[PATCH 008 of 19] knfsd: lockd: make the hash chains use a hlist_node

NeilBrown
2006-09-01T04:39:32Z

From: Olaf Kirch <okir@suse.de>

Get rid of the home-grown singly linked lists for the
nlm_host hash table.

Signed-off-by: Olaf Kirch <okir@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
./fs/lockd/host.c | 71 +++++++++++++++++++++++-------------------
./include/linux/lockd/lockd.h | 2 -
2 files changed, 40 insertions(+), 33 deletions(-)

diff .prev/fs/lockd/host.c ./fs/lockd/host.c
--- .prev/fs/lockd/host.c 2006-09-01 10:42:33.000000000 +1000
+++ ./fs/lockd/host.c 2006-08-31 17:32:46.000000000 +1000
@@ -27,7 +27,7 @@
#define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
#define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ)

-static struct nlm_host * nlm_hosts[NLM_HOST_NRHASH];
+static struct hlist_head nlm_hosts[NLM_HOST_NRHASH];
static unsigned long next_gc;
static int nrhosts;
static DEFINE_MUTEX(nlm_host_mutex);
@@ -69,7 +69,9 @@ nlm_lookup_host(int server, const struct
const char *hostname,
int hostname_len)
{
- struct nlm_host *host, **hp;
+ struct hlist_head *chain;
+ struct hlist_node *pos;
+ struct nlm_host *host;
struct nsm_handle *nsm = NULL;
int hash;

@@ -95,7 +97,8 @@ nlm_lookup_host(int server, const struct
* different NLM rpc_clients into one single nlm_host object.
* This would allow us to have one nlm_host per address.
*/
- for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
+ chain = &nlm_hosts[hash];
+ hlist_for_each_entry(host, pos, chain, h_hash) {
if (!nlm_cmp_addr(&host->h_addr, sin))
continue;

@@ -110,15 +113,16 @@ nlm_lookup_host(int server, const struct
if (host->h_server != server)
continue;

- if (hp != nlm_hosts + hash) {
- *hp = host->h_next;
- host->h_next = nlm_hosts[hash];
- nlm_hosts[hash] = host;
- }
+ /* Move to head of hash chain. */
+ hlist_del(&host->h_hash);
+ hlist_add_head(&host->h_hash, chain);
+
nlm_get_host(host);
goto out;
}

+ host = NULL;
+
/* Sadly, the host isn't in our hash table yet. See if
* we have an NSM handle for it. If not, create one.
*/
@@ -146,8 +150,7 @@ nlm_lookup_host(int server, const struct
host->h_nsmstate = 0; /* real NSM state */
host->h_nsmhandle = nsm;
host->h_server = server;
- host->h_next = nlm_hosts[hash];
- nlm_hosts[hash] = host;
+ hlist_add_head(&host->h_hash, chain);
INIT_LIST_HEAD(&host->h_lockowners);
spin_lock_init(&host->h_lock);
INIT_LIST_HEAD(&host->h_granted);
@@ -164,14 +167,17 @@ out:
struct nlm_host *
nlm_find_client(void)
{
+ struct hlist_head *chain;
+ struct hlist_node *pos;
+
/* find a nlm_host for a client for which h_killed == 0.
* and return it
*/
- int hash;
mutex_lock(&nlm_host_mutex);
- for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) {
- struct nlm_host *host, **hp;
- for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
+ for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
+ struct nlm_host *host;
+
+ hlist_for_each_entry(host, pos, chain, h_hash) {
if (host->h_server &&
host->h_killed == 0) {
nlm_get_host(host);
@@ -294,9 +300,10 @@ void nlm_host_rebooted(const struct sock
const char *hostname, int hostname_len,
u32 new_state)
{
+ struct hlist_head *chain;
+ struct hlist_node *pos;
struct nsm_handle *nsm;
- struct nlm_host *host, **hp;
- int hash;
+ struct nlm_host *host;

