1 files changed, 161 insertions, 168 deletions

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 5050fe05769b..79f56f16bc2c 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -65,40 +65,6 @@
 #define MAX_SEND_MSG_COUNT 25
 #define DLM_SHUTDOWN_WAIT_TIMEOUT msecs_to_jiffies(10000)
 
-struct cbuf {
-	unsigned int base;
-	unsigned int len;
-	unsigned int mask;
-};
-
-static void cbuf_add(struct cbuf *cb, int n)
-{
-	cb->len += n;
-}
-
-static int cbuf_data(struct cbuf *cb)
-{
-	return ((cb->base + cb->len) & cb->mask);
-}
-
-static void cbuf_init(struct cbuf *cb, int size)
-{
-	cb->base = cb->len = 0;
-	cb->mask = size-1;
-}
-
-static void cbuf_eat(struct cbuf *cb, int n)
-{
-	cb->len  -= n;
-	cb->base += n;
-	cb->base &= cb->mask;
-}
-
-static bool cbuf_empty(struct cbuf *cb)
-{
-	return cb->len == 0;
-}
-
 struct connection {
 	struct socket *sock;	/* NULL if not connected */
 	uint32_t nodeid;	/* So we know who we are in the list */
@@ -117,8 +83,6 @@ struct connection {
 	int (*rx_action) (struct connection *);	/* What to do when active */
 	void (*connect_action) (struct connection *);	/* What to do to connect */
 	void (*shutdown_action)(struct connection *con); /* What to do to shutdown */
-	struct page *rx_page;
-	struct cbuf cb;
 	int retries;
 #define MAX_CONNECT_RETRIES 3
 	struct hlist_node list;
@@ -126,6 +90,10 @@ struct connection {
 	struct work_struct rwork; /* Receive workqueue */
 	struct work_struct swork; /* Send workqueue */
 	wait_queue_head_t shutdown_wait; /* wait for graceful shutdown */
+	unsigned char *rx_buf;
+	int rx_buflen;
+	int rx_leftover;
+	struct rcu_head rcu;
 };
 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
 
@@ -167,8 +135,8 @@ static struct workqueue_struct *recv_workqueue;
 static struct workqueue_struct *send_workqueue;
 
 static struct hlist_head connection_hash[CONN_HASH_SIZE];
-static DEFINE_MUTEX(connections_lock);
-static struct kmem_cache *con_cache;
+static DEFINE_SPINLOCK(connections_lock);
+DEFINE_STATIC_SRCU(connections_srcu);
 
 static void process_recv_sockets(struct work_struct *work);
 static void process_send_sockets(struct work_struct *work);
@@ -184,15 +152,20 @@ static inline int nodeid_hash(int nodeid)
 
 static struct connection *__find_con(int nodeid)
 {
-	int r;
+	int r, idx;
 	struct connection *con;
 
 	r = nodeid_hash(nodeid);
 
-	hlist_for_each_entry(con, &connection_hash[r], list) {
-		if (con->nodeid == nodeid)
+	idx = srcu_read_lock(&connections_srcu);
+	hlist_for_each_entry_rcu(con, &connection_hash[r], list) {
+		if (con->nodeid == nodeid) {
+			srcu_read_unlock(&connections_srcu, idx);
 			return con;
+		}
 	}
+	srcu_read_unlock(&connections_srcu, idx);
+
 	return NULL;
 }
 
@@ -200,21 +173,25 @@ static struct connection *__find_con(int nodeid)
  * If 'allocation' is zero then we don't attempt to create a new
  * connection structure for this node.
  */
-static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
+static struct connection *nodeid2con(int nodeid, gfp_t alloc)
 {
-	struct connection *con = NULL;
+	struct connection *con, *tmp;
 	int r;
 
 	con = __find_con(nodeid);
 	if (con || !alloc)
 		return con;
 
-	con = kmem_cache_zalloc(con_cache, alloc);
+	con = kzalloc(sizeof(*con), alloc);
 	if (!con)
 		return NULL;
 
