stable inclusion
from stable-v5.10.157
commit 23c03ee0eec4424a54a5619b23954d9069bac026
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7MU59

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=23c03ee0eec4424a54a5619b23954d9069bac026

--------------------------------

[ Upstream commit a0575429 ]

Move to using refcount_t rather than atomic_t for refcounts in rxrpc.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Stable-dep-of: 3bcd6c7e ("rxrpc: Fix race between conn bundle lookup and bundle removal [ZDI-CAN-15975]")
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: Nsanglipeng <sanglipeng1@jd.com>

Conflicts:
	net/rxrpc/ar-internal.h
	net/rxrpc/conn_client.c

stable inclusion
from stable-v5.10.121
commit 4790963ef433e2e248c9b5b149fdaa59aff359e5
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6CQ

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4790963ef433e2e248c9b5b149fdaa59aff359e5

--------------------------------

[ Upstream commit 9a3dedcf ]

Fix the decision on when to generate an IDLE ACK by keeping a count of the
number of packets we've received, but not yet soft-ACK'd, and the number of
packets we've processed, but not yet hard-ACK'd, rather than trying to keep
track of which DATA sequence numbers correspond to those points.

We then generate an ACK when either counter exceeds 2.  The counters are
both cleared when we transcribe the information into any sort of ACK packet
for transmission.  IDLE and DELAY ACKs are skipped if both counters are 0
(ie. no change).

Fixes: 805b21b9 ("rxrpc: Send an ACK after every few DATA packets we receive")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

stable inclusion
from stable-v5.10.110
commit 051360e51341cd17738d82c15a8226010c7cb7f6
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=051360e51341cd17738d82c15a8226010c7cb7f6

--------------------------------

commit 4a7f62f9 upstream.

The rxrpc_call struct has a timer used to handle various timed events
relating to a call.  This timer can get started from the packet input
routines that are run in softirq mode with just the RCU read lock held.
Unfortunately, because only the RCU read lock is held - and neither ref or
other lock is taken - the call can start getting destroyed at the same time
a packet comes in addressed to that call.  This causes the timer - which
was already stopped - to get restarted.  Later, the timer dispatch code may
then oops if the timer got deallocated first.

Fix this by trying to take a ref on the rxrpc_call struct and, if
successful, passing that ref along to the timer.  If the timer was already
running, the ref is discarded.

The timer completion routine can then pass the ref along to the call's work
item when it queues it.  If the timer or work item where already
queued/running, the extra ref is discarded.

Fixes: a158bdd3 ("rxrpc: Fix call timeouts")
Reported-by: NMarc Dionne <marc.dionne@auristor.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NMarc Dionne <marc.dionne@auristor.com>
Tested-by: NMarc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2022-March/005073.html
Link: https://lore.kernel.org/r/164865115696.2943015.11097991776647323586.stgit@warthog.procyon.org.ukSigned-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

Fix the rxrpc_client tracepoint to not dereference conn to get the cid if
conn is NULL, as it does for other fields.

	RIP: 0010:trace_event_raw_event_rxrpc_client+0x7e/0xe0 [rxrpc]
	Call Trace:
	 rxrpc_activate_channels+0x62/0xb0 [rxrpc]
	 rxrpc_connect_call+0x481/0x650 [rxrpc]
	 ? wake_up_q+0xa0/0xa0
	 ? rxrpc_kernel_begin_call+0x12a/0x1b0 [rxrpc]
	 rxrpc_new_client_call+0x2a5/0x5e0 [rxrpc]

Fixes: 245500d8 ("rxrpc: Rewrite the client connection manager")
Reported-by: NMarc Dionne <marc.dionne@auristor.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NMarc Dionne <marc.dionne@auristor.com>

Rewrite the rxrpc client connection manager so that it can support multiple
connections for a given security key to a peer.  The following changes are
made:

 (1) For each open socket, the code currently maintains an rbtree with the
     connections placed into it, keyed by communications parameters.  This
     is tricky to maintain as connections can be culled from the tree or
     replaced within it.  Connections can require replacement for a number
     of reasons, e.g. their IDs span too great a range for the IDR data
     type to represent efficiently, the call ID numbers on that conn would
     overflow or the conn got aborted.

