rxrpc_set_call_completion() returns bool, not int, so the ret variable
should match this.
rxrpc_call_completed() and __rxrpc_call_completed() should return the value
of rxrpc_set_call_completion().
Signed-off-by: David Howells <dhowells@redhat.com>
rxrpc calls shouldn't hold refs on the sock struct. This was done so that
the socket wouldn't go away whilst the call was in progress, such that the
call could reach the socket's queues.
However, we can mark the socket as requiring an RCU release and rely on the
RCU read lock.
To make this work, we do:
(1) rxrpc_release_call() removes the call's call user ID. This is now
only called from socket operations and not from the call processor:
rxrpc_accept_call() / rxrpc_kernel_accept_call()
rxrpc_reject_call() / rxrpc_kernel_reject_call()
rxrpc_kernel_end_call()
rxrpc_release_calls_on_socket()
rxrpc_recvmsg()
Though it is also called in the cleanup path of
rxrpc_accept_incoming_call() before we assign a user ID.
(2) Pass the socket pointer into rxrpc_release_call() rather than getting
it from the call so that we can get rid of uninitialised calls.
(3) Fix call processor queueing to pass a ref to the work queue and to
release that ref at the end of the processor function (or to pass it
back to the work queue if we have to requeue).
(4) Skip out of the call processor function asap if the call is complete
and don't requeue it if the call is complete.
(5) Clean up the call immediately that the refcount reaches 0 rather than
trying to defer it. Actual deallocation is deferred to RCU, however.
(6) Don't hold socket refs for allocated calls.
(7) Use the RCU read lock when queueing a message on a socket and treat
the call's socket pointer according to RCU rules and check it for
NULL.
We also need to use the RCU read lock when viewing a call through
procfs.
(8) Transmit the final ACK/ABORT to a client call in rxrpc_release_call()
if this hasn't been done yet so that we can then disconnect the call.
Once the call is disconnected, it won't have any access to the
connection struct and the UDP socket for the call work processor to be
able to send the ACK. Terminal retransmission will be handled by the
connection processor.
(9) Release all calls immediately on the closing of a socket rather than
trying to defer this. Incomplete calls will be aborted.
The call refcount model is much simplified. Refs are held on the call by:
(1) A socket's user ID tree.
(2) A socket's incoming call secureq and acceptq.
(3) A kernel service that has a call in progress.
(4) A queued call work processor. We have to take care to put any call
that we failed to queue.
(5) sk_buffs on a socket's receive queue. A future patch will get rid of
this.
Whilst we're at it, we can do:
(1) Get rid of the RXRPC_CALL_EV_RELEASE event. Release is now done
entirely from the socket routines and never from the call's processor.
(2) Get rid of the RXRPC_CALL_DEAD state. Calls now end in the
RXRPC_CALL_COMPLETE state.
(3) Get rid of the rxrpc_call::destroyer work item. Calls are now torn
down when their refcount reaches 0 and then handed over to RCU for
final cleanup.
(4) Get rid of the rxrpc_call::deadspan timer. Calls are cleaned up
immediately they're finished with and don't hang around.
Post-completion retransmission is handled by the connection processor
once the call is disconnected.
(5) Get rid of the dead call expiry setting as there's no longer a timer
to set.
(6) rxrpc_destroy_all_calls() can just check that the call list is empty.
Signed-off-by: David Howells <dhowells@redhat.com>
Use rxrpc_is_service_call() rather than rxrpc_conn_is_service() if the call
is available just in case call->conn is NULL.
Signed-off-by: David Howells <dhowells@redhat.com>
Pass the connection pointer to rxrpc_post_packet_to_call() as the call
might get disconnected whilst we're looking at it, but the connection
pointer determined by rxrpc_data_read() is guaranteed by RCU for the
duration of the call.
Signed-off-by: David Howells <dhowells@redhat.com>
Cache the security index in the rxrpc_call struct so that we can get at it
even when the call has been disconnected and the connection pointer
cleared.