-	r = nodeid_hash(nodeid);
-	hlist_add_head(&con->list, &connection_hash[r]);
+	con->rx_buflen = dlm_config.ci_buffer_size;
+	con->rx_buf = kmalloc(con->rx_buflen, GFP_NOFS);
+	if (!con->rx_buf) {
+		kfree(con);
+		return NULL;
+	}
 
 	con->nodeid = nodeid;
 	mutex_init(&con->sock_mutex);
@@ -233,31 +210,41 @@ static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
 			con->rx_action = zerocon->rx_action;
 	}
 
+	r = nodeid_hash(nodeid);
+
+	spin_lock(&connections_lock);
+	/* Because multiple workqueues/threads calls this function it can
+	 * race on multiple cpu's. Instead of locking hot path __find_con()
+	 * we just check in rare cases of recently added nodes again
+	 * under protection of connections_lock. If this is the case we
+	 * abort our connection creation and return the existing connection.
+	 */
+	tmp = __find_con(nodeid);
+	if (tmp) {
+		spin_unlock(&connections_lock);
+		kfree(con->rx_buf);
+		kfree(con);
+		return tmp;
+	}
+
+	hlist_add_head_rcu(&con->list, &connection_hash[r]);
+	spin_unlock(&connections_lock);
+
 	return con;
 }
 
 /* Loop round all connections */
 static void foreach_conn(void (*conn_func)(struct connection *c))
 {
-	int i;
-	struct hlist_node *n;
+	int i, idx;
 	struct connection *con;
 
+	idx = srcu_read_lock(&connections_srcu);
 	for (i = 0; i < CONN_HASH_SIZE; i++) {
-		hlist_for_each_entry_safe(con, n, &connection_hash[i], list)
+		hlist_for_each_entry_rcu(con, &connection_hash[i], list)
 			conn_func(con);
 	}
-}
-
-static struct connection *nodeid2con(int nodeid, gfp_t allocation)
-{
-	struct connection *con;
-
-	mutex_lock(&connections_lock);
-	con = __nodeid2con(nodeid, allocation);
-	mutex_unlock(&connections_lock);
-
-	return con;
+	srcu_read_unlock(&connections_srcu, idx);
 }
 
 static struct dlm_node_addr *find_node_addr(int nodeid)
@@ -614,11 +601,8 @@ static void close_connection(struct connection *con, bool and_other,
 		/* Will only re-enter once. */
 		close_connection(con->othercon, false, true, true);
 	}
-	if (con->rx_page) {
-		__free_page(con->rx_page);
-		con->rx_page = NULL;
-	}
 
+	con->rx_leftover = 0;
 	con->retries = 0;
 	mutex_unlock(&con->sock_mutex);
 	clear_bit(CF_CLOSING, &con->flags);
@@ -672,16 +656,33 @@ static void dlm_tcp_shutdown(struct connection *con)
 	shutdown_connection(con);
 }
 
+static int con_realloc_receive_buf(struct connection *con, int newlen)
+{
+	unsigned char *newbuf;
+
+	newbuf = kmalloc(newlen, GFP_NOFS);
+	if (!newbuf)
+		return -ENOMEM;
+
+	/* copy any leftover from last receive */
+	if (con->rx_leftover)
+		memmove(newbuf, con->rx_buf, con->rx_leftover);
+
+	/* swap to new buffer space */
+	kfree(con->rx_buf);
+	con->rx_buflen = newlen;
+	con->rx_buf = newbuf;
+
+	return 0;
+}
+
 /* Data received from remote end */
 static int receive_from_sock(struct connection *con)
 {
-	int ret = 0;
-	struct msghdr msg = {};
-	struct kvec iov[2];
-	unsigned len;
-	int r;
 	int call_again_soon = 0;
-	int nvec;
+	struct msghdr msg;
+	struct kvec iov;
+	int ret, buflen;
 
 	mutex_lock(&con->sock_mutex);
 