     This is changed so that there's now a connection bundle object placed
     in the tree, keyed on the same parameters.  The bundle, however, does
     not need to be replaced.

 (2) An rxrpc_bundle object can now manage the available channels for a set
     of parallel connections.  The lock that manages this is moved there
     from the rxrpc_connection struct (channel_lock).

 (3) There'a a dummy bundle for all incoming connections to share so that
     they have a channel_lock too.  It might be better to give each
     incoming connection its own bundle.  This bundle is not needed to
     manage which channels incoming calls are made on because that's the
     solely at whim of the client.

 (4) The restrictions on how many client connections are around are
     removed.  Instead, a previous patch limits the number of client calls
     that can be allocated.  Ordinarily, client connections are reaped
     after 2 minutes on the idle queue, but when more than a certain number
     of connections are in existence, the reaper starts reaping them after
     2s of idleness instead to get the numbers back down.

     It could also be made such that new call allocations are forced to
     wait until the number of outstanding connections subsides.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

The Rx protocol has a mechanism to help generate RTT samples that works by
a client transmitting a REQUESTED-type ACK when it receives a DATA packet
that has the REQUEST_ACK flag set.

The peer, however, may interpose other ACKs before transmitting the
REQUESTED-ACK, as can be seen in the following trace excerpt:

 rxrpc_tx_data: c=00000044 DATA d0b5ece8:00000001 00000001 q=00000001 fl=07
 rxrpc_rx_ack: c=00000044 00000001 PNG r=00000000 f=00000002 p=00000000 n=0
 rxrpc_rx_ack: c=00000044 00000002 REQ r=00000001 f=00000002 p=00000001 n=0
 ...

DATA packet 1 (q=xx) has REQUEST_ACK set (bit 1 of fl=xx).  The incoming
ping (labelled PNG) hard-acks the request DATA packet (f=xx exceeds the
sequence number of the DATA packet), causing it to be discarded from the Tx
ring.  The ACK that was requested (labelled REQ, r=xx references the serial
of the DATA packet) comes after the ping, but the sk_buff holding the
timestamp has gone and the RTT sample is lost.

This is particularly noticeable on RPC calls used to probe the service
offered by the peer.  A lot of peers end up with an unknown RTT because we
only ever sent a single RPC.  This confuses the server rotation algorithm.

Fix this by caching the information about the outgoing packet in RTT
calculations in the rxrpc_call struct rather than looking in the Tx ring.

A four-deep buffer is maintained and both REQUEST_ACK-flagged DATA and
PING-ACK transmissions are recorded in there.  When the appropriate
response ACK is received, the buffer is checked for a match and, if found,
an RTT sample is recorded.

If a received ACK refers to a packet with a later serial number than an
entry in the cache, that entry is presumed lost and the entry is made
available to record a new transmission.

ACKs types other than REQUESTED-type and PING-type cause any matching
sample to be cancelled as they don't necessarily represent a useful
measurement.

If there's no space in the buffer on ping/data transmission, the sample
base is discarded.

Fixes: 50235c4b ("rxrpc: Obtain RTT data by requesting ACKs on DATA packets")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

The trace symbol printer (__print_symbolic()) ignores symbols that map to
an empty string and prints the hex value instead.

Fix the symbol for rxrpc_cong_no_change to " -" instead of "" to avoid
this.

Fixes: b54a134a ("rxrpc: Fix handling of enums-to-string translation in tracing")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint to track received ACKs that are discarded due to being
outside of the Tx window.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

rxrpc currently uses a fixed 4s retransmission timeout until the RTT is
sufficiently sampled.  This can cause problems with some fileservers with
calls to the cache manager in the afs filesystem being dropped from the
fileserver because a packet goes missing and the retransmission timeout is
greater than the call expiry timeout.

Fix this by:

 (1) Copying the RTT/RTO calculation code from Linux's TCP implementation
     and altering it to fit rxrpc.

