lockd: define host_for_each{_safe} macros

We've got a lot of loops like this, and I find them a little easier to
read with the macros.  More such loops are coming.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
[ cel: Forward-ported to 2.6.37 ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/lockd/host.c

@@ -26,6 +26,18 @@
 #define NLM_HOST_COLLECT	(120 * HZ)
 
 static struct hlist_head	nlm_hosts[NLM_HOST_NRHASH];
+
+#define for_each_host(host, pos, chain, table) \
+	for ((chain) = (table); \
+	     (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
+		hlist_for_each_entry((host), (pos), (chain), h_hash)
+
+#define for_each_host_safe(host, pos, next, chain, table) \
+	for ((chain) = (table); \
+	     (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
+		hlist_for_each_entry_safe((host), (pos), (next), \
+						(chain), h_hash)
+
 static unsigned long		next_gc;
 static int			nrhosts;
 static DEFINE_MUTEX(nlm_host_mutex);
@@ -453,8 +465,7 @@ void nlm_host_rebooted(const struct nlm_reboot *info)
 	 * To avoid processing a host several times, we match the nsmstate.
 	 */
 again:	mutex_lock(&nlm_host_mutex);
-	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
-		hlist_for_each_entry(host, pos, chain, h_hash) {
+	for_each_host(host, pos, chain, nlm_hosts) {
 		if (host->h_nsmhandle == nsm
 		 && host->h_nsmstate != info->state) {
 			host->h_nsmstate = info->state;
@@ -476,7 +487,6 @@ again:	mutex_lock(&nlm_host_mutex);
 			goto again;
 		}
 	}
-	}
 	mutex_unlock(&nlm_host_mutex);
 	nsm_release(nsm);
 }
@@ -497,15 +507,13 @@ nlm_shutdown_hosts(void)
 
 	/* First, make all hosts eligible for gc */
 	dprintk("lockd: nuking all hosts...\n");
-	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
-		hlist_for_each_entry(host, pos, chain, h_hash) {
+	for_each_host(host, pos, chain, nlm_hosts) {
 		host->h_expires = jiffies - 1;
 		if (host->h_rpcclnt) {
 			rpc_shutdown_client(host->h_rpcclnt);
 			host->h_rpcclnt = NULL;
 		}
 	}
-	}
 
 	/* Then, perform a garbage collection pass */
 	nlm_gc_hosts();
@@ -515,14 +523,12 @@ nlm_shutdown_hosts(void)
 	if (nrhosts) {
 		printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 		dprintk("lockd: %d hosts left:\n", nrhosts);
-		for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
-			hlist_for_each_entry(host, pos, chain, h_hash) {
+		for_each_host(host, pos, chain, nlm_hosts) {
 			dprintk("       %s (cnt %d use %d exp %ld)\n",
 				host->h_name, atomic_read(&host->h_count),
 				host->h_inuse, host->h_expires);
 		}
 	}
-	}
 }
 
 /*
@@ -538,19 +544,17 @@ nlm_gc_hosts(void)
 	struct nlm_host	*host;
 
 	dprintk("lockd: host garbage collection\n");
-	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
-		hlist_for_each_entry(host, pos, chain, h_hash)
+	for_each_host(host, pos, chain, nlm_hosts)
 		host->h_inuse = 0;
-	}
 
 	/* Mark all hosts that hold locks, blocks or shares */
 	nlmsvc_mark_resources();
 
-	for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
-		hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
+	for_each_host_safe(host, pos, next, chain, nlm_hosts) {
 		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",
+			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);
 			continue;
@@ -561,7 +565,6 @@ nlm_gc_hosts(void)
 		nlm_destroy_host(host);
 		nrhosts--;
 	}
-	}
 
 	next_gc = jiffies + NLM_HOST_COLLECT;
 }