Signed-off-by: David Howells <dhowells@redhat.com>
Use call->peer rather than call->conn->params.peer to avoid the possibility
of call->conn being NULL and, whilst we're at it, check it for NULL before we
access it.
Signed-off-by: David Howells <dhowells@redhat.com>
Improve the call tracking tracepoint by showing more differentiation
between some of the put and get events, including:
(1) Getting and putting refs for the socket call user ID tree.
(2) Getting and putting refs for queueing and failing to queue the call
processor work item.
Note that these aren't necessarily used in this patch, but will be taken
advantage of in future patches.
An enum is added for the event subtype numbers rather than coding them
directly as decimal numbers and a table of 3-letter strings is provided
rather than a sequence of ?: operators.
Signed-off-by: David Howells <dhowells@redhat.com>
Rearrange net/rxrpc/sendmsg.c to be in a more logical order. This makes it
easier to follow and eliminates forward declarations.
Signed-off-by: David Howells <dhowells@redhat.com>
It seems the local epoch should only be changed on boot, so remove the code
that changes it for client connections.
Signed-off-by: David Howells <dhowells@redhat.com>
Create a random epoch value rather than a time-based one on startup and set
the top bit to indicate that this is the case.
Also create a random starting client connection ID value. This will be
incremented from here as new client connections are created.
Signed-off-by: David Howells <dhowells@redhat.com>
We must set the client call state to RXRPC_CALL_CLIENT_SEND_REQUEST before
attaching the call to the connection struct, not after, as it's liable to
receive errors and conn aborts as soon as the assignment is made - and
these will cause its state to be changed outside of the initiating thread's
control.
Signed-off-by: David Howells <dhowells@redhat.com>
Fix the following uninitialised variable warning:
../net/rxrpc/call_event.c: In function 'rxrpc_process_call':
../net/rxrpc/call_event.c:879:58: warning: 'error' may be used uninitialized in this function [-Wmaybe-uninitialized]
_debug("post net error %d", error);
^
Signed-off-by: David Howells <dhowells@redhat.com>
gcc -Wmaybe-initialized correctly points out a newly introduced bug
through which we can end up calling rxrpc_queue_call() for a dead
connection:
net/rxrpc/call_object.c: In function 'rxrpc_mark_call_released':
net/rxrpc/call_object.c:600:5: error: 'sched' may be used uninitialized in this function [-Werror=maybe-uninitialized]
This sets the 'sched' variable to zero to restore the previous
behavior.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: f5c17aaeb2 ("rxrpc: Calls should only have one terminal state")
Signed-off-by: David Howells <dhowells@redhat.com>
Don't expose skbs to in-kernel users, such as the AFS filesystem, but
instead provide a notification hook the indicates that a call needs
attention and another that indicates that there's a new call to be
collected.
This makes the following possibilities more achievable:
(1) Call refcounting can be made simpler if skbs don't hold refs to calls.
(2) skbs referring to non-data events will be able to be freed much sooner
rather than being queued for AFS to pick up as rxrpc_kernel_recv_data
will be able to consult the call state.
(3) We can shortcut the receive phase when a call is remotely aborted
because we don't have to go through all the packets to get to the one
cancelling the operation.
(4) It makes it easier to do encryption/decryption directly between AFS's
buffers and sk_buffs.
(5) Encryption/decryption can more easily be done in the AFS's thread
contexts - usually that of the userspace process that issued a syscall
- rather than in one of rxrpc's background threads on a workqueue.
(6) AFS will be able to wait synchronously on a call inside AF_RXRPC.
To make this work, the following interface function has been added:
int rxrpc_kernel_recv_data(
struct socket *sock, struct rxrpc_call *call,
void *buffer, size_t bufsize, size_t *_offset,
bool want_more, u32 *_abort_code);
This is the recvmsg equivalent. It allows the caller to find out about the
state of a specific call and to transfer received data into a buffer
piecemeal.
afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction
logic between them. They don't wait synchronously yet because the socket
lock needs to be dealt with.
