Revert "RDS: Congestion-handling code"

This reverts commit 922cb17a5c812fcc9ebee249f4109db099896941.

1 files changed, 0 insertions, 402 deletions

diff --git a/net/rds/cong.c b/net/rds/cong.c
deleted file mode 100644
index 90e6b31d8e8a..000000000000
--- a/net/rds/cong.c
+++ /dev/null
@@ -1,402 +0,0 @@
-/*
- * Copyright (c) 2007 Oracle.  All rights reserved.
- *
- * This software is available to you under a choice of one of two
- * licenses.  You may choose to be licensed under the terms of the GNU
- * General Public License (GPL) Version 2, available from the file
- * COPYING in the main directory of this source tree, or the
- * OpenIB.org BSD license below:
- *
- *     Redistribution and use in source and binary forms, with or
- *     without modification, are permitted provided that the following
- *     conditions are met:
- *
- *      - Redistributions of source code must retain the above
- *        copyright notice, this list of conditions and the following
- *        disclaimer.
- *
- *      - Redistributions in binary form must reproduce the above
- *        copyright notice, this list of conditions and the following
- *        disclaimer in the documentation and/or other materials
- *        provided with the distribution.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
- * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
- * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- *
- */
-#include <linux/types.h>
-#include <linux/rbtree.h>
-
-#include "rds.h"
-
-/*
- * This file implements the receive side of the unconventional congestion
- * management in RDS.
- *
- * Messages waiting in the receive queue on the receiving socket are accounted
- * against the sockets SO_RCVBUF option value.  Only the payload bytes in the
- * message are accounted for.  If the number of bytes queued equals or exceeds
- * rcvbuf then the socket is congested.  All sends attempted to this socket's
- * address should return block or return -EWOULDBLOCK.
- *
- * Applications are expected to be reasonably tuned such that this situation
- * very rarely occurs.  An application encountering this "back-pressure" is
- * considered a bug.
- *
- * This is implemented by having each node maintain bitmaps which indicate
- * which ports on bound addresses are congested.  As the bitmap changes it is
- * sent through all the connections which terminate in the local address of the
- * bitmap which changed.
- *
- * The bitmaps are allocated as connections are brought up.  This avoids
- * allocation in the interrupt handling path which queues messages on sockets.
- * The dense bitmaps let transports send the entire bitmap on any bitmap change
- * reasonably efficiently.  This is much easier to implement than some
- * finer-grained communication of per-port congestion.  The sender does a very
- * inexpensive bit test to test if the port it's about to send to is congested
- * or not.
- */
-
-/*
- * Interaction with poll is a tad tricky. We want all processes stuck in
- * poll to wake up and check whether a congested destination became uncongested.
- * The really sad thing is we have no idea which destinations the application
- * wants to send to - we don't even know which rds_connections are involved.
- * So until we implement a more flexible rds poll interface, we have to make
- * do with this:
- * We maintain a global counter that is incremented each time a congestion map
- * update is received. Each rds socket tracks this value, and if rds_poll
- * finds that the saved generation number is smaller than the global generation
- * number, it wakes up the process.
- */
-static atomic_t		rds_cong_generation = ATOMIC_INIT(0);
-
-/*
- * Congestion monitoring
- */
-static LIST_HEAD(rds_cong_monitor);
-static DEFINE_RWLOCK(rds_cong_monitor_lock);
-
-/*
- * Yes, a global lock.  It's used so infrequently that it's worth keeping it
- * global to simplify the locking.  It's only used in the following
- * circumstances:
- *
- *  - on connection buildup to associate a conn with its maps
- *  - on map changes to inform conns of a new map to send
- *
- *  It's sadly ordered under the socket callback lock and the connection lock.
- *  Receive paths can mark ports congested from interrupt context so the
- *  lock masks interrupts.
- */
-static DEFINE_SPINLOCK(rds_cong_lock);
-static struct rb_root rds_cong_tree = RB_ROOT;
-
-static struct rds_cong_map *rds_cong_tree_walk(__be32 addr,
-					       struct rds_cong_map *insert)
-{
-	struct rb_node **p = &rds_cong_tree.rb_node;
-	struct rb_node *parent = NULL;
-	struct rds_cong_map *map;
-
-	while (*p) {
-		parent = *p;
-		map = rb_entry(parent, struct rds_cong_map, m_rb_node);
-
-		if (addr < map->m_addr)
-			p = &(*p)->rb_left;
-		else if (addr > map->m_addr)
-			p = &(*p)->rb_right;
-		else
-			return map;
-	}
-
-	if (insert) {
-		rb_link_node(&insert->m_rb_node, parent, p);
-		rb_insert_color(&insert->m_rb_node, &rds_cong_tree);
-	}
-	return NULL;
-}
-
-/*
- * There is only ever one bitmap for any address.  Connections try and allocate
- * these bitmaps in the process getting pointers to them.  The bitmaps are only
- * ever freed as the module is removed after all connections have been freed.
