net/rds/tcp_recv.c - third_party/kernel - Git at Google

 /*
  * Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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/kernel.h>
 #include <linux/slab.h>
 #include <net/tcp.h>

 #include "rds.h"
 #include "tcp.h"

 static struct kmem_cache *rds_tcp_incoming_slab;

 static void rds_tcp_inc_purge(struct rds_incoming *inc)
 {
 	struct rds_tcp_incoming *tinc;
 	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
 	rdsdebug("purging tinc %p inc %p\n", tinc, inc);
 	skb_queue_purge(&tinc->ti_skb_list);
 }

 void rds_tcp_inc_free(struct rds_incoming *inc)
 {
 	struct rds_tcp_incoming *tinc;
 	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
 	rds_tcp_inc_purge(inc);
 	rdsdebug("freeing tinc %p inc %p\n", tinc, inc);
 	kmem_cache_free(rds_tcp_incoming_slab, tinc);
 }

 /*
  * this is pretty lame, but, whatever.
  */
 int rds_tcp_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
 {
 	struct rds_tcp_incoming *tinc;
 	struct sk_buff *skb;
 	int ret = 0;

 	if (!iov_iter_count(to))
 		goto out;

 	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);

 	skb_queue_walk(&tinc->ti_skb_list, skb) {
 		unsigned long to_copy, skb_off;
 		for (skb_off = 0; skb_off < skb->len; skb_off += to_copy) {
 			to_copy = iov_iter_count(to);
 			to_copy = min(to_copy, skb->len - skb_off);

 			if (skb_copy_datagram_iter(skb, skb_off, to, to_copy))
 				return -EFAULT;

 			rds_stats_add(s_copy_to_user, to_copy);
 			ret += to_copy;

 			if (!iov_iter_count(to))
 				goto out;
 		}
 	}
 out:
 	return ret;
 }

 /*
  * We have a series of skbs that have fragmented pieces of the congestion
  * bitmap.  They must add up to the exact size of the congestion bitmap.  We
  * use the skb helpers to copy those into the pages that make up the in-memory
  * congestion bitmap for the remote address of this connection.  We then tell
  * the congestion core that the bitmap has been changed so that it can wake up
  * sleepers.
  *
  * This is racing with sending paths which are using test_bit to see if the
  * bitmap indicates that their recipient is congested.
  */

 static void rds_tcp_cong_recv(struct rds_connection *conn,
 			      struct rds_tcp_incoming *tinc)
 {
 	struct sk_buff *skb;
 	unsigned int to_copy, skb_off;
 	unsigned int map_off;
 	unsigned int map_page;
 	struct rds_cong_map *map;
 	int ret;

 	/* catch completely corrupt packets */
 	if (be32_to_cpu(tinc->ti_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
 		return;

 	map_page = 0;
 	map_off = 0;
 	map = conn->c_fcong;

 	skb_queue_walk(&tinc->ti_skb_list, skb) {
 		skb_off = 0;
 		while (skb_off < skb->len) {
 			to_copy = min_t(unsigned int, PAGE_SIZE - map_off,
 					skb->len - skb_off);

 			BUG_ON(map_page >= RDS_CONG_MAP_PAGES);

 			/* only returns 0 or -error */
 			ret = skb_copy_bits(skb, skb_off,
 				(void *)map->m_page_addrs[map_page] + map_off,
 				to_copy);
 			BUG_ON(ret != 0);

 			skb_off += to_copy;
 			map_off += to_copy;
 			if (map_off == PAGE_SIZE) {
 				map_off = 0;
 				map_page++;
 			}
 		}
 	}

 	rds_cong_map_updated(map, ~(u64) 0);
 }

 struct rds_tcp_desc_arg {
 	struct rds_conn_path *conn_path;
 	gfp_t gfp;
 };

 static int rds_tcp_data_recv(read_descriptor_t *desc, struct sk_buff *skb,
 			     unsigned int offset, size_t len)
 {
 	struct rds_tcp_desc_arg *arg = desc->arg.data;
 	struct rds_conn_path *cp = arg->conn_path;
 	struct rds_tcp_connection *tc = cp->cp_transport_data;
 	struct rds_tcp_incoming *tinc = tc->t_tinc;
 	struct sk_buff *clone;
 	size_t left = len, to_copy;

 	rdsdebug("tcp data tc %p skb %p offset %u len %zu\n", tc, skb, offset,
 		 len);