 (2) Altering the various users of the RTT to make use of the new SRTT
     value.

 (3) Replacing the use of rxrpc_resend_timeout to use the calculated RTO
     value instead (which is needed in jiffies), along with a backoff.

Notes:

 (1) rxrpc provides RTT samples by matching the serial numbers on outgoing
     DATA packets that have the RXRPC_REQUEST_ACK set and PING ACK packets
     against the reference serial number in incoming REQUESTED ACK and
     PING-RESPONSE ACK packets.

 (2) Each packet that is transmitted on an rxrpc connection gets a new
     per-connection serial number, even for retransmissions, so an ACK can
     be cross-referenced to a specific trigger packet.  This allows RTT
     information to be drawn from retransmitted DATA packets also.

 (3) rxrpc maintains the RTT/RTO state on the rxrpc_peer record rather than
     on an rxrpc_call because many RPC calls won't live long enough to
     generate more than one sample.

 (4) The calculated SRTT value is in units of 8ths of a microsecond rather
     than nanoseconds.

The (S)RTT and RTO values are displayed in /proc/net/rxrpc/peers.

Fixes: 17926a79 ([AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both"")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

rxrpc_put_call() calls trace_rxrpc_call() after it has done the decrement
of the refcount - which looks at the debug_id in the call record.  But
unless the refcount was reduced to zero, we no longer have the right to
look in the record and, indeed, it may be deleted by some other thread.

Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.

Fixes: e34d4234 ("rxrpc: Trace rxrpc_call usage")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

rxrpc_put_*conn() calls trace_rxrpc_conn() after they have done the
decrement of the refcount - which looks at the debug_id in the connection
record.  But unless the refcount was reduced to zero, we no longer have the
right to look in the record and, indeed, it may be deleted by some other
thread.

Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.

Fixes: 363deeab ("rxrpc: Add connection tracepoint and client conn state tracepoint")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

rxrpc_put_peer() calls trace_rxrpc_peer() after it has done the decrement
of the refcount - which looks at the debug_id in the peer record.  But
unless the refcount was reduced to zero, we no longer have the right to
look in the record and, indeed, it may be deleted by some other thread.

Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.

This can cause the following symptoms:

    BUG: KASAN: use-after-free in __rxrpc_put_peer net/rxrpc/peer_object.c:411
    [inline]
    BUG: KASAN: use-after-free in rxrpc_put_peer+0x685/0x6a0
    net/rxrpc/peer_object.c:435
    Read of size 8 at addr ffff888097ec0058 by task syz-executor823/24216

Fixes: 1159d4b4 ("rxrpc: Add a tracepoint to track rxrpc_peer refcounting")
Reported-by: syzbot+b9be979c55f2bea8ed30@syzkaller.appspotmail.com
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix the rxrpc_recvmsg tracepoint to handle being called with a NULL call
parameter.

Fixes: a25e21f0 ("rxrpc, afs: Use debug_ids rather than pointers in traces")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The in-place decryption routines in AF_RXRPC's rxkad security module
currently call skb_cow_data() to make sure the data isn't shared and that
the skb can be written over.  This has a problem, however, as the softirq
handler may be still holding a ref or the Rx ring may be holding multiple
refs when skb_cow_data() is called in rxkad_verify_packet() - and so
skb_shared() returns true and __pskb_pull_tail() dislikes that.  If this
occurs, something like the following report will be generated.

