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![Dust Li](/assets/img/avatar_default.png)
A crash occurs when smc_cdc_tx_handler() tries to access smc_sock
but smc_release() has already freed it.
[ 4570.695099] BUG: unable to handle page fault for address: 000000002eae9e88
[ 4570.696048] #PF: supervisor write access in kernel mode
[ 4570.696728] #PF: error_code(0x0002) - not-present page
[ 4570.697401] PGD 0 P4D 0
[ 4570.697716] Oops: 0002 [#1] PREEMPT SMP NOPTI
[ 4570.698228] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.16.0-rc4+ #111
[ 4570.699013] Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 8c24b4c 04/0
[ 4570.699933] RIP: 0010:_raw_spin_lock+0x1a/0x30
<...>
[ 4570.711446] Call Trace:
[ 4570.711746] <IRQ>
[ 4570.711992] smc_cdc_tx_handler+0x41/0xc0
[ 4570.712470] smc_wr_tx_tasklet_fn+0x213/0x560
[ 4570.712981] ? smc_cdc_tx_dismisser+0x10/0x10
[ 4570.713489] tasklet_action_common.isra.17+0x66/0x140
[ 4570.714083] __do_softirq+0x123/0x2f4
[ 4570.714521] irq_exit_rcu+0xc4/0xf0
[ 4570.714934] common_interrupt+0xba/0xe0
Though smc_cdc_tx_handler() checked the existence of smc connection,
smc_release() may have already dismissed and released the smc socket
before smc_cdc_tx_handler() further visits it.
smc_cdc_tx_handler() |smc_release()
if (!conn) |
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|smc_cdc_tx_dismiss_slots()
| smc_cdc_tx_dismisser()
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|sock_put(&smc->sk) <- last sock_put,
| smc_sock freed
bh_lock_sock(&smc->sk) (panic) |
To make sure we won't receive any CDC messages after we free the
smc_sock, add a refcount on the smc_connection for inflight CDC
message(posted to the QP but haven't received related CQE), and
don't release the smc_connection until all the inflight CDC messages
haven been done, for both success or failed ones.
Using refcount on CDC messages brings another problem: when the link
is going to be destroyed, smcr_link_clear() will reset the QP, which
then remove all the pending CQEs related to the QP in the CQ. To make
sure all the CQEs will always come back so the refcount on the
smc_connection can always reach 0, smc_ib_modify_qp_reset() was replaced
by smc_ib_modify_qp_error().
And remove the timeout in smc_wr_tx_wait_no_pending_sends() since we
need to wait for all pending WQEs done, or we may encounter use-after-
free when handling CQEs.
For IB device removal routine, we need to wait for all the QPs on that
device been destroyed before we can destroy CQs on the device, or
the refcount on smc_connection won't reach 0 and smc_sock cannot be
released.
Fixes: 5f08318f61
("smc: connection data control (CDC)")
Reported-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
316 lines
9 KiB
C
316 lines
9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Shared Memory Communications over RDMA (SMC-R) and RoCE
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*
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* Definitions for the SMC module (socket related)
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*
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* Copyright IBM Corp. 2016
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*
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* Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
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*/
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#ifndef __SMC_H
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#define __SMC_H
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#include <linux/socket.h>
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#include <linux/types.h>
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#include <linux/compiler.h> /* __aligned */
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#include <net/sock.h>
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#include "smc_ib.h"
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#define SMC_V1 1 /* SMC version V1 */
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#define SMC_V2 2 /* SMC version V2 */
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#define SMC_RELEASE 0
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#define SMCPROTO_SMC 0 /* SMC protocol, IPv4 */
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#define SMCPROTO_SMC6 1 /* SMC protocol, IPv6 */
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#define SMC_MAX_ISM_DEVS 8 /* max # of proposed non-native ISM
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* devices
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*/
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extern struct proto smc_proto;
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extern struct proto smc_proto6;
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#ifdef ATOMIC64_INIT
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#define KERNEL_HAS_ATOMIC64
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#endif
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enum smc_state { /* possible states of an SMC socket */
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SMC_ACTIVE = 1,
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SMC_INIT = 2,
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SMC_CLOSED = 7,
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SMC_LISTEN = 10,
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/* normal close */
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SMC_PEERCLOSEWAIT1 = 20,
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SMC_PEERCLOSEWAIT2 = 21,
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SMC_APPFINCLOSEWAIT = 24,
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SMC_APPCLOSEWAIT1 = 22,
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SMC_APPCLOSEWAIT2 = 23,
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SMC_PEERFINCLOSEWAIT = 25,
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/* abnormal close */
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SMC_PEERABORTWAIT = 26,
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SMC_PROCESSABORT = 27,
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};
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struct smc_link_group;
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struct smc_wr_rx_hdr { /* common prefix part of LLC and CDC to demultiplex */
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union {
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u8 type;
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#if defined(__BIG_ENDIAN_BITFIELD)
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struct {
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u8 llc_version:4,
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llc_type:4;
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};
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#elif defined(__LITTLE_ENDIAN_BITFIELD)
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struct {
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u8 llc_type:4,
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llc_version:4;
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};
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#endif
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};
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} __aligned(1);
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struct smc_cdc_conn_state_flags {
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#if defined(__BIG_ENDIAN_BITFIELD)
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u8 peer_done_writing : 1; /* Sending done indicator */
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u8 peer_conn_closed : 1; /* Peer connection closed indicator */