@@ -689,71 +690,55 @@ static int receive_from_sock(struct connection *con)
 		ret = -EAGAIN;
 		goto out_close;
 	}
+
 	if (con->nodeid == 0) {
 		ret = -EINVAL;
 		goto out_close;
 	}
 
-	if (con->rx_page == NULL) {
-		/*
-		 * This doesn't need to be atomic, but I think it should
-		 * improve performance if it is.
-		 */
-		con->rx_page = alloc_page(GFP_ATOMIC);
-		if (con->rx_page == NULL)
+	/* realloc if we get new buffer size to read out */
+	buflen = dlm_config.ci_buffer_size;
+	if (con->rx_buflen != buflen && con->rx_leftover <= buflen) {
+		ret = con_realloc_receive_buf(con, buflen);
+		if (ret < 0)
 			goto out_resched;
-		cbuf_init(&con->cb, PAGE_SIZE);
 	}
 
-	/*
-	 * iov[0] is the bit of the circular buffer between the current end
-	 * point (cb.base + cb.len) and the end of the buffer.
-	 */
-	iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
-	iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
-	iov[1].iov_len = 0;
-	nvec = 1;
-
-	/*
-	 * iov[1] is the bit of the circular buffer between the start of the
-	 * buffer and the start of the currently used section (cb.base)
+	/* calculate new buffer parameter regarding last receive and
+	 * possible leftover bytes
 	 */
-	if (cbuf_data(&con->cb) >= con->cb.base) {
-		iov[0].iov_len = PAGE_SIZE - cbuf_data(&con->cb);
-		iov[1].iov_len = con->cb.base;
-		iov[1].iov_base = page_address(con->rx_page);
-		nvec = 2;
-	}
-	len = iov[0].iov_len + iov[1].iov_len;
-	iov_iter_kvec(&msg.msg_iter, READ, iov, nvec, len);
+	iov.iov_base = con->rx_buf + con->rx_leftover;
+	iov.iov_len = con->rx_buflen - con->rx_leftover;
 
-	r = ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
+	memset(&msg, 0, sizeof(msg));
+	msg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
+	ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len,
+			     msg.msg_flags);
 	if (ret <= 0)
 		goto out_close;
-	else if (ret == len)
+	else if (ret == iov.iov_len)
 		call_again_soon = 1;
 
-	cbuf_add(&con->cb, ret);
-	ret = dlm_process_incoming_buffer(con->nodeid,
-					  page_address(con->rx_page),
-					  con->cb.base, con->cb.len,
-					  PAGE_SIZE);
-	if (ret < 0) {
-		log_print("lowcomms err %d: addr=%p, base=%u, len=%u, read=%d",
-			  ret, page_address(con->rx_page), con->cb.base,
-			  con->cb.len, r);
-		cbuf_eat(&con->cb, r);
-	} else {
-		cbuf_eat(&con->cb, ret);
-	}
+	/* new buflen according readed bytes and leftover from last receive */
+	buflen = ret + con->rx_leftover;
+	ret = dlm_process_incoming_buffer(con->nodeid, con->rx_buf, buflen);
+	if (ret < 0)
+		goto out_close;
 
-	if (cbuf_empty(&con->cb) && !call_again_soon) {
-		__free_page(con->rx_page);
-		con->rx_page = NULL;
+	/* calculate leftover bytes from process and put it into begin of
+	 * the receive buffer, so next receive we have the full message
+	 * at the start address of the receive buffer.
+	 */
+	con->rx_leftover = buflen - ret;
+	if (con->rx_leftover) {
+		memmove(con->rx_buf, con->rx_buf + ret,
+			con->rx_leftover);
+		call_again_soon = true;
 	}
 
 	if (call_again_soon)
 		goto out_resched;
+
 	mutex_unlock(&con->sock_mutex);
 	return 0;
 