	kernel BUG at net/core/skbuff.c:1463!
	...
	RIP: 0010:pskb_expand_head+0x253/0x2b0
	...
	Call Trace:
	 __pskb_pull_tail+0x49/0x460
	 skb_cow_data+0x6f/0x300
	 rxkad_verify_packet+0x18b/0xb10 [rxrpc]
	 rxrpc_recvmsg_data.isra.11+0x4a8/0xa10 [rxrpc]
	 rxrpc_kernel_recv_data+0x126/0x240 [rxrpc]
	 afs_extract_data+0x51/0x2d0 [kafs]
	 afs_deliver_fs_fetch_data+0x188/0x400 [kafs]
	 afs_deliver_to_call+0xac/0x430 [kafs]
	 afs_wait_for_call_to_complete+0x22f/0x3d0 [kafs]
	 afs_make_call+0x282/0x3f0 [kafs]
	 afs_fs_fetch_data+0x164/0x300 [kafs]
	 afs_fetch_data+0x54/0x130 [kafs]
	 afs_readpages+0x20d/0x340 [kafs]
	 read_pages+0x66/0x180
	 __do_page_cache_readahead+0x188/0x1a0
	 ondemand_readahead+0x17d/0x2e0
	 generic_file_read_iter+0x740/0xc10
	 __vfs_read+0x145/0x1a0
	 vfs_read+0x8c/0x140
	 ksys_read+0x4a/0xb0
	 do_syscall_64+0x43/0xf0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by using skb_unshare() instead in the input path for DATA packets
that have a security index != 0.  Non-DATA packets don't need in-place
encryption and neither do unencrypted DATA packets.

Fixes: 248f219c ("rxrpc: Rewrite the data and ack handling code")
Reported-by: NJulian Wollrath <jwollrath@web.de>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Use the previously-added transmit-phase skbuff private flag to simplify the
socket buffer tracing a bit.  Which phase the skbuff comes from can now be
divined from the skb rather than having to be guessed from the call state.

We can also reduce the number of rxrpc_skb_trace values by eliminating the
difference between Tx and Rx in the symbols.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

rxrpc_queue_local() attempts to queue the local endpoint it is given and
then, if successful, prints a trace line.  The trace line includes the
current usage count - but we're not allowed to look at the local endpoint
at this point as we passed our ref on it to the workqueue.

Fix this by reading the usage count before queuing the work item.

Also fix the reading of local->debug_id for trace lines, which must be done
with the same consideration as reading the usage count.

Fixes: 09d2bf59 ("rxrpc: Add a tracepoint to track rxrpc_local refcounting")
Reported-by: syzbot+78e71c5bab4f76a6a719@syzkaller.appspotmail.com
Signed-off-by: NDavid Howells <dhowells@redhat.com>

If the rxrpc_eproto tracepoint is enabled, an oops will be cause by the
trace line that rxrpc_extract_header() tries to emit when a protocol error
occurs (typically because the packet is short) because the call argument is
NULL.

Fix this by using ?: to assume 0 as the debug_id if call is NULL.

This can then be induced by:

	echo -e '\0\0\0\0\0\0\0\0' | ncat -4u --send-only <addr> 20001

where addr has the following program running on it:

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>
	#include <sys/socket.h>
	#include <arpa/inet.h>
	#include <linux/rxrpc.h>
	int main(void)
	{
		struct sockaddr_rxrpc srx;
		int fd;
		memset(&srx, 0, sizeof(srx));
		srx.srx_family			= AF_RXRPC;
		srx.srx_service			= 0;
		srx.transport_type		= AF_INET;
		srx.transport_len		= sizeof(srx.transport.sin);
		srx.transport.sin.sin_family	= AF_INET;
		srx.transport.sin.sin_port	= htons(0x4e21);
		fd = socket(AF_RXRPC, SOCK_DGRAM, AF_INET6);
		bind(fd, (struct sockaddr *)&srx, sizeof(srx));
		sleep(20);
		return 0;
	}

It results in the following oops.

