[PATCH v2 10/15] nfsd: make sessionid_hashtbl allocated per net

[Stanislav Kinsbursky <skinsbursky@parallels.com>]

This hash holds established sessions state and closely associated with
nfs4_clients info, which are network namespace aware. So let's make it
allocated per network namespace too.

Note: this hash can be allocated in per-net operations. But it looks
better to allocate it on nfsd state start and thus don't waste resources
if server is not running.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
---
 fs/nfsd/netns.h     |    3 +++
 fs/nfsd/nfs4state.c |   28 +++++++++++++++++-----------
 2 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index 2281f6d..da33d3f 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -32,6 +32,8 @@
 #define LOCKOWNER_INO_HASH_BITS		8
 #define LOCKOWNER_INO_HASH_SIZE		(1 << LOCKOWNER_INO_HASH_BITS)
 
+#define SESSION_HASH_SIZE	512
+
 struct cld_net;
 
 struct nfsd_net {
@@ -65,6 +67,7 @@ struct nfsd_net {
 	struct rb_root unconf_name_tree;
 	struct list_head *ownerstr_hashtbl;
 	struct list_head *lockowner_ino_hashtbl;
+	struct list_head *sessionid_hashtbl;
 };
 
 extern int nfsd_net_id;
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 34006a4..0de2844 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -632,9 +632,6 @@ static void release_openowner(struct nfs4_openowner *oo)
 	nfs4_free_openowner(oo);
 }
 
-#define SESSION_HASH_SIZE	512
-static struct list_head sessionid_hashtbl[SESSION_HASH_SIZE];
-
 static inline int
 hash_sessionid(struct nfs4_sessionid *sessionid)
 {
@@ -928,6 +925,7 @@ static struct nfsd4_session *alloc_session(struct nfsd4_channel_attrs *fchan)
 void init_session(struct svc_rqst *rqstp, struct nfsd4_session *new, struct nfs4_client *clp, struct nfsd4_create_session *cses)
 {
 	int idx;
+	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 
 	new->se_client = clp;
 	gen_sessionid(new);
@@ -941,7 +939,7 @@ void init_session(struct svc_rqst *rqstp, struct nfsd4_session *new, struct nfs4
 	kref_init(&new->se_ref);
 	idx = hash_sessionid(&new->se_sessionid);
 	spin_lock(&client_lock);
-	list_add(&new->se_hash, &sessionid_hashtbl[idx]);
+	list_add(&new->se_hash, &nn->sessionid_hashtbl[idx]);
 	spin_lock(&clp->cl_lock);
 	list_add(&new->se_perclnt, &clp->cl_sessions);
 	spin_unlock(&clp->cl_lock);
@@ -963,15 +961,16 @@ void init_session(struct svc_rqst *rqstp, struct nfsd4_session *new, struct nfs4
 
 /* caller must hold client_lock */
 static struct nfsd4_session *
-find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid)
+find_in_sessionid_hashtbl(struct nfs4_sessionid *sessionid, struct net *net)
 {
 	struct nfsd4_session *elem;
 	int idx;
+	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
 	dump_sessionid(__func__, sessionid);
 	idx = hash_sessionid(sessionid);
 	/* Search in the appropriate list */
-	list_for_each_entry(elem, &sessionid_hashtbl[idx], se_hash) {
+	list_for_each_entry(elem, &nn->sessionid_hashtbl[idx], se_hash) {
 		if (!memcmp(elem->se_sessionid.data, sessionid->data,
 			    NFS4_MAX_SESSIONID_LEN)) {
 			return elem;
@@ -1905,7 +1904,7 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
 	if (!nfsd4_last_compound_op(rqstp))
 		return nfserr_not_only_op;
 	spin_lock(&client_lock);
-	cstate->session = find_in_sessionid_hashtbl(&bcts->sessionid);
+	cstate->session = find_in_sessionid_hashtbl(&bcts->sessionid, SVC_NET(rqstp));
 	/* Sorta weird: we only need the refcnt'ing because new_conn acquires
 	 * client_lock iself: */
 	if (cstate->session) {
@@ -1954,7 +1953,7 @@ nfsd4_destroy_session(struct svc_rqst *r,
 	}
 	dump_sessionid(__func__, &sessionid->sessionid);
 	spin_lock(&client_lock);
-	ses = find_in_sessionid_hashtbl(&sessionid->sessionid);
+	ses = find_in_sessionid_hashtbl(&sessionid->sessionid, SVC_NET(r));
 	if (!ses) {
 		spin_unlock(&client_lock);
 		goto out;
@@ -2050,7 +2049,7 @@ nfsd4_sequence(struct svc_rqst *rqstp,
 
 	spin_lock(&client_lock);
 	status = nfserr_badsession;
-	session = find_in_sessionid_hashtbl(&seq->sessionid);
+	session = find_in_sessionid_hashtbl(&seq->sessionid, SVC_NET(rqstp));
 	if (!session)
 		goto out;
 
@@ -4719,8 +4718,6 @@ nfs4_state_init(void)
 {
 	int i;
 
-	for (i = 0; i < SESSION_HASH_SIZE; i++)
-		INIT_LIST_HEAD(&sessionid_hashtbl[i]);
 	for (i = 0; i < FILE_HASH_SIZE; i++) {
 		INIT_LIST_HEAD(&file_hashtbl[i]);
 	}
@@ -4771,6 +4768,10 @@ static int nfs4_state_start_net(struct net *net)
 			LOCKOWNER_INO_HASH_SIZE, GFP_KERNEL);
 	if (!nn->lockowner_ino_hashtbl)
 		goto err_lockowner_ino;
+	nn->sessionid_hashtbl = kmalloc(sizeof(struct list_head) *
+			SESSION_HASH_SIZE, GFP_KERNEL);
+	if (!nn->sessionid_hashtbl)
+		goto err_sessionid;
 
 	for (i = 0; i < CLIENT_HASH_SIZE; i++) {
 		INIT_LIST_HEAD(&nn->conf_id_hashtbl[i]);
@@ -4780,11 +4781,15 @@ static int nfs4_state_start_net(struct net *net)
 		INIT_LIST_HEAD(&nn->ownerstr_hashtbl[i]);
 	for (i = 0; i < LOCKOWNER_INO_HASH_SIZE; i++)
 		INIT_LIST_HEAD(&nn->lockowner_ino_hashtbl[i]);
+	for (i = 0; i < SESSION_HASH_SIZE; i++)
+		INIT_LIST_HEAD(&nn->sessionid_hashtbl[i]);
 	nn->conf_name_tree = RB_ROOT;
 	nn->unconf_name_tree = RB_ROOT;
 
 	return 0;
 
+err_sessionid:
+	kfree(nn->lockowner_ino_hashtbl);
 err_lockowner_ino:
 	kfree(nn->ownerstr_hashtbl);
 err_ownerstr:
@@ -4819,6 +4824,7 @@ __nfs4_state_shutdown_net(struct net *net)
 		destroy_client(clp);
 	}
 
+	kfree(nn->sessionid_hashtbl);
 	kfree(nn->lockowner_ino_hashtbl);
 	kfree(nn->ownerstr_hashtbl);
 	kfree(nn->unconf_id_hashtbl);