Five interface functions have been removed:
rxrpc_kernel_is_data_last()
rxrpc_kernel_get_abort_code()
rxrpc_kernel_get_error_number()
rxrpc_kernel_free_skb()
rxrpc_kernel_data_consumed()
As a temporary hack, sk_buffs going to an in-kernel call are queued on the
rxrpc_call struct (->knlrecv_queue) rather than being handed over to the
in-kernel user. To process the queue internally, a temporary function,
temp_deliver_data() has been added. This will be replaced with common code
between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a
future patch.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass struct socket * to more rxrpc kernel interface functions. They should
be starting from this rather than the socket pointer in the rxrpc_call
struct if they need to access the socket.
I have left:
rxrpc_kernel_is_data_last()
rxrpc_kernel_get_abort_code()
rxrpc_kernel_get_error_number()
rxrpc_kernel_free_skb()
rxrpc_kernel_data_consumed()
unmodified as they're all about to be removed (and, in any case, don't
touch the socket).
Signed-off-by: David Howells <dhowells@redhat.com>
Provide a function so that kernel users, such as AFS, can ask for the peer
address of a call:
void rxrpc_kernel_get_peer(struct rxrpc_call *call,
struct sockaddr_rxrpc *_srx);
In the future the kernel service won't get sk_buffs to look inside.
Further, this allows us to hide any canonicalisation inside AF_RXRPC for
when IPv6 support is added.
Also propagate this through to afs_find_server() and issue a warning if we
can't handle the address family yet.
Signed-off-by: David Howells <dhowells@redhat.com>
Condense the terminal states of a call state machine to a single state,
plus a separate completion type value. The value is then set, along with
error and abort code values, only when the call is transitioned to the
completion state.
Helpers are provided to simplify this.
Signed-off-by: David Howells <dhowells@redhat.com>
The call pointer in a channel on a connection will be NULL if there's no
active call on that channel. rxrpc_abort_calls() needs to check for this
before trying to take the call's state_lock.
Signed-off-by: David Howells <dhowells@redhat.com>
Improve the management and caching of client rxrpc connection objects.
From this point, client connections will be managed separately from service
connections because AF_RXRPC controls the creation and re-use of client
connections but doesn't have that luxury with service connections.
Further, there will be limits on the numbers of client connections that may
be live on a machine. No direct restriction will be placed on the number
of client calls, excepting that each client connection can support a
maximum of four concurrent calls.
Note that, for a number of reasons, we don't want to simply discard a
client connection as soon as the last call is apparently finished:
(1) Security is negotiated per-connection and the context is then shared
between all calls on that connection. The context can be negotiated
again if the connection lapses, but that involves holding up calls
whilst at least two packets are exchanged and various crypto bits are
performed - so we'd ideally like to cache it for a little while at
least.
(2) If a packet goes astray, we will need to retransmit a final ACK or
ABORT packet. To make this work, we need to keep around the
connection details for a little while.
(3) The locally held structures represent some amount of setup time, to be
weighed against their occupation of memory when idle.
To this end, the client connection cache is managed by a state machine on
each connection. There are five states:
(1) INACTIVE - The connection is not held in any list and may not have
been exposed to the world. If it has been previously exposed, it was
discarded from the idle list after expiring.
(2) WAITING - The connection is waiting for the number of client conns to
drop below the maximum capacity. Calls may be in progress upon it
from when it was active and got culled.
The connection is on the rxrpc_waiting_client_conns list which is kept
in to-be-granted order. Culled conns with waiters go to the back of
the queue just like new conns.
(3) ACTIVE - The connection has at least one call in progress upon it, it
may freely grant available channels to new calls and calls may be
waiting on it for channels to become available.
The connection is on the rxrpc_active_client_conns list which is kept
in activation order for culling purposes.
(4) CULLED - The connection got summarily culled to try and free up
capacity. Calls currently in progress on the connection are allowed
to continue, but new calls will have to wait. There can be no waiters
in this state - the conn would have to go to the WAITING state
instead.
(5) IDLE - The connection has no calls in progress upon it and must have
been exposed to the world (ie. the EXPOSED flag must be set). When it
expires, the EXPOSED flag is cleared and the connection transitions to
the INACTIVE state.
