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b21dd4506b
Commit a93d01f577 ("RDS: TCP: avoid bad page reference in
rds_tcp_listen_data_ready") added the function
rds_tcp_listen_sock_def_readable() to handle the case when a
partially set-up acceptor socket drops into rds_tcp_listen_data_ready().
However, if the listen socket (rtn->rds_tcp_listen_sock) is itself going
through a tear-down via rds_tcp_listen_stop(), the (*ready)() will be
null and we would hit a panic of the form
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: (null)
:
? rds_tcp_listen_data_ready+0x59/0xb0 [rds_tcp]
tcp_data_queue+0x39d/0x5b0
tcp_rcv_established+0x2e5/0x660
tcp_v4_do_rcv+0x122/0x220
tcp_v4_rcv+0x8b7/0x980
:
In the above case, it is not fatal to encounter a NULL value for
ready- we should just drop the packet and let the flush of the
acceptor thread finish gracefully.
In general, the tear-down sequence for listen() and accept() socket
that is ensured by this commit is:
rtn->rds_tcp_listen_sock = NULL; /* prevent any new accepts */
In rds_tcp_listen_stop():
serialize with, and prevent, further callbacks using lock_sock()
flush rds_wq
flush acceptor workq
sock_release(listen socket)
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
97 lines
3.0 KiB
C
97 lines
3.0 KiB
C
#ifndef _RDS_TCP_H
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#define _RDS_TCP_H
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#define RDS_TCP_PORT 16385
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struct rds_tcp_incoming {
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struct rds_incoming ti_inc;
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struct sk_buff_head ti_skb_list;
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};
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struct rds_tcp_connection {
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struct list_head t_tcp_node;
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struct rds_conn_path *t_cpath;
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/* t_conn_path_lock synchronizes the connection establishment between
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* rds_tcp_accept_one and rds_tcp_conn_path_connect
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*/
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struct mutex t_conn_path_lock;
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struct socket *t_sock;
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void *t_orig_write_space;
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void *t_orig_data_ready;
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void *t_orig_state_change;
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struct rds_tcp_incoming *t_tinc;
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size_t t_tinc_hdr_rem;
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size_t t_tinc_data_rem;
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/* XXX error report? */
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struct work_struct t_conn_w;
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struct work_struct t_send_w;
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struct work_struct t_down_w;
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struct work_struct t_recv_w;
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/* for info exporting only */
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struct list_head t_list_item;
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u32 t_last_sent_nxt;
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u32 t_last_expected_una;
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u32 t_last_seen_una;
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};
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struct rds_tcp_statistics {
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uint64_t s_tcp_data_ready_calls;
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uint64_t s_tcp_write_space_calls;
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uint64_t s_tcp_sndbuf_full;
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uint64_t s_tcp_connect_raced;
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uint64_t s_tcp_listen_closed_stale;
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};
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/* tcp.c */
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void rds_tcp_tune(struct socket *sock);
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void rds_tcp_nonagle(struct socket *sock);
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void rds_tcp_set_callbacks(struct socket *sock, struct rds_conn_path *cp);
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void rds_tcp_reset_callbacks(struct socket *sock, struct rds_conn_path *cp);
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void rds_tcp_restore_callbacks(struct socket *sock,
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struct rds_tcp_connection *tc);
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u32 rds_tcp_snd_nxt(struct rds_tcp_connection *tc);
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u32 rds_tcp_snd_una(struct rds_tcp_connection *tc);
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u64 rds_tcp_map_seq(struct rds_tcp_connection *tc, u32 seq);
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extern struct rds_transport rds_tcp_transport;
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void rds_tcp_accept_work(struct sock *sk);
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/* tcp_connect.c */
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int rds_tcp_conn_path_connect(struct rds_conn_path *cp);
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void rds_tcp_conn_path_shutdown(struct rds_conn_path *conn);
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void rds_tcp_state_change(struct sock *sk);
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/* tcp_listen.c */
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struct socket *rds_tcp_listen_init(struct net *);
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void rds_tcp_listen_stop(struct socket *sock, struct work_struct *acceptor);
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void rds_tcp_listen_data_ready(struct sock *sk);
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int rds_tcp_accept_one(struct socket *sock);
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int rds_tcp_keepalive(struct socket *sock);
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void *rds_tcp_listen_sock_def_readable(struct net *net);
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/* tcp_recv.c */
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int rds_tcp_recv_init(void);
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void rds_tcp_recv_exit(void);
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void rds_tcp_data_ready(struct sock *sk);
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int rds_tcp_recv_path(struct rds_conn_path *cp);
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void rds_tcp_inc_free(struct rds_incoming *inc);
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int rds_tcp_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to);
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/* tcp_send.c */
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void rds_tcp_xmit_path_prepare(struct rds_conn_path *cp);
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void rds_tcp_xmit_path_complete(struct rds_conn_path *cp);
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int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
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unsigned int hdr_off, unsigned int sg, unsigned int off);
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void rds_tcp_write_space(struct sock *sk);
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/* tcp_stats.c */
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DECLARE_PER_CPU(struct rds_tcp_statistics, rds_tcp_stats);
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#define rds_tcp_stats_inc(member) rds_stats_inc_which(rds_tcp_stats, member)
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unsigned int rds_tcp_stats_info_copy(struct rds_info_iterator *iter,
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unsigned int avail);
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#endif
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