	BUG: kernel NULL pointer dereference, address: 0000000000000340
	#PF: supervisor read access in kernel mode
	#PF: error_code(0x0000) - not-present page
	...
	RIP: 0010:trace_event_raw_event_rxrpc_rx_eproto+0x47/0xac
	...
	Call Trace:
	 <IRQ>
	 rxrpc_extract_header+0x86/0x171
	 ? rcu_read_lock_sched_held+0x5d/0x63
	 ? rxrpc_new_skb+0xd4/0x109
	 rxrpc_input_packet+0xef/0x14fc
	 ? rxrpc_input_data+0x986/0x986
	 udp_queue_rcv_one_skb+0xbf/0x3d0
	 udp_unicast_rcv_skb.isra.8+0x64/0x71
	 ip_protocol_deliver_rcu+0xe4/0x1b4
	 ip_local_deliver+0xf0/0x154
	 __netif_receive_skb_one_core+0x50/0x6c
	 netif_receive_skb_internal+0x26b/0x2e9
	 napi_gro_receive+0xf8/0x1da
	 rtl8169_poll+0x303/0x4c4
	 net_rx_action+0x10e/0x333
	 __do_softirq+0x1a5/0x38f
	 irq_exit+0x54/0xc4
	 do_IRQ+0xda/0xf8
	 common_interrupt+0xf/0xf
	 </IRQ>
	 ...
	 ? cpuidle_enter_state+0x23c/0x34d
	 cpuidle_enter+0x2a/0x36
	 do_idle+0x163/0x1ea
	 cpu_startup_entry+0x1d/0x1f
	 start_secondary+0x157/0x172
	 secondary_startup_64+0xa4/0xb0

Fixes: a25e21f0 ("rxrpc, afs: Use debug_ids rather than pointers in traces")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NMarc Dionne <marc.dionne@auristor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public licence as published by
  the free software foundation either version 2 of the licence or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NAllison Randal <allison@lohutok.net>
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

rxrpc_disconnect_client_call() reads the call's connection ID protocol
value (call->cid) as part of that function's variable declarations.  This
is bad because it's not inside the locked section and so may race with
someone granting use of the channel to the call.

This manifests as an assertion failure (see below) where the call in the
presumed channel (0 because call->cid wasn't set when we read it) doesn't
match the call attached to the channel we were actually granted (if 1, 2 or
3).

Fix this by moving the read and dependent calculations inside of the
channel_lock section.  Also, only set the channel number and pointer
variables if cid is not zero (ie. unset).

This problem can be induced by injecting an occasional error in
rxrpc_wait_for_channel() before the call to schedule().

Make two further changes also:

 (1) Add a trace for wait failure in rxrpc_connect_call().

 (2) Drop channel_lock before BUG'ing in the case of the assertion failure.

The failure causes a trace akin to the following:

rxrpc: Assertion failed - 18446612685268945920(0xffff8880beab8c00) == 18446612685268621312(0xffff8880bea69800) is false
------------[ cut here ]------------
kernel BUG at net/rxrpc/conn_client.c:824!
...
RIP: 0010:rxrpc_disconnect_client_call+0x2bf/0x99d
...
Call Trace:
 rxrpc_connect_call+0x902/0x9b3
 ? wake_up_q+0x54/0x54
 rxrpc_new_client_call+0x3a0/0x751
 ? rxrpc_kernel_begin_call+0x141/0x1bc
 ? afs_alloc_call+0x1b5/0x1b5
 rxrpc_kernel_begin_call+0x141/0x1bc
 afs_make_call+0x20c/0x525
 ? afs_alloc_call+0x1b5/0x1b5
 ? __lock_is_held+0x40/0x71
 ? lockdep_init_map+0xaf/0x193
 ? lockdep_init_map+0xaf/0x193
 ? __lock_is_held+0x40/0x71
 ? yfs_fs_fetch_data+0x33b/0x34a
 yfs_fs_fetch_data+0x33b/0x34a
 afs_fetch_data+0xdc/0x3b7
 afs_read_dir+0x52d/0x97f
 afs_dir_iterate+0xa0/0x661
 ? iterate_dir+0x63/0x141
 iterate_dir+0xa2/0x141
 ksys_getdents64+0x9f/0x11b
 ? filldir+0x111/0x111
 ? do_syscall_64+0x3e/0x1a0
 __x64_sys_getdents64+0x16/0x19
 do_syscall_64+0x7d/0x1a0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: 45025bce ("rxrpc: Improve management and caching of client connection objects")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NMarc Dionne <marc.dionne@auristor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The life-checking function, which is used by kAFS to make sure that a call
is still live in the event of a pending signal, only samples the received
packet serial number counter; it doesn't actually provoke a change in the
counter, rather relying on the server to happen to give us a packet in the
time window.