 	/*
 	 * tcp_read_sock() interprets partial progress as an indication to stop
 	 * processing.
 	 */
 	while (left) {
 		if (!tinc) {
 			tinc = kmem_cache_alloc(rds_tcp_incoming_slab,
 						arg->gfp);
 			if (!tinc) {
 				desc->error = -ENOMEM;
 				goto out;
 			}
 			tc->t_tinc = tinc;
 			rdsdebug("alloced tinc %p\n", tinc);
 			rds_inc_path_init(&tinc->ti_inc, cp,
 					  &cp->cp_conn->c_faddr);
 			tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] =
 					local_clock();

 			/*
 			 * XXX * we might be able to use the __ variants when
 			 * we've already serialized at a higher level.
 			 */
 			skb_queue_head_init(&tinc->ti_skb_list);
 		}

 		if (left && tc->t_tinc_hdr_rem) {
 			to_copy = min(tc->t_tinc_hdr_rem, left);
 			rdsdebug("copying %zu header from skb %p\n", to_copy,
 				 skb);
 			skb_copy_bits(skb, offset,
 				      (char *)&tinc->ti_inc.i_hdr +
 						sizeof(struct rds_header) -
 						tc->t_tinc_hdr_rem,
 				      to_copy);
 			tc->t_tinc_hdr_rem -= to_copy;
 			left -= to_copy;
 			offset += to_copy;

 			if (tc->t_tinc_hdr_rem == 0) {
 				/* could be 0 for a 0 len message */
 				tc->t_tinc_data_rem =
 					be32_to_cpu(tinc->ti_inc.i_hdr.h_len);
 				tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_START] =
 					local_clock();
 			}
 		}

 		if (left && tc->t_tinc_data_rem) {
 			to_copy = min(tc->t_tinc_data_rem, left);

 			clone = pskb_extract(skb, offset, to_copy, arg->gfp);
 			if (!clone) {
 				desc->error = -ENOMEM;
 				goto out;
 			}

 			skb_queue_tail(&tinc->ti_skb_list, clone);

 			rdsdebug("skb %p data %p len %d off %u to_copy %zu -> "
 				 "clone %p data %p len %d\n",
 				 skb, skb->data, skb->len, offset, to_copy,
 				 clone, clone->data, clone->len);

 			tc->t_tinc_data_rem -= to_copy;
 			left -= to_copy;
 			offset += to_copy;
 		}

 		if (tc->t_tinc_hdr_rem == 0 && tc->t_tinc_data_rem == 0) {
 			struct rds_connection *conn = cp->cp_conn;

 			if (tinc->ti_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
 				rds_tcp_cong_recv(conn, tinc);
 			else
 				rds_recv_incoming(conn, &conn->c_faddr,
 						  &conn->c_laddr,
 						  &tinc->ti_inc,
 						  arg->gfp);

 			tc->t_tinc_hdr_rem = sizeof(struct rds_header);
 			tc->t_tinc_data_rem = 0;
 			tc->t_tinc = NULL;
 			rds_inc_put(&tinc->ti_inc);
 			tinc = NULL;
 		}
 	}
 out:
 	rdsdebug("returning len %zu left %zu skb len %d rx queue depth %d\n",
 		 len, left, skb->len,
 		 skb_queue_len(&tc->t_sock->sk->sk_receive_queue));
 	return len - left;
 }

 /* the caller has to hold the sock lock */
 static int rds_tcp_read_sock(struct rds_conn_path *cp, gfp_t gfp)
 {
 	struct rds_tcp_connection *tc = cp->cp_transport_data;
 	struct socket *sock = tc->t_sock;
 	read_descriptor_t desc;
 	struct rds_tcp_desc_arg arg;

