aurelien
Charbon and Brian Haley).
Note nlm_lookup_host()'s existing IP address hash function has the same
issue with correctness on little-endian systems as the original IPv4 auth
cache hash function, so I've also updated it with a hash function similar
to the new auth cache hash function.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/lockd/host.c | 49 +++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 43 insertions(+), 6 deletions(-)
diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index dbf3fe6..1f9d72a 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -22,7 +22,6 @@
#define NLMDBG_FACILITY NLMDBG_HOSTCACHE
#define NLM_HOST_NRHASH 32
-#define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1))
#define NLM_HOST_REBIND (60 * HZ)
#define NLM_HOST_EXPIRE (300 * HZ)
#define NLM_HOST_COLLECT (120 * HZ)
@@ -40,6 +39,48 @@ static struct nsm_handle * nsm_find(const struct sockaddr_in *sin,
const char *hostname,
unsigned int hostname_len);
+/*
+ * Hash function must work well on big- and little-endian platforms
+ */
+static unsigned int __nlm_hash32(const __be32 n)
+{
+ unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
+ return hash ^ (hash >> 8);
+}
+
+static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
+{
+ const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
+ return __nlm_hash32(sin->sin_addr.s_addr);
+}
+
+static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
+{
+ const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
+ const struct in6_addr addr = sin6->sin6_addr;
+ return __nlm_hash32(addr.s6_addr32[0]) ^
+ __nlm_hash32(addr.s6_addr32[1]) ^
+ __nlm_hash32(addr.s6_addr32[2]) ^
+ __nlm_hash32(addr.s6_addr32[3]);
+}
+
+static unsigned int nlm_hash_address(const struct sockaddr *sap)
+{
+ unsigned int hash;
+
+ switch (sap->sa_family) {
+ case AF_INET:
+ hash = __nlm_hash_addr4(sap);
+ break;
+ case AF_INET6:
+ hash = __nlm_hash_addr6(sap);
+ break;
+ default:
+ hash = 0;
+ }
+ return hash & (NLM_HOST_NRHASH - 1);
+}
+
static void nlm_clear_port(struct sockaddr *sap)
{
switch (sap->sa_family) {
@@ -92,16 +133,12 @@ static struct nlm_host *nlm_lookup_host(int server,
struct hlist_node *pos;
struct nlm_host *host;
struct nsm_handle *nsm = NULL;
- int hash;
dprintk("lockd: nlm_lookup_host(proto=%d, vers=%u,"
" my role is %s, hostname=%.*s)\n",
proto, version, server ? "server" : "client",
hostname_len, hostname ? hostname : "<none>");
- hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
-
- /* Lock hash table */
mutex_lock(&nlm_host_mutex);
if (time_after_eq(jiffies, next_gc))
@@ -114,7 +151,7 @@ static struct nlm_host *nlm_lookup_host(int server,
* different NLM rpc_clients into one single nlm_host object.
* This would allow us to have one nlm_host per address.
*/
- chain = &nlm_hosts[hash];
+ chain = &nlm_hosts[nlm_hash_address((struct sockaddr *)sin)];
hlist_for_each_entry(host, pos, chain, h_hash) {
if (!nlm_cmp_addr(nlm_addr(host), (struct sockaddr *)sin))
continue;
--
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