- */
-static struct rds_cong_map *rds_cong_from_addr(__be32 addr)
-{
-	struct rds_cong_map *map;
-	struct rds_cong_map *ret = NULL;
-	unsigned long zp;
-	unsigned long i;
-	unsigned long flags;
-
-	map = kzalloc(sizeof(struct rds_cong_map), GFP_KERNEL);
-	if (map == NULL)
-		return NULL;
-
-	map->m_addr = addr;
-	init_waitqueue_head(&map->m_waitq);
-	INIT_LIST_HEAD(&map->m_conn_list);
-
-	for (i = 0; i < RDS_CONG_MAP_PAGES; i++) {
-		zp = get_zeroed_page(GFP_KERNEL);
-		if (zp == 0)
-			goto out;
-		map->m_page_addrs[i] = zp;
-	}
-
-	spin_lock_irqsave(&rds_cong_lock, flags);
-	ret = rds_cong_tree_walk(addr, map);
-	spin_unlock_irqrestore(&rds_cong_lock, flags);
-
-	if (ret == NULL) {
-		ret = map;
-		map = NULL;
-	}
-
-out:
-	if (map) {
-		for (i = 0; i < RDS_CONG_MAP_PAGES && map->m_page_addrs[i]; i++)
-			free_page(map->m_page_addrs[i]);
-		kfree(map);
-	}
-
-	rdsdebug("map %p for addr %x\n", ret, be32_to_cpu(addr));
-
-	return ret;
-}
-
-/*
- * Put the conn on its local map's list.  This is called when the conn is
- * really added to the hash.  It's nested under the rds_conn_lock, sadly.
- */
-void rds_cong_add_conn(struct rds_connection *conn)
-{
-	unsigned long flags;
-
-	rdsdebug("conn %p now on map %p\n", conn, conn->c_lcong);
-	spin_lock_irqsave(&rds_cong_lock, flags);
-	list_add_tail(&conn->c_map_item, &conn->c_lcong->m_conn_list);
-	spin_unlock_irqrestore(&rds_cong_lock, flags);
-}
-
-void rds_cong_remove_conn(struct rds_connection *conn)
-{
-	unsigned long flags;
-
-	rdsdebug("removing conn %p from map %p\n", conn, conn->c_lcong);
-	spin_lock_irqsave(&rds_cong_lock, flags);
-	list_del_init(&conn->c_map_item);
-	spin_unlock_irqrestore(&rds_cong_lock, flags);
-}
-
-int rds_cong_get_maps(struct rds_connection *conn)
-{
-	conn->c_lcong = rds_cong_from_addr(conn->c_laddr);
-	conn->c_fcong = rds_cong_from_addr(conn->c_faddr);
-
-	if (conn->c_lcong == NULL || conn->c_fcong == NULL)
-		return -ENOMEM;
-
-	return 0;
-}
-
-void rds_cong_queue_updates(struct rds_cong_map *map)
-{
-	struct rds_connection *conn;
-	unsigned long flags;
-
-	spin_lock_irqsave(&rds_cong_lock, flags);
-
-	list_for_each_entry(conn, &map->m_conn_list, c_map_item) {
-		if (!test_and_set_bit(0, &conn->c_map_queued)) {
-			rds_stats_inc(s_cong_update_queued);
-			queue_delayed_work(rds_wq, &conn->c_send_w, 0);
-		}
-	}
-
-	spin_unlock_irqrestore(&rds_cong_lock, flags);
-}
-
-void rds_cong_map_updated(struct rds_cong_map *map, uint64_t portmask)
-{
-	rdsdebug("waking map %p for %pI4\n",
-	  map, &map->m_addr);
-	rds_stats_inc(s_cong_update_received);
-	atomic_inc(&rds_cong_generation);
-	if (waitqueue_active(&map->m_waitq))
-		wake_up(&map->m_waitq);
-	if (waitqueue_active(&rds_poll_waitq))
-		wake_up_all(&rds_poll_waitq);
-
-	if (portmask && !list_empty(&rds_cong_monitor)) {
-		unsigned long flags;
-		struct rds_sock *rs;
-
-		read_lock_irqsave(&rds_cong_monitor_lock, flags);
-		list_for_each_entry(rs, &rds_cong_monitor, rs_cong_list) {
-			spin_lock(&rs->rs_lock);
-			rs->rs_cong_notify |= (rs->rs_cong_mask & portmask);
-			rs->rs_cong_mask &= ~portmask;
-			spin_unlock(&rs->rs_lock);
-			if (rs->rs_cong_notify)
-				rds_wake_sk_sleep(rs);
-		}
-		read_unlock_irqrestore(&rds_cong_monitor_lock, flags);
-	}
-}
-
-int rds_cong_updated_since(unsigned long *recent)
-{
-	unsigned long gen = atomic_read(&rds_cong_generation);
-
-	if (likely(*recent == gen))
-		return 0;
-	*recent = gen;
-	return 1;
-}
-
-/*
- * We're called under the locking that protects the sockets receive buffer
- * consumption.  This makes it a lot easier for the caller to only call us
- * when it knows that an existing set bit needs to be cleared, and vice versa.