 	/* It's like glib in the kernel! */
 	arg.conn_path = cp;
 	arg.gfp = gfp;
 	desc.arg.data = &arg;
 	desc.error = 0;
 	desc.count = 1; /* give more than one skb per call */

 	tcp_read_sock(sock->sk, &desc, rds_tcp_data_recv);
 	rdsdebug("tcp_read_sock for tc %p gfp 0x%x returned %d\n", tc, gfp,
 		 desc.error);

 	return desc.error;
 }

 /*
  * We hold the sock lock to serialize our rds_tcp_recv->tcp_read_sock from
  * data_ready.
  *
  * if we fail to allocate we're in trouble.. blindly wait some time before
  * trying again to see if the VM can free up something for us.
  */
 int rds_tcp_recv_path(struct rds_conn_path *cp)
 {
 	struct rds_tcp_connection *tc = cp->cp_transport_data;
 	struct socket *sock = tc->t_sock;
 	int ret = 0;

 	rdsdebug("recv worker path [%d] tc %p sock %p\n",
 		 cp->cp_index, tc, sock);

 	lock_sock(sock->sk);
 	ret = rds_tcp_read_sock(cp, GFP_KERNEL);
 	release_sock(sock->sk);

 	return ret;
 }

 void rds_tcp_data_ready(struct sock *sk)
 {
 	void (*ready)(struct sock *sk);
 	struct rds_conn_path *cp;
 	struct rds_tcp_connection *tc;

 	rdsdebug("data ready sk %p\n", sk);

 	read_lock_bh(&sk->sk_callback_lock);
 	cp = sk->sk_user_data;
 	if (!cp) { /* check for teardown race */
 		ready = sk->sk_data_ready;
 		goto out;
 	}

 	tc = cp->cp_transport_data;
 	ready = tc->t_orig_data_ready;
 	rds_tcp_stats_inc(s_tcp_data_ready_calls);

 	if (rds_tcp_read_sock(cp, GFP_ATOMIC) == -ENOMEM) {
 		rcu_read_lock();
 		if (!rds_destroy_pending(cp->cp_conn))
 			queue_delayed_work(rds_wq, &cp->cp_recv_w, 0);
 		rcu_read_unlock();
 	}
 out:
 	read_unlock_bh(&sk->sk_callback_lock);
 	ready(sk);
 }

 int rds_tcp_recv_init(void)
 {
 	rds_tcp_incoming_slab = kmem_cache_create("rds_tcp_incoming",
 					sizeof(struct rds_tcp_incoming),
 					0, 0, NULL);
 	if (!rds_tcp_incoming_slab)
 		return -ENOMEM;
 	return 0;
 }

 void rds_tcp_recv_exit(void)
 {
 	kmem_cache_destroy(rds_tcp_incoming_slab);
 }
	/*
	* Copyright (c) 2006, 2017 Oracle and/or its affiliates. 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/kernel.h>
	#include <linux/slab.h>
	#include <net/tcp.h>

	#include "rds.h"
	#include "tcp.h"

	static struct kmem_cache *rds_tcp_incoming_slab;

	static void rds_tcp_inc_purge(struct rds_incoming *inc)
	{
	struct rds_tcp_incoming *tinc;
	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
	rdsdebug("purging tinc %p inc %p\n", tinc, inc);
	skb_queue_purge(&tinc->ti_skb_list);
	}

	void rds_tcp_inc_free(struct rds_incoming *inc)
	{
	struct rds_tcp_incoming *tinc;
	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
	rds_tcp_inc_purge(inc);
	rdsdebug("freeing tinc %p inc %p\n", tinc, inc);
	kmem_cache_free(rds_tcp_incoming_slab, tinc);
	}

	/*
	* this is pretty lame, but, whatever.
	*/
	int rds_tcp_inc_copy_to_user(struct rds_incoming inc, struct iov_iter to)
	{
	struct rds_tcp_incoming *tinc;
	struct sk_buff *skb;
	int ret = 0;

	if (!iov_iter_count(to))
	goto out;

	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);

	skb_queue_walk(&tinc->ti_skb_list, skb) {
	unsigned long to_copy, skb_off;
	for (skb_off = 0; skb_off < skb->len; skb_off += to_copy) {
	to_copy = iov_iter_count(to);
	to_copy = min(to_copy, skb->len - skb_off);

	if (skb_copy_datagram_iter(skb, skb_off, to, to_copy))
	return -EFAULT;

	rds_stats_add(s_copy_to_user, to_copy);
	ret += to_copy;

