tipc: remove files ref.h and ref.c

The reference table is now 'socket aware' instead of being generic,
and has in reality become a socket internal table. In order to be
able to minimize the API exposed by the socket layer towards the rest
of the stack, we now move the reference table definitions and functions
into the file socket.c, and rename the functions accordingly.

There are no functional changes in this commit.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 244 insertions, 3 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 70eaceae1f8c..6a699671245b 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -35,7 +35,6 @@
  */
 
 #include "core.h"
-#include "ref.h"
 #include "name_table.h"
 #include "node.h"
 #include "link.h"
@@ -61,6 +60,11 @@ static int tipc_sk_publish(struct tipc_port *port, uint scope,
 			   struct tipc_name_seq const *seq);
 static int tipc_sk_withdraw(struct tipc_port *port, uint scope,
 			    struct tipc_name_seq const *seq);
+static u32 tipc_sk_ref_acquire(struct tipc_sock *tsk);
+static void tipc_sk_ref_discard(u32 ref);
+static struct tipc_sock *tipc_sk_get(u32 ref);
+static struct tipc_sock *tipc_sk_get_next(u32 *ref);
+static void tipc_sk_put(struct tipc_sock *tsk);
 
 static const struct proto_ops packet_ops;
 static const struct proto_ops stream_ops;
@@ -271,7 +275,7 @@ static int tipc_sk_create(struct net *net, struct socket *sock,
 
 	tsk = tipc_sk(sk);
 	port = &tsk->port;
-	ref = tipc_ref_acquire(tsk);
+	ref = tipc_sk_ref_acquire(tsk);
 	if (!ref) {
 		pr_warn("Socket create failed; reference table exhausted\n");
 		return -ENOMEM;
@@ -434,7 +438,7 @@ static int tipc_release(struct socket *sock)
 	}
 
 	tipc_sk_withdraw(port, 0, NULL);
-	tipc_ref_discard(port->ref);
+	tipc_sk_ref_discard(port->ref);
 	k_cancel_timer(&port->timer);
 	if (port->connected) {
 		buf = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
@@ -2254,6 +2258,243 @@ void tipc_sk_reinit(void)
 }
 