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u8 peer_conn_abort : 1; /* Abnormal close indicator */
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u8 reserved : 5;
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#elif defined(__LITTLE_ENDIAN_BITFIELD)
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u8 reserved : 5;
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u8 peer_conn_abort : 1;
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u8 peer_conn_closed : 1;
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u8 peer_done_writing : 1;
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#endif
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};
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struct smc_cdc_producer_flags {
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#if defined(__BIG_ENDIAN_BITFIELD)
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u8 write_blocked : 1; /* Writing Blocked, no rx buf space */
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u8 urg_data_pending : 1; /* Urgent Data Pending */
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u8 urg_data_present : 1; /* Urgent Data Present */
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u8 cons_curs_upd_req : 1; /* cursor update requested */
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u8 failover_validation : 1;/* message replay due to failover */
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u8 reserved : 3;
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#elif defined(__LITTLE_ENDIAN_BITFIELD)
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u8 reserved : 3;
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u8 failover_validation : 1;
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u8 cons_curs_upd_req : 1;
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u8 urg_data_present : 1;
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u8 urg_data_pending : 1;
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u8 write_blocked : 1;
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#endif
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};
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/* in host byte order */
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union smc_host_cursor { /* SMC cursor - an offset in an RMBE */
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struct {
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u16 reserved;
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u16 wrap; /* window wrap sequence number */
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u32 count; /* cursor (= offset) part */
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};
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#ifdef KERNEL_HAS_ATOMIC64
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atomic64_t acurs; /* for atomic processing */
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#else
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u64 acurs; /* for atomic processing */
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#endif
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} __aligned(8);
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/* in host byte order, except for flag bitfields in network byte order */
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struct smc_host_cdc_msg { /* Connection Data Control message */
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struct smc_wr_rx_hdr common; /* .type = 0xFE */
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u8 len; /* length = 44 */
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u16 seqno; /* connection seq # */
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u32 token; /* alert_token */
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union smc_host_cursor prod; /* producer cursor */
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union smc_host_cursor cons; /* consumer cursor,
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* piggy backed "ack"
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*/
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struct smc_cdc_producer_flags prod_flags; /* conn. tx/rx status */
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struct smc_cdc_conn_state_flags conn_state_flags; /* peer conn. status*/
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u8 reserved[18];
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} __aligned(8);
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enum smc_urg_state {
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SMC_URG_VALID = 1, /* data present */
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SMC_URG_NOTYET = 2, /* data pending */
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SMC_URG_READ = 3, /* data was already read */
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};
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struct smc_connection {
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struct rb_node alert_node;
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struct smc_link_group *lgr; /* link group of connection */
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struct smc_link *lnk; /* assigned SMC-R link */
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u32 alert_token_local; /* unique conn. id */
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u8 peer_rmbe_idx; /* from tcp handshake */
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int peer_rmbe_size; /* size of peer rx buffer */
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atomic_t peer_rmbe_space;/* remaining free bytes in peer
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* rmbe
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*/
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int rtoken_idx; /* idx to peer RMB rkey/addr */
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struct smc_buf_desc *sndbuf_desc; /* send buffer descriptor */
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struct smc_buf_desc *rmb_desc; /* RMBE descriptor */
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int rmbe_size_short;/* compressed notation */
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int rmbe_update_limit;
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/* lower limit for consumer
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* cursor update
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*/
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struct smc_host_cdc_msg local_tx_ctrl; /* host byte order staging
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* buffer for CDC msg send
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* .prod cf. TCP snd_nxt
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* .cons cf. TCP sends ack
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*/
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union smc_host_cursor local_tx_ctrl_fin;
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/* prod crsr - confirmed by peer
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*/
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union smc_host_cursor tx_curs_prep; /* tx - prepared data
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* snd_max..wmem_alloc
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*/
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union smc_host_cursor tx_curs_sent; /* tx - sent data
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* snd_nxt ?
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*/
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union smc_host_cursor tx_curs_fin; /* tx - confirmed by peer
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* snd-wnd-begin ?