- * We can't block and we need to deal with concurrent sockets working against
- * the same per-address map.
- */
-void rds_cong_set_bit(struct rds_cong_map *map, __be16 port)
-{
-	unsigned long i;
-	unsigned long off;
-
-	rdsdebug("setting congestion for %pI4:%u in map %p\n",
-	  &map->m_addr, ntohs(port), map);
-
-	i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS;
-	off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS;
-
-	generic___set_le_bit(off, (void *)map->m_page_addrs[i]);
-}
-
-void rds_cong_clear_bit(struct rds_cong_map *map, __be16 port)
-{
-	unsigned long i;
-	unsigned long off;
-
-	rdsdebug("clearing congestion for %pI4:%u in map %p\n",
-	  &map->m_addr, ntohs(port), map);
-
-	i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS;
-	off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS;
-
-	generic___clear_le_bit(off, (void *)map->m_page_addrs[i]);
-}
-
-static int rds_cong_test_bit(struct rds_cong_map *map, __be16 port)
-{
-	unsigned long i;
-	unsigned long off;
-
-	i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS;
-	off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS;
-
-	return generic_test_le_bit(off, (void *)map->m_page_addrs[i]);
-}
-
-void rds_cong_add_socket(struct rds_sock *rs)
-{
-	unsigned long flags;
-
-	write_lock_irqsave(&rds_cong_monitor_lock, flags);
-	if (list_empty(&rs->rs_cong_list))
-		list_add(&rs->rs_cong_list, &rds_cong_monitor);
-	write_unlock_irqrestore(&rds_cong_monitor_lock, flags);
-}
-
-void rds_cong_remove_socket(struct rds_sock *rs)
-{
-	unsigned long flags;
-	struct rds_cong_map *map;
-
-	write_lock_irqsave(&rds_cong_monitor_lock, flags);
-	list_del_init(&rs->rs_cong_list);
-	write_unlock_irqrestore(&rds_cong_monitor_lock, flags);
-
-	/* update congestion map for now-closed port */
-	spin_lock_irqsave(&rds_cong_lock, flags);
-	map = rds_cong_tree_walk(rs->rs_bound_addr, NULL);
-	spin_unlock_irqrestore(&rds_cong_lock, flags);
-
-	if (map && rds_cong_test_bit(map, rs->rs_bound_port)) {
-		rds_cong_clear_bit(map, rs->rs_bound_port);
-		rds_cong_queue_updates(map);
-	}
-}
-
-int rds_cong_wait(struct rds_cong_map *map, __be16 port, int nonblock,
-		  struct rds_sock *rs)
-{
-	if (!rds_cong_test_bit(map, port))
-		return 0;
-	if (nonblock) {
-		if (rs && rs->rs_cong_monitor) {
-			unsigned long flags;
-
-			/* It would have been nice to have an atomic set_bit on
-			 * a uint64_t. */
-			spin_lock_irqsave(&rs->rs_lock, flags);
-			rs->rs_cong_mask |= RDS_CONG_MONITOR_MASK(ntohs(port));
-			spin_unlock_irqrestore(&rs->rs_lock, flags);
-
-			/* Test again - a congestion update may have arrived in
-			 * the meantime. */
-			if (!rds_cong_test_bit(map, port))
-				return 0;
-		}
-		rds_stats_inc(s_cong_send_error);
-		return -ENOBUFS;
-	}
-
-	rds_stats_inc(s_cong_send_blocked);
-	rdsdebug("waiting on map %p for port %u\n", map, be16_to_cpu(port));
-
-	return wait_event_interruptible(map->m_waitq,
-					!rds_cong_test_bit(map, port));
-}
-
-void rds_cong_exit(void)
-{
-	struct rb_node *node;
-	struct rds_cong_map *map;
-	unsigned long i;
-
-	while ((node = rb_first(&rds_cong_tree))) {
-		map = rb_entry(node, struct rds_cong_map, m_rb_node);
-		rdsdebug("freeing map %p\n", map);
-		rb_erase(&map->m_rb_node, &rds_cong_tree);
-		for (i = 0; i < RDS_CONG_MAP_PAGES && map->m_page_addrs[i]; i++)
-			free_page(map->m_page_addrs[i]);
-		kfree(map);
-	}
-}
-
-/*
- * Allocate a RDS message containing a congestion update.
- */
-struct rds_message *rds_cong_update_alloc(struct rds_connection *conn)
-{
-	struct rds_cong_map *map = conn->c_lcong;
-	struct rds_message *rm;
-
-	rm = rds_message_map_pages(map->m_page_addrs, RDS_CONG_MAP_BYTES);
-	if (!IS_ERR(rm))
-		rm->m_inc.i_hdr.h_flags = RDS_FLAG_CONG_BITMAP;
-
-	return rm;
-}