@@ -791,13 +776,11 @@ static int accept_from_sock(struct connection *con)
 	int nodeid;
 	struct connection *newcon;
 	struct connection *addcon;
+	unsigned int mark;
 
-	mutex_lock(&connections_lock);
 	if (!dlm_allow_conn) {
-		mutex_unlock(&connections_lock);
 		return -1;
 	}
-	mutex_unlock(&connections_lock);
 
 	mutex_lock_nested(&con->sock_mutex, 0);
 
@@ -830,6 +813,9 @@ static int accept_from_sock(struct connection *con)
 		return -1;
 	}
 
+	dlm_comm_mark(nodeid, &mark);
+	sock_set_mark(newsock->sk, mark);
+
 	log_print("got connection from %d", nodeid);
 
 	/*  Check to see if we already have a connection to this node. This
@@ -847,13 +833,24 @@ static int accept_from_sock(struct connection *con)
 		struct connection *othercon = newcon->othercon;
 
 		if (!othercon) {
-			othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
+			othercon = kzalloc(sizeof(*othercon), GFP_NOFS);
 			if (!othercon) {
 				log_print("failed to allocate incoming socket");
 				mutex_unlock(&newcon->sock_mutex);
 				result = -ENOMEM;
 				goto accept_err;
 			}
+
+			othercon->rx_buflen = dlm_config.ci_buffer_size;
+			othercon->rx_buf = kmalloc(othercon->rx_buflen, GFP_NOFS);
+			if (!othercon->rx_buf) {
+				mutex_unlock(&newcon->sock_mutex);
+				kfree(othercon);
+				log_print("failed to allocate incoming socket receive buffer");
+				result = -ENOMEM;
+				goto accept_err;
+			}
+
 			othercon->nodeid = nodeid;
 			othercon->rx_action = receive_from_sock;
 			mutex_init(&othercon->sock_mutex);
@@ -975,6 +972,8 @@ static void sctp_connect_to_sock(struct connection *con)
 		return;
 	}
 
+	dlm_comm_mark(con->nodeid, &mark);
+
 	mutex_lock(&con->sock_mutex);
 
 	/* Some odd races can cause double-connects, ignore them */
@@ -999,11 +998,6 @@ static void sctp_connect_to_sock(struct connection *con)
 	if (result < 0)
 		goto socket_err;
 
-	/* set skb mark */
-	result = dlm_comm_mark(con->nodeid, &mark);
-	if (result < 0)
-		goto bind_err;
-
 	sock_set_mark(sock->sk, mark);
 
 	con->rx_action = receive_from_sock;
@@ -1076,6 +1070,8 @@ static void tcp_connect_to_sock(struct connection *con)
 		return;
 	}
 
+	dlm_comm_mark(con->nodeid, &mark);
+
 	mutex_lock(&con->sock_mutex);
 	if (con->retries++ > MAX_CONNECT_RETRIES)
 		goto out;
@@ -1090,11 +1086,6 @@ static void tcp_connect_to_sock(struct connection *con)
 	if (result < 0)
 		goto out_err;
 
-	/* set skb mark */
-	result = dlm_comm_mark(con->nodeid, &mark);
-	if (result < 0)
-		goto out_err;
-
 	sock_set_mark(sock->sk, mark);
 
 	memset(&saddr, 0, sizeof(saddr));
@@ -1238,6 +1229,14 @@ static void init_local(void)
 	}
 }
 
+static void deinit_local(void)
+{
+	int i;
+
+	for (i = 0; i < dlm_local_count; i++)
+		kfree(dlm_local_addr[i]);
+}
+
 /* Initialise SCTP socket and bind to all interfaces */
 static int sctp_listen_for_all(void)
 {
@@ -1546,13 +1545,6 @@ static void process_send_sockets(struct work_struct *work)
 		send_to_sock(con);
 }
 