dprintk("lockd: nlm_host_rebooted(%s, %u.%u.%u.%u)\n",
hostname, NIPQUAD(sin->sin_addr));
@@ -315,8 +322,8 @@ void nlm_host_rebooted(const struct sock
* To avoid processing a host several times, we match the nsmstate.
*/
again: mutex_lock(&nlm_host_mutex);
- for (hash = 0; hash < NLM_HOST_NRHASH; hash++) {
- for (hp = &nlm_hosts[hash]; (host = *hp); hp = &host->h_next) {
+ for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
+ hlist_for_each_entry(host, pos, chain, h_hash) {
if (host->h_nsmhandle == nsm
&& host->h_nsmstate != new_state) {
host->h_nsmstate = new_state;
@@ -350,16 +357,17 @@ again: mutex_lock(&nlm_host_mutex);
void
nlm_shutdown_hosts(void)
{
+ struct hlist_head *chain;
+ struct hlist_node *pos;
struct nlm_host *host;
- int i;

dprintk("lockd: shutting down host module\n");
mutex_lock(&nlm_host_mutex);

/* First, make all hosts eligible for gc */
dprintk("lockd: nuking all hosts...\n");
- for (i = 0; i < NLM_HOST_NRHASH; i++) {
- for (host = nlm_hosts[i]; host; host = host->h_next)
+ for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
+ hlist_for_each_entry(host, pos, chain, h_hash)
host->h_expires = jiffies - 1;
}

@@ -371,8 +379,8 @@ nlm_shutdown_hosts(void)
if (nrhosts) {
printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
dprintk("lockd: %d hosts left:\n", nrhosts);
- for (i = 0; i < NLM_HOST_NRHASH; i++) {
- for (host = nlm_hosts[i]; host; host = host->h_next) {
+ for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
+ hlist_for_each_entry(host, pos, chain, h_hash) {
dprintk(" %s (cnt %d use %d exp %ld)\n",
host->h_name, atomic_read(&host->h_count),
host->h_inuse, host->h_expires);
@@ -389,32 +397,31 @@ nlm_shutdown_hosts(void)
static void
nlm_gc_hosts(void)
{
- struct nlm_host **q, *host;
+ struct hlist_head *chain;
+ struct hlist_node *pos, *next;
+ struct nlm_host *host;
struct rpc_clnt *clnt;
- int i;

dprintk("lockd: host garbage collection\n");
- for (i = 0; i < NLM_HOST_NRHASH; i++) {
- for (host = nlm_hosts[i]; host; host = host->h_next)
+ for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
+ hlist_for_each_entry(host, pos, chain, h_hash)
host->h_inuse = 0;
}

/* Mark all hosts that hold locks, blocks or shares */
nlmsvc_mark_resources();

- for (i = 0; i < NLM_HOST_NRHASH; i++) {
- q = &nlm_hosts[i];
- while ((host = *q) != NULL) {
+ for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
+ hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
if (atomic_read(&host->h_count) || host->h_inuse
|| time_before(jiffies, host->h_expires)) {
dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
host->h_name, atomic_read(&host->h_count),
host->h_inuse, host->h_expires);
- q = &host->h_next;
continue;
}
dprintk("lockd: delete host %s\n", host->h_name);
- *q = host->h_next;
+ hlist_del_init(&host->h_hash);

/*
* Unmonitor unless host was invalidated (i.e. lockd restarted)

diff .prev/include/linux/lockd/lockd.h ./include/linux/lockd/lockd.h
--- .prev/include/linux/lockd/lockd.h 2006-09-01 10:42:33.000000000 +1000
+++ ./include/linux/lockd/lockd.h 2006-09-01 10:42:31.000000000 +1000
@@ -37,7 +37,7 @@
* Lockd host handle (used both by the client and server personality).
*/
struct nlm_host {
- struct nlm_host * h_next; /* linked list (hash table) */
+ struct hlist_node h_hash; /* doubly linked list */
struct sockaddr_in h_addr; /* peer address */
struct rpc_clnt * h_rpcclnt; /* RPC client to talk to peer */
char * h_name; /* remote hostname */