The connection is on the rxrpc_idle_client_conns list which is kept in
order of how soon they'll expire.
A connection in the ACTIVE or CULLED state must have at least one active
call upon it; if in the WAITING state it may have active calls upon it;
other states may not have active calls.
As long as a connection remains active and doesn't get culled, it may
continue to process calls - even if there are connections on the wait
queue. This simplifies things a bit and reduces the amount of checking we
need do.
There are a couple flags of relevance to the cache:
(1) EXPOSED - The connection ID got exposed to the world. If this flag is
set, an extra ref is added to the connection preventing it from being
reaped when it has no calls outstanding. This flag is cleared and the
ref dropped when a conn is discarded from the idle list.
(2) DONT_REUSE - The connection should be discarded as soon as possible and
should not be reused.
This commit also provides a number of new settings:
(*) /proc/net/rxrpc/max_client_conns
The maximum number of live client connections. Above this number, new
connections get added to the wait list and must wait for an active
conn to be culled. Culled connections can be reused, but they will go
to the back of the wait list and have to wait.
(*) /proc/net/rxrpc/reap_client_conns
If the number of desired connections exceeds the maximum above, the
active connection list will be culled until there are only this many
left in it.
(*) /proc/net/rxrpc/idle_conn_expiry
The normal expiry time for a client connection, provided there are
fewer than reap_client_conns of them around.
(*) /proc/net/rxrpc/idle_conn_fast_expiry
The expedited expiry time, used when there are more than
reap_client_conns of them around.
Note that I combined the Tx wait queue with the channel grant wait queue to
save space as only one of these should be in use at once.
Note also that, for the moment, the service connection cache still uses the
old connection management code.
Signed-off-by: David Howells <dhowells@redhat.com>
The main connection list is used for two independent purposes: primarily it
is used to find connections to reap and secondarily it is used to list
connections in procfs.
Split the procfs list out from the reap list. This allows us to stop using
the reap list for client connections when they acquire a separate
management strategy from service collections.
The client connections will not be on a management single list, and sometimes
won't be on a management list at all. This doesn't leave them floating,
however, as they will also be on an rb-tree rooted on the socket so that the
socket can find them to dispatch calls.
Signed-off-by: David Howells <dhowells@redhat.com>
Make /proc/net/rxrpc_calls safer by stashing a copy of the peer pointer in
the rxrpc_call struct and checking in the show routine that the peer
pointer, the socket pointer and the local pointer obtained from the socket
pointer aren't NULL before we use them.
Signed-off-by: David Howells <dhowells@redhat.com>
If a duplicate packet comes in for a call that has just completed on a
connection's channel then there will be an oops in the data_ready handler
because it tries to examine the connection struct via a call struct (which
we don't have - the pointer is unset).
Since the connection struct pointer is available to us, go direct instead.
Also, the ACK packet to be retransmitted needs three octets of padding
between the soft ack list and the ackinfo.
Fixes: 18bfeba50d ("rxrpc: Perform terminal call ACK/ABORT retransmission from conn processor")
Signed-off-by: David Howells <dhowells@redhat.com>
Perform terminal call ACK/ABORT retransmission in the connection processor
rather than in the call processor. With this change, once last_call is
set, no more incoming packets will be routed to the corresponding call or
any earlier calls on that channel (call IDs must only increase on a channel
on a connection).
Further, if a packet's callNumber is before the last_call ID or a packet is
aimed at successfully completed service call then that packet is discarded
and ignored.
Signed-off-by: David Howells <dhowells@redhat.com>
Calculate the serial number skew in the data_ready handler when a packet
has been received and a connection looked up. The skew is cached in the
sk_buff's priority field.
The connection highest received serial number is updated at this time also.
This can be done without locks or atomic instructions because, at this
point, the code is serialised by the socket.
This generates more accurate skew data because if the packet is offloaded
to a work queue before this is determined, more packets may come in,
bumping the highest serial number and thereby increasing the apparent skew.
This also removes some unnecessary atomic ops.