Fix this by adding a function to force a ping to be transmitted.

kAFS then keeps track of whether there's been a stall, and if so, uses the
new function to ping the server, resetting the timeout to allow the reply
to come back.

If there's a stall, a ping and the call is *still* stalled in the same
place after another period, then the call will be aborted.

Fixes: bc5e3a54 ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Fixes: f4d15fb6 ("rxrpc: Provide functions for allowing cleaner handling of signals")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix the rxrpc_tx_packet trace line by storing the where parameter.

Fixes: 4764c0da ("rxrpc: Trace packet transmission")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix error distribution by immediately delivering the errors to all the
affected calls rather than deferring them to a worker thread.  The problem
with the latter is that retries and things can happen in the meantime when we
want to stop that sooner.

To this end:

 (1) Stop the error distributor from removing calls from the error_targets
     list so that peer->lock isn't needed to synchronise against other adds
     and removals.

 (2) Require the peer's error_targets list to be accessed with RCU, thereby
     avoiding the need to take peer->lock over distribution.

 (3) Don't attempt to affect a call's state if it is already marked complete.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Trace notifications from the softirq side of the socket to the
process-context side.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix the ACK proposal tracepoint outcomes list by making the one that's an
empty string not an empty string - which gets rendered as a hex number
string instead.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Trace successful packet transmission (kernel_sendmsg() succeeded, that is)
in AF_RXRPC.  We can share the enum that defines the transmission points
with the trace_rxrpc_tx_fail() tracepoint, so rename its constants to be
applicable to both.

Also, save the internal call->debug_id in the rxrpc_channel struct so that
it can be used in retransmission trace lines.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Sometimes an in-progress call will stop responding on the fileserver when
the fileserver quietly cancels the call with an internally marked abort
(RX_CALL_DEAD), without sending an ABORT to the client.

This causes the client's call to eventually expire from lack of incoming
packets directed its way, which currently leads to it being cancelled
locally with ETIME.  Note that it's not currently clear as to why this
happens as it's really hard to reproduce.

The rotation policy implement by kAFS, however, doesn't differentiate
between ETIME meaning we didn't get any response from the server and ETIME
meaning the call got cancelled mid-flow.  The latter leads to an oops when
fetching data as the rotation partially resets the afs_read descriptor,
which can result in a cleared page pointer being dereferenced because that
page has already been filled.

Handle this by the following means:

 (1) Set a flag on a call when we receive a packet for it.

 (2) Store the highest packet serial number so far received for a call
     (bearing in mind this may wrap).

 (3) If, when the "not received anything recently" timeout expires on a
     call, we've received at least one packet for a call and the connection
     as a whole has received packets more recently than that call, then
     cancel the call locally with ECONNRESET rather than ETIME.

     This indicates that the call was definitely in progress on the server.

 (4) In kAFS, if the rotation algorithm sees ECONNRESET rather than ETIME,
     don't try the next server, but rather abort the call.

     This avoids the oops as we don't try to reuse the afs_read struct.
     Rather, as-yet ungotten pages will be reread at a later data.

Also:

 (5) Add an rxrpc tracepoint to log detection of the call being reset.

Without this, I occasionally see an oops like the following:

    general protection fault: 0000 [#1] SMP PTI
    ...
    RIP: 0010:_copy_to_iter+0x204/0x310
    RSP: 0018:ffff8800cae0f828 EFLAGS: 00010206
    RAX: 0000000000000560 RBX: 0000000000000560 RCX: 0000000000000560
    RDX: ffff8800cae0f968 RSI: ffff8800d58b3312 RDI: 0005080000000000
    RBP: ffff8800cae0f968 R08: 0000000000000560 R09: ffff8800ca00f400
    R10: ffff8800c36f28d4 R11: 00000000000008c4 R12: ffff8800cae0f958
    R13: 0000000000000560 R14: ffff8800d58b3312 R15: 0000000000000560
    FS:  00007fdaef108080(0000) GS:ffff8800ca680000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007fb28a8fa000 CR3: 00000000d2a76002 CR4: 00000000001606e0
    Call Trace:
     skb_copy_datagram_iter+0x14e/0x289
     rxrpc_recvmsg_data.isra.0+0x6f3/0xf68
     ? trace_buffer_unlock_commit_regs+0x4f/0x89
     rxrpc_kernel_recv_data+0x149/0x421
     afs_extract_data+0x1e0/0x798
     ? afs_wait_for_call_to_complete+0xc9/0x52e
     afs_deliver_fs_fetch_data+0x33a/0x5ab
     afs_deliver_to_call+0x1ee/0x5e0
     ? afs_wait_for_call_to_complete+0xc9/0x52e
     afs_wait_for_call_to_complete+0x12b/0x52e
     ? wake_up_q+0x54/0x54
     afs_make_call+0x287/0x462
     ? afs_fs_fetch_data+0x3e6/0x3ed
     ? rcu_read_lock_sched_held+0x5d/0x63
     afs_fs_fetch_data+0x3e6/0x3ed
     afs_fetch_data+0xbb/0x14a
     afs_readpages+0x317/0x40d
     __do_page_cache_readahead+0x203/0x2ba
     ? ondemand_readahead+0x3a7/0x3c1
     ondemand_readahead+0x3a7/0x3c1
     generic_file_buffered_read+0x18b/0x62f
     __vfs_read+0xdb/0xfe
     vfs_read+0xb2/0x137
     ksys_read+0x50/0x8c
     do_syscall_64+0x7d/0x1a0
     entry_SYSCALL_64_after_hwframe+0x49/0xbe

Note the weird value in RDI which is a result of trying to kmap() a NULL
page pointer.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a tracepoint to log transmission failure from the UDP transport socket
being used by AF_RXRPC.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint to log received ICMP/ICMP6 events and other error
messages.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint to track reference counting on the rxrpc_peer struct.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint to track reference counting on the rxrpc_local struct.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint to track rxrpc calls moving into the completed state and
to log the completion type and the recorded error value and abort code.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

In rxrpc and afs, use the debug_ids that are monotonically allocated to
various objects as they're allocated rather than pointers as kernel
pointers are now hashed making them less useful.  Further, the debug ids
aren't reused anywhere nearly as quickly.

In addition, allow kernel services that use rxrpc, such as afs, to take
numbers from the rxrpc counter, assign them to their own call struct and
pass them in to rxrpc for both client and service calls so that the trace
lines for each will have the same ID tag.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint to trace packet resend events and to dump the Tx
annotation buffer for added illumination.
Signed-off-by: NDavid Howells <dhowells@rdhat.com>

RxRPC service endpoints expire like they're supposed to by the following
means:

 (1) Mark dead rxrpc_net structs (with ->live) rather than twiddling the
     global service conn timeout, otherwise the first rxrpc_net struct to
     die will cause connections on all others to expire immediately from
     then on.

 (2) Mark local service endpoints for which the socket has been closed
     (->service_closed) so that the expiration timeout can be much
     shortened for service and client connections going through that
     endpoint.

 (3) rxrpc_put_service_conn() needs to schedule the reaper when the usage
     count reaches 1, not 0, as idle conns have a 1 count.

 (4) The accumulator for the earliest time we might want to schedule for
     should be initialised to jiffies + MAX_JIFFY_OFFSET, not ULONG_MAX as
     the comparison functions use signed arithmetic.

 (5) Simplify the expiration handling, adding the expiration value to the
     idle timestamp each time rather than keeping track of the time in the
     past before which the idle timestamp must go to be expired.  This is
     much easier to read.

 (6) Ignore the timeouts if the net namespace is dead.

 (7) Restart the service reaper work item rather the client reaper.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

We need to transmit a packet every so often to act as a keepalive for the
peer (which has a timeout from the last time it received a packet) and also
to prevent any intervening firewalls from closing the route.

Do this by resetting a timer every time we transmit a packet.  If the timer
ever expires, we transmit a PING ACK packet and thereby also elicit a PING
RESPONSE ACK from the other side - which prevents our last-rx timeout from
expiring.