	if (!iov_iter_count(to))
	goto out;
	}
	}
	out:
	return ret;
	}

	/*
	* We have a series of skbs that have fragmented pieces of the congestion
	* bitmap. They must add up to the exact size of the congestion bitmap. We
	* use the skb helpers to copy those into the pages that make up the in-memory
	* congestion bitmap for the remote address of this connection. We then tell
	* the congestion core that the bitmap has been changed so that it can wake up
	* sleepers.
	*
	* This is racing with sending paths which are using test_bit to see if the
	* bitmap indicates that their recipient is congested.
	*/

	static void rds_tcp_cong_recv(struct rds_connection *conn,
	struct rds_tcp_incoming *tinc)
	{
	struct sk_buff *skb;
	unsigned int to_copy, skb_off;
	unsigned int map_off;
	unsigned int map_page;
	struct rds_cong_map *map;
	int ret;

	/* catch completely corrupt packets */
	if (be32_to_cpu(tinc->ti_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
	return;

	map_page = 0;
	map_off = 0;
	map = conn->c_fcong;

	skb_queue_walk(&tinc->ti_skb_list, skb) {
	skb_off = 0;
	while (skb_off < skb->len) {
	to_copy = min_t(unsigned int, PAGE_SIZE - map_off,
	skb->len - skb_off);

	BUG_ON(map_page >= RDS_CONG_MAP_PAGES);

	/* only returns 0 or -error */
	ret = skb_copy_bits(skb, skb_off,
	(void *)map->m_page_addrs[map_page] + map_off,
	to_copy);
	BUG_ON(ret != 0);

	skb_off += to_copy;
	map_off += to_copy;
	if (map_off == PAGE_SIZE) {
	map_off = 0;
	map_page++;
	}
	}
	}

	rds_cong_map_updated(map, ~(u64) 0);
	}

	struct rds_tcp_desc_arg {
	struct rds_conn_path *conn_path;
	gfp_t gfp;
	};

	static int rds_tcp_data_recv(read_descriptor_t desc, struct sk_buff skb,
	unsigned int offset, size_t len)
	{
	struct rds_tcp_desc_arg *arg = desc->arg.data;
	struct rds_conn_path *cp = arg->conn_path;
	struct rds_tcp_connection *tc = cp->cp_transport_data;
	struct rds_tcp_incoming *tinc = tc->t_tinc;
	struct sk_buff *clone;
	size_t left = len, to_copy;

	rdsdebug("tcp data tc %p skb %p offset %u len %zu\n", tc, skb, offset,
	len);

	/*
	* tcp_read_sock() interprets partial progress as an indication to stop
	* processing.
	*/
	while (left) {
	if (!tinc) {
	tinc = kmem_cache_alloc(rds_tcp_incoming_slab,
	arg->gfp);
	if (!tinc) {
	desc->error = -ENOMEM;
	goto out;
	}
	tc->t_tinc = tinc;
	rdsdebug("alloced tinc %p\n", tinc);
	rds_inc_path_init(&tinc->ti_inc, cp,
	&cp->cp_conn->c_faddr);
	tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] =
	local_clock();

	/*
	* XXX * we might be able to use the __ variants when
	* we've already serialized at a higher level.
	*/
	skb_queue_head_init(&tinc->ti_skb_list);
	}

	if (left && tc->t_tinc_hdr_rem) {
	to_copy = min(tc->t_tinc_hdr_rem, left);
	rdsdebug("copying %zu header from skb %p\n", to_copy,
	skb);
	skb_copy_bits(skb, offset,
	(char *)&tinc->ti_inc.i_hdr +
	sizeof(struct rds_header) -
	tc->t_tinc_hdr_rem,
	to_copy);
	tc->t_tinc_hdr_rem -= to_copy;
	left -= to_copy;
	offset += to_copy;

	if (tc->t_tinc_hdr_rem == 0) {
	/* could be 0 for a 0 len message */
	tc->t_tinc_data_rem =
	be32_to_cpu(tinc->ti_inc.i_hdr.h_len);
	tinc->ti_inc.i_rx_lat_trace[RDS_MSG_RX_START] =
	local_clock();
	}
	}

	if (left && tc->t_tinc_data_rem) {
	to_copy = min(tc->t_tinc_data_rem, left);

	clone = pskb_extract(skb, offset, to_copy, arg->gfp);
	if (!clone) {
	desc->error = -ENOMEM;
	goto out;
	}