Signed-off-by: David Howells <dhowells@redhat.com>
Set the connection expiry time when a connection becomes idle rather than
doing this in rxrpc_put_connection(). This makes the put path more
efficient (it is likely to be called occasionally whilst a connection has
outstanding calls because active workqueue items needs to be given a ref).
The time is also preset in the connection allocator in case the connection
never gets used.
Signed-off-by: David Howells <dhowells@redhat.com>
Drop the channel number (channel) field from the rxrpc_call struct to
reduce the size of the call struct. The field is redundant: if the call is
attached to a connection, the channel can be obtained from there by AND'ing
with RXRPC_CHANNELMASK.
Signed-off-by: David Howells <dhowells@redhat.com>
When clearing a socket, we should clear the securing-in-progress list
first, then the accept queue and last the main call tree because that's the
order in which a call progresses. Not that a call should move from the
accept queue to the main tree whilst we're shutting down a socket, but it a
call could possibly move from sequreq to acceptq whilst we're clearing up.
Signed-off-by: David Howells <dhowells@redhat.com>
Do a little tidying of the rxrpc_call struct:
(1) in_clientflag is no longer compared against the value that's in the
packet, so keeping it in this form isn't necessary. Use a flag in
flags instead and provide a pair of wrapper functions.
(2) We don't read the epoch value, so that can go.
(3) Move what remains of the data that were used for hashing up in the
struct to be with the channel number.
(4) Get rid of the local pointer. We can get at this via the socket
struct and we only use this in the procfs viewer.
Signed-off-by: David Howells <dhowells@redhat.com>
Once a packet has been posted to a connection in the data_ready handler, we
mustn't try reposting if we then find that the connection is dying as the
refcount has been given over to the dying connection and the packet might
no longer exist.
Losing the packet isn't a problem as the peer will retransmit.
Signed-off-by: David Howells <dhowells@redhat.com>
The call state machine processor sets up the message parameters for a UDP
message that it might need to transmit in advance on the basis that there's
a very good chance it's going to have to transmit either an ACK or an
ABORT. This requires it to look in the connection struct to retrieve some
of the parameters.
However, if the call is complete, the call connection pointer may be NULL
to dissuade the processor from transmitting a message. However, there are
some situations where the processor is still going to be called - and it's
still going to set up message parameters whether it needs them or not.
This results in a NULL pointer dereference at:
net/rxrpc/call_event.c:837
To fix this, skip the message pre-initialisation if there's no connection
attached.
Signed-off-by: David Howells <dhowells@redhat.com>
If rxrpc_new_client_call() fails to make a connection, the call record that
it allocated needs to be marked as RXRPC_CALL_RELEASED before it is passed
to rxrpc_put_call() to indicate that it no longer has any attachment to the
AF_RXRPC socket.
Without this, an assertion failure may occur at:
net/rxrpc/call_object:635
Signed-off-by: David Howells <dhowells@redhat.com>
A newly added bugfix caused an uninitialized variable to be
used for printing debug output. This is harmless as long
as the debug setting is disabled, but otherwise leads to an
immediate crash.
gcc warns about this when -Wmaybe-uninitialized is enabled:
net/rxrpc/call_object.c: In function 'rxrpc_release_call':
net/rxrpc/call_object.c:496:163: error: 'sp' may be used uninitialized in this function [-Werror=maybe-uninitialized]
The initialization was removed but one of the users remains.
This adds back the initialization.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 372ee16386 ("rxrpc: Fix races between skb free, ACK generation and replying")
Signed-off-by: David Howells <dhowells@redhat.com>
Inside the kafs filesystem it is possible to occasionally have a call
processed and terminated before we've had a chance to check whether we need
to clean up the rx queue for that call because afs_send_simple_reply() ends
the call when it is done, but this is done in a workqueue item that might
happen to run to completion before afs_deliver_to_call() completes.
Further, it is possible for rxrpc_kernel_send_data() to be called to send a
reply before the last request-phase data skb is released. The rxrpc skb
destructor is where the ACK processing is done and the call state is
advanced upon release of the last skb. ACK generation is also deferred to
a work item because it's possible that the skb destructor is not called in
a context where kernel_sendmsg() can be invoked.