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*/
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atomic_t sndbuf_space; /* remaining space in sndbuf */
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u16 tx_cdc_seq; /* sequence # for CDC send */
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u16 tx_cdc_seq_fin; /* sequence # - tx completed */
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spinlock_t send_lock; /* protect wr_sends */
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atomic_t cdc_pend_tx_wr; /* number of pending tx CDC wqe
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* - inc when post wqe,
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* - dec on polled tx cqe
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*/
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wait_queue_head_t cdc_pend_tx_wq; /* wakeup on no cdc_pend_tx_wr*/
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struct delayed_work tx_work; /* retry of smc_cdc_msg_send */
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u32 tx_off; /* base offset in peer rmb */
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struct smc_host_cdc_msg local_rx_ctrl; /* filled during event_handl.
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* .prod cf. TCP rcv_nxt
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* .cons cf. TCP snd_una
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*/
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union smc_host_cursor rx_curs_confirmed; /* confirmed to peer
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* source of snd_una ?
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*/
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union smc_host_cursor urg_curs; /* points at urgent byte */
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enum smc_urg_state urg_state;
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bool urg_tx_pend; /* urgent data staged */
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bool urg_rx_skip_pend;
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/* indicate urgent oob data
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* read, but previous regular
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* data still pending
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*/
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char urg_rx_byte; /* urgent byte */
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atomic_t bytes_to_rcv; /* arrived data,
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* not yet received
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*/
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atomic_t splice_pending; /* number of spliced bytes
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* pending processing
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*/
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#ifndef KERNEL_HAS_ATOMIC64
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spinlock_t acurs_lock; /* protect cursors */
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#endif
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struct work_struct close_work; /* peer sent some closing */
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struct work_struct abort_work; /* abort the connection */
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struct tasklet_struct rx_tsklet; /* Receiver tasklet for SMC-D */
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u8 rx_off; /* receive offset:
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* 0 for SMC-R, 32 for SMC-D
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*/
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u64 peer_token; /* SMC-D token of peer */
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u8 killed : 1; /* abnormal termination */
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u8 out_of_sync : 1; /* out of sync with peer */
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};
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struct smc_sock { /* smc sock container */
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struct sock sk;
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struct socket *clcsock; /* internal tcp socket */
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void (*clcsk_data_ready)(struct sock *sk);
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/* original data_ready fct. **/
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struct smc_connection conn; /* smc connection */
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struct smc_sock *listen_smc; /* listen parent */
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struct work_struct connect_work; /* handle non-blocking connect*/
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struct work_struct tcp_listen_work;/* handle tcp socket accepts */
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struct work_struct smc_listen_work;/* prepare new accept socket */
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struct list_head accept_q; /* sockets to be accepted */
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spinlock_t accept_q_lock; /* protects accept_q */
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bool use_fallback; /* fallback to tcp */
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int fallback_rsn; /* reason for fallback */
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u32 peer_diagnosis; /* decline reason from peer */
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int sockopt_defer_accept;
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/* sockopt TCP_DEFER_ACCEPT
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* value
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*/
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u8 wait_close_tx_prepared : 1;
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/* shutdown wr or close
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* started, waiting for unsent
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* data to be sent
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*/
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u8 connect_nonblock : 1;
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/* non-blocking connect in
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* flight
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*/
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struct mutex clcsock_release_lock;
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/* protects clcsock of a listen
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* socket
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* */
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};
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static inline struct smc_sock *smc_sk(const struct sock *sk)
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{
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return (struct smc_sock *)sk;
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}
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extern struct workqueue_struct *smc_hs_wq; /* wq for handshake work */
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extern struct workqueue_struct *smc_close_wq; /* wq for close work */
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#define SMC_SYSTEMID_LEN 8
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extern u8 local_systemid[SMC_SYSTEMID_LEN]; /* unique system identifier */
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#define ntohll(x) be64_to_cpu(x)
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#define htonll(x) cpu_to_be64(x)
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/* convert an u32 value into network byte order, store it into a 3 byte field */
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static inline void hton24(u8 *net, u32 host)
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{
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__be32 t;
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t = cpu_to_be32(host);
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memcpy(net, ((u8 *)&t) + 1, 3);
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}
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/* convert a received 3 byte field into host byte order*/
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static inline u32 ntoh24(u8 *net)
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{
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__be32 t = 0;
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memcpy(((u8 *)&t) + 1, net, 3);
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return be32_to_cpu(t);
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}
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#ifdef CONFIG_XFRM
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static inline bool using_ipsec(struct smc_sock *smc)
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{
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return (smc->clcsock->sk->sk_policy[0] ||
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smc->clcsock->sk->sk_policy[1]) ? true : false;
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}
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#else
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static inline bool using_ipsec(struct smc_sock *smc)
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{
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return false;
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}
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#endif
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struct smc_gidlist;
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struct sock *smc_accept_dequeue(struct sock *parent, struct socket *new_sock);
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void smc_close_non_accepted(struct sock *sk);
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void smc_fill_gid_list(struct smc_link_group *lgr,
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struct smc_gidlist *gidlist,
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struct smc_ib_device *known_dev, u8 *known_gid);
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#endif /* __SMC_H */
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