	skb_queue_tail(&tinc->ti_skb_list, clone);

	rdsdebug("skb %p data %p len %d off %u to_copy %zu -> "
	"clone %p data %p len %d\n",
	skb, skb->data, skb->len, offset, to_copy,
	clone, clone->data, clone->len);

	tc->t_tinc_data_rem -= to_copy;
	left -= to_copy;
	offset += to_copy;
	}

	if (tc->t_tinc_hdr_rem == 0 && tc->t_tinc_data_rem == 0) {
	struct rds_connection *conn = cp->cp_conn;

	if (tinc->ti_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
	rds_tcp_cong_recv(conn, tinc);
	else
	rds_recv_incoming(conn, &conn->c_faddr,
	&conn->c_laddr,
	&tinc->ti_inc,
	arg->gfp);

	tc->t_tinc_hdr_rem = sizeof(struct rds_header);
	tc->t_tinc_data_rem = 0;
	tc->t_tinc = NULL;
	rds_inc_put(&tinc->ti_inc);
	tinc = NULL;
	}
	}
	out:
	rdsdebug("returning len %zu left %zu skb len %d rx queue depth %d\n",
	len, left, skb->len,
	skb_queue_len(&tc->t_sock->sk->sk_receive_queue));
	return len - left;
	}

	/* the caller has to hold the sock lock */
	static int rds_tcp_read_sock(struct rds_conn_path *cp, gfp_t gfp)
	{
	struct rds_tcp_connection *tc = cp->cp_transport_data;
	struct socket *sock = tc->t_sock;
	read_descriptor_t desc;
	struct rds_tcp_desc_arg arg;

	/* It's like glib in the kernel! */
	arg.conn_path = cp;
	arg.gfp = gfp;
	desc.arg.data = &arg;
	desc.error = 0;
	desc.count = 1; /* give more than one skb per call */

	tcp_read_sock(sock->sk, &desc, rds_tcp_data_recv);
	rdsdebug("tcp_read_sock for tc %p gfp 0x%x returned %d\n", tc, gfp,
	desc.error);

	return desc.error;
	}

	/*
	* We hold the sock lock to serialize our rds_tcp_recv->tcp_read_sock from
	* data_ready.
	*
	* if we fail to allocate we're in trouble.. blindly wait some time before
	* trying again to see if the VM can free up something for us.
	*/
	int rds_tcp_recv_path(struct rds_conn_path *cp)
	{
	struct rds_tcp_connection *tc = cp->cp_transport_data;
	struct socket *sock = tc->t_sock;
	int ret = 0;

	rdsdebug("recv worker path [%d] tc %p sock %p\n",
	cp->cp_index, tc, sock);

	lock_sock(sock->sk);
	ret = rds_tcp_read_sock(cp, GFP_KERNEL);
	release_sock(sock->sk);

	return ret;
	}

	void rds_tcp_data_ready(struct sock *sk)
	{
	void (ready)(struct sock sk);
	struct rds_conn_path *cp;
	struct rds_tcp_connection *tc;

	rdsdebug("data ready sk %p\n", sk);

	read_lock_bh(&sk->sk_callback_lock);
	cp = sk->sk_user_data;
	if (!cp) { /* check for teardown race */
	ready = sk->sk_data_ready;
	goto out;
	}

	tc = cp->cp_transport_data;
	ready = tc->t_orig_data_ready;
	rds_tcp_stats_inc(s_tcp_data_ready_calls);

	if (rds_tcp_read_sock(cp, GFP_ATOMIC) == -ENOMEM) {
	rcu_read_lock();
	if (!rds_destroy_pending(cp->cp_conn))
	queue_delayed_work(rds_wq, &cp->cp_recv_w, 0);
	rcu_read_unlock();
	}
	out:
	read_unlock_bh(&sk->sk_callback_lock);
	ready(sk);
	}

	int rds_tcp_recv_init(void)
	{
	rds_tcp_incoming_slab = kmem_cache_create("rds_tcp_incoming",
	sizeof(struct rds_tcp_incoming),
	0, 0, NULL);
	if (!rds_tcp_incoming_slab)
	return -ENOMEM;
	return 0;
	}

	void rds_tcp_recv_exit(void)
	{
	kmem_cache_destroy(rds_tcp_incoming_slab);
	}