To this end, the following changes are made:
(1) kernel_rxrpc_data_consumed() is added. This should be called whenever
an skb is emptied so as to crank the ACK and call states. This does
not release the skb, however. kernel_rxrpc_free_skb() must now be
called to achieve that. These together replace
rxrpc_kernel_data_delivered().
(2) kernel_rxrpc_data_consumed() is wrapped by afs_data_consumed().
This makes afs_deliver_to_call() easier to work as the skb can simply
be discarded unconditionally here without trying to work out what the
return value of the ->deliver() function means.
The ->deliver() functions can, via afs_data_complete(),
afs_transfer_reply() and afs_extract_data() mark that an skb has been
consumed (thereby cranking the state) without the need to
conditionally free the skb to make sure the state is correct on an
incoming call for when the call processor tries to send the reply.
(3) rxrpc_recvmsg() now has to call kernel_rxrpc_data_consumed() when it
has finished with a packet and MSG_PEEK isn't set.
(4) rxrpc_packet_destructor() no longer calls rxrpc_hard_ACK_data().
Because of this, we no longer need to clear the destructor and put the
call before we free the skb in cases where we don't want the ACK/call
state to be cranked.
(5) The ->deliver() call-type callbacks are made to return -EAGAIN rather
than 0 if they expect more data (afs_extract_data() returns -EAGAIN to
the delivery function already), and the caller is now responsible for
producing an abort if that was the last packet.
(6) There are many bits of unmarshalling code where:
ret = afs_extract_data(call, skb, last, ...);
switch (ret) {
case 0: break;
case -EAGAIN: return 0;
default: return ret;
}
is to be found. As -EAGAIN can now be passed back to the caller, we
now just return if ret < 0:
ret = afs_extract_data(call, skb, last, ...);
if (ret < 0)
return ret;
(7) Checks for trailing data and empty final data packets has been
consolidated as afs_data_complete(). So:
if (skb->len > 0)
return -EBADMSG;
if (!last)
return 0;
becomes:
ret = afs_data_complete(call, skb, last);
if (ret < 0)
return ret;
(8) afs_transfer_reply() now checks the amount of data it has against the
amount of data desired and the amount of data in the skb and returns
an error to induce an abort if we don't get exactly what we want.
Without these changes, the following oops can occasionally be observed,
particularly if some printks are inserted into the delivery path:
general protection fault: 0000 [#1] SMP
Modules linked in: kafs(E) af_rxrpc(E) [last unloaded: af_rxrpc]
CPU: 0 PID: 1305 Comm: kworker/u8:3 Tainted: G E 4.7.0-fsdevel+ #1303
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Workqueue: kafsd afs_async_workfn [kafs]
task: ffff88040be041c0 ti: ffff88040c070000 task.ti: ffff88040c070000
RIP: 0010:[<ffffffff8108fd3c>] [<ffffffff8108fd3c>] __lock_acquire+0xcf/0x15a1
RSP: 0018:ffff88040c073bc0 EFLAGS: 00010002
RAX: 6b6b6b6b6b6b6b6b RBX: 0000000000000000 RCX: ffff88040d29a710
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88040d29a710
RBP: ffff88040c073c70 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88040be041c0 R15: ffffffff814c928f
FS: 0000000000000000(0000) GS:ffff88041fa00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa4595f4750 CR3: 0000000001c14000 CR4: 00000000001406f0
Stack:
0000000000000006 000000000be04930 0000000000000000 ffff880400000000
ffff880400000000 ffffffff8108f847 ffff88040be041c0 ffffffff81050446
ffff8803fc08a920 ffff8803fc08a958 ffff88040be041c0 ffff88040c073c38
Call Trace:
[<ffffffff8108f847>] ? mark_held_locks+0x5e/0x74
[<ffffffff81050446>] ? __local_bh_enable_ip+0x9b/0xa1
[<ffffffff8108f9ca>] ? trace_hardirqs_on_caller+0x16d/0x189
[<ffffffff810915f4>] lock_acquire+0x122/0x1b6
[<ffffffff810915f4>] ? lock_acquire+0x122/0x1b6
[<ffffffff814c928f>] ? skb_dequeue+0x18/0x61
[<ffffffff81609dbf>] _raw_spin_lock_irqsave+0x35/0x49
[<ffffffff814c928f>] ? skb_dequeue+0x18/0x61
[<ffffffff814c928f>] skb_dequeue+0x18/0x61