The timer is set to 1/6 of the last-rx timeout so that we can detect the
other side going away if it misses 6 replies in a row.

This is particularly necessary for servers where the processing of the
service function may take a significant amount of time.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add an extra timeout that is set/updated when we send a DATA packet that
has the request-ack flag set.  This allows us to detect if we don't get an
ACK in response to the latest flagged packet.

The ACK packet is adjudged to have been lost if it doesn't turn up within
2*RTT of the transmission.

If the timeout occurs, we schedule the sending of a PING ACK to find out
the state of the other side.  If a new DATA packet is ready to go sooner,
we cancel the sending of the ping and set the request-ack flag on that
instead.

If we get back a PING-RESPONSE ACK that indicates a lower tx_top than what
we had at the time of the ping transmission, we adjudge all the DATA
packets sent between the response tx_top and the ping-time tx_top to have
been lost and retransmit immediately.

Rather than sending a PING ACK, we could just pick a DATA packet and
speculatively retransmit that with request-ack set.  It should result in
either a REQUESTED ACK or a DUPLICATE ACK which we can then use in lieu the
a PING-RESPONSE ACK mentioned above.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix the rxrpc call expiration timeouts and make them settable from
userspace.  By analogy with other rx implementations, there should be three
timeouts:

 (1) "Normal timeout"

     This is set for all calls and is triggered if we haven't received any
     packets from the peer in a while.  It is measured from the last time
     we received any packet on that call.  This is not reset by any
     connection packets (such as CHALLENGE/RESPONSE packets).

     If a service operation takes a long time, the server should generate
     PING ACKs at a duration that's substantially less than the normal
     timeout so is to keep both sides alive.  This is set at 1/6 of normal
     timeout.

 (2) "Idle timeout"

     This is set only for a service call and is triggered if we stop
     receiving the DATA packets that comprise the request data.  It is
     measured from the last time we received a DATA packet.

 (3) "Hard timeout"

     This can be set for a call and specified the maximum lifetime of that
     call.  It should not be specified by default.  Some operations (such
     as volume transfer) take a long time.

Allow userspace to set/change the timeouts on a call with sendmsg, using a
control message:

	RXRPC_SET_CALL_TIMEOUTS

The data to the message is a number of 32-bit words, not all of which need
be given:

	u32 hard_timeout;	/* sec from first packet */
	u32 idle_timeout;	/* msec from packet Rx */
	u32 normal_timeout;	/* msec from data Rx */

This can be set in combination with any other sendmsg() that affects a
call.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Make it possible for a client to use AuriStor's service upgrade facility.

The client does this by adding an RXRPC_UPGRADE_SERVICE control message to
the first sendmsg() of a call.  This takes no parameters.

When recvmsg() starts returning data from the call, the service ID field in
the returned msg_name will reflect the result of the upgrade attempt.  If
the upgrade was ignored, srx_service will match what was set in the
sendmsg(); if the upgrade happened the srx_service will be altered to
indicate the service the server upgraded to.

Note that:

 (1) The choice of upgrade service is up to the server

 (2) Further client calls to the same server that would share a connection
     are blocked if an upgrade probe is in progress.

 (3) This should only be used to probe the service.  Clients should then
     use the returned service ID in all subsequent communications with that
     server (and not set the upgrade).  Note that the kernel will not
     retain this information should the connection expire from its cache.

 (4) If a server that supports upgrading is replaced by one that doesn't,
     whilst a connection is live, and if the replacement is running, say,
     OpenAFS 1.6.4 or older or an older IBM AFS, then the replacement
     server will not respond to packets sent to the upgraded connection.

     At this point, calls will time out and the server must be reprobed.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint (rxrpc_connect_call) to log the combination of rxrpc_call
pointer, afs_call pointer/user data and wire call parameters to make it
easier to match the tracebuffer contents to captured network packets.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint (rxrpc_rx_rwind_change) to log changes in a call's receive
window size as imposed by the peer through an ACK packet.
Signed-off-by: NDavid Howells <dhowells@redhat.com>