 /**
+ * struct reference - TIPC socket reference entry
+ * @tsk: pointer to socket associated with reference entry
+ * @ref: reference value for socket (combines instance & array index info)
+ */
+struct reference {
+	struct tipc_sock *tsk;
+	u32 ref;
+};
+
+/**
+ * struct tipc_ref_table - table of TIPC socket reference entries
+ * @entries: pointer to array of reference entries
+ * @capacity: array index of first unusable entry
+ * @init_point: array index of first uninitialized entry
+ * @first_free: array index of first unused socket reference entry
+ * @last_free: array index of last unused socket reference entry
+ * @index_mask: bitmask for array index portion of reference values
+ * @start_mask: initial value for instance value portion of reference values
+ */
+struct ref_table {
+	struct reference *entries;
+	u32 capacity;
+	u32 init_point;
+	u32 first_free;
+	u32 last_free;
+	u32 index_mask;
+	u32 start_mask;
+};
+
+/* Socket reference table consists of 2**N entries.
+ *
+ * State	Socket ptr	Reference
+ * -----        ----------      ---------
+ * In use        non-NULL       XXXX|own index
+ *				(XXXX changes each time entry is acquired)
+ * Free            NULL         YYYY|next free index
+ *				(YYYY is one more than last used XXXX)
+ * Uninitialized   NULL         0
+ *
+ * Entry 0 is not used; this allows index 0 to denote the end of the free list.
+ *
+ * Note that a reference value of 0 does not necessarily indicate that an
+ * entry is uninitialized, since the last entry in the free list could also
+ * have a reference value of 0 (although this is unlikely).
+ */
+
+static struct ref_table tipc_ref_table;
+
+static DEFINE_RWLOCK(ref_table_lock);
+
+/**
+ * tipc_ref_table_init - create reference table for sockets
+ */
+int tipc_sk_ref_table_init(u32 req_sz, u32 start)
+{
+	struct reference *table;
+	u32 actual_sz;
+
+	/* account for unused entry, then round up size to a power of 2 */
+
+	req_sz++;
+	for (actual_sz = 16; actual_sz < req_sz; actual_sz <<= 1) {
+		/* do nothing */
+	};
+
+	/* allocate table & mark all entries as uninitialized */
+	table = vzalloc(actual_sz * sizeof(struct reference));
+	if (table == NULL)
+		return -ENOMEM;
+
+	tipc_ref_table.entries = table;
+	tipc_ref_table.capacity = req_sz;
+	tipc_ref_table.init_point = 1;
+	tipc_ref_table.first_free = 0;
+	tipc_ref_table.last_free = 0;
+	tipc_ref_table.index_mask = actual_sz - 1;
+	tipc_ref_table.start_mask = start & ~tipc_ref_table.index_mask;
+
+	return 0;
+}
+
+/**
+ * tipc_ref_table_stop - destroy reference table for sockets
+ */
+void tipc_sk_ref_table_stop(void)
+{
+	if (!tipc_ref_table.entries)
+		return;
+	vfree(tipc_ref_table.entries);
+	tipc_ref_table.entries = NULL;
+}
+
+/* tipc_ref_acquire - create reference to a socket
+ *
+ * Register an socket pointer in the reference table.
+ * Returns a unique reference value that is used from then on to retrieve the
+ * socket pointer, or to determine if the socket has been deregistered.
+ */
+u32 tipc_sk_ref_acquire(struct tipc_sock *tsk)
+{
+	u32 index;
+	u32 index_mask;
+	u32 next_plus_upper;
+	u32 ref = 0;
+	struct reference *entry;
+
+	if (unlikely(!tsk)) {
+		pr_err("Attempt to acquire ref. to non-existent obj\n");
+		return 0;
+	}
+	if (unlikely(!tipc_ref_table.entries)) {
+		pr_err("Ref. table not found in acquisition attempt\n");
+		return 0;
+	}
+
+	/* Take a free entry, if available; otherwise initialize a new one */
+	write_lock_bh(&ref_table_lock);
+	index = tipc_ref_table.first_free;
+	entry = &tipc_ref_table.entries[index];
+
+	if (likely(index)) {
+		index = tipc_ref_table.first_free;
+		entry = &tipc_ref_table.entries[index];
+		index_mask = tipc_ref_table.index_mask;
+		next_plus_upper = entry->ref;
+		tipc_ref_table.first_free = next_plus_upper & index_mask;
+		ref = (next_plus_upper & ~index_mask) + index;
+		entry->tsk = tsk;
+	} else if (tipc_ref_table.init_point < tipc_ref_table.capacity) {
+		index = tipc_ref_table.init_point++;
+		entry = &tipc_ref_table.entries[index];
+		ref = tipc_ref_table.start_mask + index;
+	}
+
+	if (ref) {
+		entry->ref = ref;
+		entry->tsk = tsk;
+	}
+	write_unlock_bh(&ref_table_lock);
+	return ref;
+}
+
+/* tipc_sk_ref_discard - invalidate reference to an socket
+ *
+ * Disallow future references to an socket and free up the entry for re-use.
+ */
+void tipc_sk_ref_discard(u32 ref)
+{
+	struct reference *entry;
+	u32 index;
+	u32 index_mask;
+
+	if (unlikely(!tipc_ref_table.entries)) {
+		pr_err("Ref. table not found during discard attempt\n");
+		return;
+	}
+
+	index_mask = tipc_ref_table.index_mask;
+	index = ref & index_mask;
+	entry = &tipc_ref_table.entries[index];
+
+	write_lock_bh(&ref_table_lock);
+
+	if (unlikely(!entry->tsk)) {
+		pr_err("Attempt to discard ref. to non-existent socket\n");
+		goto exit;
+	}
+	if (unlikely(entry->ref != ref)) {
+		pr_err("Attempt to discard non-existent reference\n");
+		goto exit;
+	}
+
+	/* Mark entry as unused; increment instance part of entry's
+	 *   reference to invalidate any subsequent references
+	 */
+
+	entry->tsk = NULL;
+	entry->ref = (ref & ~index_mask) + (index_mask + 1);
+
+	/* Append entry to free entry list */
+	if (unlikely(tipc_ref_table.first_free == 0))
+		tipc_ref_table.first_free = index;
+	else
+		tipc_ref_table.entries[tipc_ref_table.last_free].ref |= index;
+	tipc_ref_table.last_free = index;
+exit:
+	write_unlock_bh(&ref_table_lock);
+}
+
+/* tipc_sk_get - find referenced socket and return pointer to it
+ */
+struct tipc_sock *tipc_sk_get(u32 ref)
+{
+	struct reference *entry;
+	struct tipc_sock *tsk;
+
+	if (unlikely(!tipc_ref_table.entries))
+		return NULL;
+	read_lock_bh(&ref_table_lock);
+	entry = &tipc_ref_table.entries[ref & tipc_ref_table.index_mask];
+	tsk = entry->tsk;
+	if (likely(tsk && (entry->ref == ref)))
+		sock_hold(&tsk->sk);
+	else
+		tsk = NULL;
+	read_unlock_bh(&ref_table_lock);
+	return tsk;
+}
+
+/* tipc_sk_get_next - lock & return next socket after referenced one
+*/
+struct tipc_sock *tipc_sk_get_next(u32 *ref)
+{
+	struct reference *entry;
+	struct tipc_sock *tsk = NULL;
+	uint index = *ref & tipc_ref_table.index_mask;
+
+	read_lock_bh(&ref_table_lock);
+	while (++index < tipc_ref_table.capacity) {
+		entry = &tipc_ref_table.entries[index];
+		if (!entry->tsk)
+			continue;
+		tsk = entry->tsk;
+		sock_hold(&tsk->sk);
+		*ref = entry->ref;
+		break;
+	}
+	read_unlock_bh(&ref_table_lock);
+	return tsk;
+}
+
+static void tipc_sk_put(struct tipc_sock *tsk)
+{
+	sock_put(&tsk->sk);
+}
+
+/**
  * tipc_setsockopt - set socket option
  * @sock: socket structure
  * @lvl: option level