[<ffffffffa009aa92>] afs_deliver_to_call+0x344/0x39d [kafs]
[<ffffffffa009ab37>] afs_process_async_call+0x4c/0xd5 [kafs]
[<ffffffffa0099e9c>] afs_async_workfn+0xe/0x10 [kafs]
[<ffffffff81063a3a>] process_one_work+0x29d/0x57c
[<ffffffff81064ac2>] worker_thread+0x24a/0x385
[<ffffffff81064878>] ? rescuer_thread+0x2d0/0x2d0
[<ffffffff810696f5>] kthread+0xf3/0xfb
[<ffffffff8160a6ff>] ret_from_fork+0x1f/0x40
[<ffffffff81069602>] ? kthread_create_on_node+0x1cf/0x1cf
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The rxrpc_lookup_peer() function returns NULL on error, it never returns
error pointers.
Fixes: 8496af50eb ('rxrpc: Use RCU to access a peer's service connection tree')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
security initialized after alloc workqueue, so we should exit security
before destroy workqueue in the error handing.
Fixes: 648af7fca1 ("rxrpc: Absorb the rxkad security module")
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
The call hash table is now no longer used as calls are looked up directly
by channel slot on the connection, so kill it off.
Signed-off-by: David Howells <dhowells@redhat.com>
Move to using RCU access to a peer's service connection tree when routing
an incoming packet. This is done using a seqlock to trigger retrying of
the tree walk if a change happened.
Further, we no longer get a ref on the connection looked up in the
data_ready handler unless we queue the connection's work item - and then
only if the refcount > 0.
Note that I'm avoiding the use of a hash table for service connections
because each service connection is addressed by a 62-bit number
(constructed from epoch and connection ID >> 2) that would allow the client
to engage in bucket stuffing, given knowledge of the hash algorithm.
Peers, however, are hashed as the network address is less controllable by
the client. The total number of peers will also be limited in a future
commit.
Signed-off-by: David Howells <dhowells@redhat.com>
Overhaul the usage count accounting for the rxrpc_connection struct to make
it easier to implement RCU access from the data_ready handler.
The problem is that currently we're using a lock to prevent the garbage
collector from trying to clean up a connection that we're contemplating
unidling. We could just stick incoming packets on the connection we find,
but we've then got a problem that we may race when dispatching a work item
to process it as we need to give that a ref to prevent the rxrpc_connection
struct from disappearing in the meantime.
Further, incoming packets may get discarded if attached to an
rxrpc_connection struct that is going away. Whilst this is not a total
disaster - the client will presumably resend - it would delay processing of
the call. This would affect the AFS client filesystem's service manager
operation.
To this end:
(1) We now maintain an extra count on the connection usage count whilst it
is on the connection list. This mean it is not in use when its
refcount is 1.
(2) When trying to reuse an old connection, we only increment the refcount
if it is greater than 0. If it is 0, we replace it in the tree with a
new candidate connection.
(3) Two connection flags are added to indicate whether or not a connection
is in the local's client connection tree (used by sendmsg) or the
peer's service connection tree (used by data_ready). This makes sure
that we don't try and remove a connection if it got replaced.
The flags are tested under lock with the removal operation to prevent
the reaper from killing the rxrpc_connection struct whilst someone
else is trying to effect a replacement.
This could probably be alleviated by using memory barriers between the
flag set/test and the rb_tree ops. The rb_tree op would still need to
be under the lock, however.
(4) When trying to reap an old connection, we try to flip the usage count
from 1 to 0. If it's not 1 at that point, then it must've come back
to life temporarily and we ignore it.
Signed-off-by: David Howells <dhowells@redhat.com>
David Howells