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![Andy Grover](/assets/img/avatar_default.png)
This code allows RDS to be tunneled over a TCP connection. RDMA operations are disabled when using TCP transport, but this frees RDS from the IB/RDMA stack dependency, and allows it to be used with standard Ethernet adapters, or in a VM. Signed-off-by: Andy Grover <andy.grover@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
356 lines
9.4 KiB
C
356 lines
9.4 KiB
C
/*
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* Copyright (c) 2006 Oracle. All rights reserved.
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the
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* OpenIB.org BSD license below:
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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*/
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#include <linux/kernel.h>
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#include <net/tcp.h>
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#include "rds.h"
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#include "tcp.h"
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static struct kmem_cache *rds_tcp_incoming_slab;
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void rds_tcp_inc_purge(struct rds_incoming *inc)
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{
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struct rds_tcp_incoming *tinc;
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tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
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rdsdebug("purging tinc %p inc %p\n", tinc, inc);
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skb_queue_purge(&tinc->ti_skb_list);
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}
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void rds_tcp_inc_free(struct rds_incoming *inc)
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{
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struct rds_tcp_incoming *tinc;
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tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
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rds_tcp_inc_purge(inc);
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rdsdebug("freeing tinc %p inc %p\n", tinc, inc);
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kmem_cache_free(rds_tcp_incoming_slab, tinc);
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}
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/*
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* this is pretty lame, but, whatever.
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*/
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int rds_tcp_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov,
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size_t size)
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{
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struct rds_tcp_incoming *tinc;
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struct iovec *iov, tmp;
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struct sk_buff *skb;
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unsigned long to_copy, skb_off;
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int ret = 0;
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if (size == 0)
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goto out;
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tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
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iov = first_iov;
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tmp = *iov;
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skb_queue_walk(&tinc->ti_skb_list, skb) {
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skb_off = 0;
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while (skb_off < skb->len) {
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while (tmp.iov_len == 0) {
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iov++;
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tmp = *iov;
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}
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to_copy = min(tmp.iov_len, size);
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to_copy = min(to_copy, skb->len - skb_off);
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rdsdebug("ret %d size %zu skb %p skb_off %lu "
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"skblen %d iov_base %p iov_len %zu cpy %lu\n",
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ret, size, skb, skb_off, skb->len,
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tmp.iov_base, tmp.iov_len, to_copy);
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/* modifies tmp as it copies */
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if (skb_copy_datagram_iovec(skb, skb_off, &tmp,
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to_copy)) {
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ret = -EFAULT;
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goto out;
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}
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size -= to_copy;
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ret += to_copy;
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skb_off += to_copy;
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if (size == 0)
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goto out;
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}
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}
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out:
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return ret;
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}
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/*
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* We have a series of skbs that have fragmented pieces of the congestion
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* bitmap. They must add up to the exact size of the congestion bitmap. We
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* use the skb helpers to copy those into the pages that make up the in-memory
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* congestion bitmap for the remote address of this connection. We then tell
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* the congestion core that the bitmap has been changed so that it can wake up
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* sleepers.
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*
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* This is racing with sending paths which are using test_bit to see if the
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* bitmap indicates that their recipient is congested.
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*/
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static void rds_tcp_cong_recv(struct rds_connection *conn,
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struct rds_tcp_incoming *tinc)
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{
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struct sk_buff *skb;
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unsigned int to_copy, skb_off;
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unsigned int map_off;
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unsigned int map_page;
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struct rds_cong_map *map;
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int ret;
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/* catch completely corrupt packets */
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if (be32_to_cpu(tinc->ti_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
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return;
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map_page = 0;
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map_off = 0;
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map = conn->c_fcong;
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skb_queue_walk(&tinc->ti_skb_list, skb) {
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skb_off = 0;
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while (skb_off < skb->len) {
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to_copy = min_t(unsigned int, PAGE_SIZE - map_off,
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skb->len - skb_off);
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BUG_ON(map_page >= RDS_CONG_MAP_PAGES);
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/* only returns 0 or -error */
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ret = skb_copy_bits(skb, skb_off,
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(void *)map->m_page_addrs[map_page] + map_off,
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to_copy);
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BUG_ON(ret != 0);
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skb_off += to_copy;
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map_off += to_copy;
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if (map_off == PAGE_SIZE) {
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map_off = 0;
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map_page++;
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}
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}
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}
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rds_cong_map_updated(map, ~(u64) 0);
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}
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struct rds_tcp_desc_arg {
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struct rds_connection *conn;
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gfp_t gfp;
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enum km_type km;
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};
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static int rds_tcp_data_recv(read_descriptor_t *desc, struct sk_buff *skb,
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unsigned int offset, size_t len)
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{
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struct rds_tcp_desc_arg *arg = desc->arg.data;
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struct rds_connection *conn = arg->conn;
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struct rds_tcp_connection *tc = conn->c_transport_data;
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struct rds_tcp_incoming *tinc = tc->t_tinc;
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struct sk_buff *clone;
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size_t left = len, to_copy;
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rdsdebug("tcp data tc %p skb %p offset %u len %zu\n", tc, skb, offset,
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len);
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/*
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* tcp_read_sock() interprets partial progress as an indication to stop
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* processing.
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*/
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while (left) {
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if (tinc == NULL) {
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tinc = kmem_cache_alloc(rds_tcp_incoming_slab,
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arg->gfp);
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if (tinc == NULL) {
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desc->error = -ENOMEM;
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goto out;
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}
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tc->t_tinc = tinc;
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rdsdebug("alloced tinc %p\n", tinc);
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rds_inc_init(&tinc->ti_inc, conn, conn->c_faddr);
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/*
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* XXX * we might be able to use the __ variants when
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* we've already serialized at a higher level.