-
-/* Discard all entries on the write queues */
-static void clean_writequeues(void)
-{
-	foreach_conn(clean_one_writequeue);
-}
-
 static void work_stop(void)
 {
 	if (recv_workqueue)
@@ -1608,26 +1600,34 @@ static void shutdown_conn(struct connection *con)
 		con->shutdown_action(con);
 }
 
+static void connection_release(struct rcu_head *rcu)
+{
+	struct connection *con = container_of(rcu, struct connection, rcu);
+
+	kfree(con->rx_buf);
+	kfree(con);
+}
+
 static void free_conn(struct connection *con)
 {
 	close_connection(con, true, true, true);
-	if (con->othercon)
-		kmem_cache_free(con_cache, con->othercon);
-	hlist_del(&con->list);
-	kmem_cache_free(con_cache, con);
+	spin_lock(&connections_lock);
+	hlist_del_rcu(&con->list);
+	spin_unlock(&connections_lock);
+	if (con->othercon) {
+		clean_one_writequeue(con->othercon);
+		call_rcu(&con->othercon->rcu, connection_release);
+	}
+	clean_one_writequeue(con);
+	call_rcu(&con->rcu, connection_release);
 }
 
 static void work_flush(void)
 {
-	int ok;
+	int ok, idx;
 	int i;
-	struct hlist_node *n;
 	struct connection *con;
 
-	if (recv_workqueue)
-		flush_workqueue(recv_workqueue);
-	if (send_workqueue)
-		flush_workqueue(send_workqueue);
 	do {
 		ok = 1;
 		foreach_conn(stop_conn);
@@ -1635,9 +1635,10 @@ static void work_flush(void)
 			flush_workqueue(recv_workqueue);
 		if (send_workqueue)
 			flush_workqueue(send_workqueue);
+		idx = srcu_read_lock(&connections_srcu);
 		for (i = 0; i < CONN_HASH_SIZE && ok; i++) {
-			hlist_for_each_entry_safe(con, n,
-						  &connection_hash[i], list) {
+			hlist_for_each_entry_rcu(con, &connection_hash[i],
+						 list) {
 				ok &= test_bit(CF_READ_PENDING, &con->flags);
 				ok &= test_bit(CF_WRITE_PENDING, &con->flags);
 				if (con->othercon) {
@@ -1648,6 +1649,7 @@ static void work_flush(void)
 				}
 			}
 		}
+		srcu_read_unlock(&connections_srcu, idx);
 	} while (!ok);
 }
 
@@ -1656,16 +1658,18 @@ void dlm_lowcomms_stop(void)
 	/* Set all the flags to prevent any
 	   socket activity.
 	*/
-	mutex_lock(&connections_lock);
 	dlm_allow_conn = 0;
-	mutex_unlock(&connections_lock);
+
+	if (recv_workqueue)
+		flush_workqueue(recv_workqueue);
+	if (send_workqueue)
+		flush_workqueue(send_workqueue);
+
 	foreach_conn(shutdown_conn);
 	work_flush();
-	clean_writequeues();
 	foreach_conn(free_conn);
 	work_stop();
-
-	kmem_cache_destroy(con_cache);
+	deinit_local();
 }
 
 int dlm_lowcomms_start(void)
@@ -1684,16 +1688,9 @@ int dlm_lowcomms_start(void)
 		goto fail;
 	}
 
-	error = -ENOMEM;
-	con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
-				      __alignof__(struct connection), 0,
-				      NULL);
-	if (!con_cache)
-		goto fail;
-
 	error = work_start();
 	if (error)
-		goto fail_destroy;
+		goto fail;
 
 	dlm_allow_conn = 1;
 
@@ -1710,12 +1707,8 @@ int dlm_lowcomms_start(void)
 fail_unlisten:
 	dlm_allow_conn = 0;
 	con = nodeid2con(0,0);
-	if (con) {
-		close_connection(con, false, true, true);
-		kmem_cache_free(con_cache, con);
-	}
-fail_destroy:
-	kmem_cache_destroy(con_cache);
+	if (con)
+		free_conn(con);
 fail:
 	return error;
 }