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*/
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skb_queue_head_init(&tinc->ti_skb_list);
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}
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if (left && tc->t_tinc_hdr_rem) {
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to_copy = min(tc->t_tinc_hdr_rem, left);
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rdsdebug("copying %zu header from skb %p\n", to_copy,
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skb);
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skb_copy_bits(skb, offset,
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(char *)&tinc->ti_inc.i_hdr +
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sizeof(struct rds_header) -
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tc->t_tinc_hdr_rem,
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to_copy);
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tc->t_tinc_hdr_rem -= to_copy;
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left -= to_copy;
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offset += to_copy;
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if (tc->t_tinc_hdr_rem == 0) {
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/* could be 0 for a 0 len message */
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tc->t_tinc_data_rem =
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be32_to_cpu(tinc->ti_inc.i_hdr.h_len);
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}
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}
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if (left && tc->t_tinc_data_rem) {
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clone = skb_clone(skb, arg->gfp);
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if (clone == NULL) {
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desc->error = -ENOMEM;
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goto out;
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}
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to_copy = min(tc->t_tinc_data_rem, left);
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pskb_pull(clone, offset);
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pskb_trim(clone, to_copy);
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skb_queue_tail(&tinc->ti_skb_list, clone);
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rdsdebug("skb %p data %p len %d off %u to_copy %zu -> "
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"clone %p data %p len %d\n",
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skb, skb->data, skb->len, offset, to_copy,
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clone, clone->data, clone->len);
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tc->t_tinc_data_rem -= to_copy;
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left -= to_copy;
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offset += to_copy;
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}
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if (tc->t_tinc_hdr_rem == 0 && tc->t_tinc_data_rem == 0) {
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if (tinc->ti_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
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rds_tcp_cong_recv(conn, tinc);
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else
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rds_recv_incoming(conn, conn->c_faddr,
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conn->c_laddr, &tinc->ti_inc,
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arg->gfp, arg->km);
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tc->t_tinc_hdr_rem = sizeof(struct rds_header);
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tc->t_tinc_data_rem = 0;
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tc->t_tinc = NULL;
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rds_inc_put(&tinc->ti_inc);
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tinc = NULL;
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}
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}
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out:
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rdsdebug("returning len %zu left %zu skb len %d rx queue depth %d\n",
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len, left, skb->len,
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skb_queue_len(&tc->t_sock->sk->sk_receive_queue));
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return len - left;
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}
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/* the caller has to hold the sock lock */
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int rds_tcp_read_sock(struct rds_connection *conn, gfp_t gfp, enum km_type km)
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{
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struct rds_tcp_connection *tc = conn->c_transport_data;
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struct socket *sock = tc->t_sock;
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read_descriptor_t desc;
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struct rds_tcp_desc_arg arg;
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/* It's like glib in the kernel! */
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arg.conn = conn;
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arg.gfp = gfp;
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arg.km = km;
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desc.arg.data = &arg;
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desc.error = 0;
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desc.count = 1; /* give more than one skb per call */
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tcp_read_sock(sock->sk, &desc, rds_tcp_data_recv);
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rdsdebug("tcp_read_sock for tc %p gfp 0x%x returned %d\n", tc, gfp,
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desc.error);
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return desc.error;
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}
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/*
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* We hold the sock lock to serialize our rds_tcp_recv->tcp_read_sock from
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* data_ready.
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*
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* if we fail to allocate we're in trouble.. blindly wait some time before
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* trying again to see if the VM can free up something for us.
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*/
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int rds_tcp_recv(struct rds_connection *conn)
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{
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struct rds_tcp_connection *tc = conn->c_transport_data;
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struct socket *sock = tc->t_sock;
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int ret = 0;
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rdsdebug("recv worker conn %p tc %p sock %p\n", conn, tc, sock);
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lock_sock(sock->sk);
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ret = rds_tcp_read_sock(conn, GFP_KERNEL, KM_USER0);
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release_sock(sock->sk);
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return ret;
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}
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void rds_tcp_data_ready(struct sock *sk, int bytes)
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{
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void (*ready)(struct sock *sk, int bytes);
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struct rds_connection *conn;
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struct rds_tcp_connection *tc;
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rdsdebug("data ready sk %p bytes %d\n", sk, bytes);
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read_lock(&sk->sk_callback_lock);
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conn = sk->sk_user_data;
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if (conn == NULL) { /* check for teardown race */
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ready = sk->sk_data_ready;
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goto out;
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}
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tc = conn->c_transport_data;
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ready = tc->t_orig_data_ready;
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rds_tcp_stats_inc(s_tcp_data_ready_calls);
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if (rds_tcp_read_sock(conn, GFP_ATOMIC, KM_SOFTIRQ0) == -ENOMEM)
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queue_delayed_work(rds_wq, &conn->c_recv_w, 0);
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out:
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read_unlock(&sk->sk_callback_lock);
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ready(sk, bytes);
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}
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int __init rds_tcp_recv_init(void)
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{
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rds_tcp_incoming_slab = kmem_cache_create("rds_tcp_incoming",
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sizeof(struct rds_tcp_incoming),
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0, 0, NULL);
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if (rds_tcp_incoming_slab == NULL)
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return -ENOMEM;
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return 0;
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}
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void rds_tcp_recv_exit(void)
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{
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kmem_cache_destroy(rds_tcp_incoming_slab);
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}
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