Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We're seeing hangs in the NFS client code, with loops of the form:

 RPC: 30317 xmit incomplete (267368 left of 524448)
 RPC: 30317 call_status (status -11)
 RPC: 30317 call_transmit (status 0)
 RPC: 30317 xprt_prepare_transmit
 RPC: 30317 xprt_transmit(524448)
 RPC:       xs_tcp_send_request(267368) = -11
 RPC: 30317 xmit incomplete (267368 left of 524448)
 RPC: 30317 call_status (status -11)
 RPC: 30317 call_transmit (status 0)
 RPC: 30317 xprt_prepare_transmit
 RPC: 30317 xprt_transmit(524448)

Turns out commit ceb5d58b ("net: fix sock_wake_async() rcu protection")
moved SOCKWQ_ASYNC_NOSPACE out of sock->flags and into sk->sk_wq->flags,
however it never tried to fix up the code in net/sunrpc.

The new idiom is to use the flags in the RCU protected struct socket_wq.
While we're at it, clear out the now redundant places where we set/clear
SOCKWQ_ASYNC_NOSPACE and SOCK_NOSPACE. In principle, sk_stream_wait_memory()
is supposed to set these for us, so we only need to clear them in the
particular case of our ->write_space() callback.

Fixes: ceb5d58b ("net: fix sock_wake_async() rcu protection")
Cc: Eric Dumazet <edumazet@google.com>
Cc: stable@vger.kernel.org # 4.4
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

xs_reclassify_socket4() and friends used to be called directly.
xs_reclassify_socket() is called instead nowadays.

The xs_reclassify_socketX() helper functions are empty when
CONFIG_DEBUG_LOCK_ALLOC is not defined.  Drop them since they have no
callers.

Note that AF_LOCAL still calls xs_reclassify_socketu() directly but is
easily converted to generic xs_reclassify_socket().
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This patch is a cleanup to make following patch easier to
review.

Goal is to move SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA
from (struct socket)->flags to a (struct socket_wq)->flags
to benefit from RCU protection in sock_wake_async()

To ease backports, we rename both constants.

Two new helpers, sk_set_bit(int nr, struct sock *sk)
and sk_clear_bit(int net, struct sock *sk) are added so that
following patch can change their implementation.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Due to incorrect len type bc_send_request returned always zero.

The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/assign_signed_to_unsigned.cocci [1].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2046107Signed-off-by: NAndrzej Hajda <a.hajda@samsung.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Forechannel transports get their own "bc_up" method to create an
endpoint for the backchannel service.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
[Anna Schumaker: Add forward declaration of struct net to xprt.h]
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

xprt_{setup,destroy}_backchannel() won't be adequate for RPC/RMDA
bi-direction. In particular, receive buffers have to be pre-
registered and posted in order to receive incoming backchannel
requests.

Add a virtual function call to allow the insertion of appropriate
backchannel setup and destruction methods for each transport.

In addition, freeing a backchannel request is a little different
for RPC/RDMA. Introduce an rpc_xprt_op to handle the difference.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Tested-By: NDevesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

If we're sending more pages via kernel_sendpage(), then set
MSG_SENDPAGE_NOTLAST.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

If we're sending more than one page via kernel_sendpage(), then set
MSG_SENDPAGE_NOTLAST between the pages so that we don't send suboptimal
frames (see commit 2f533844 and commit 35f9c09f).
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Now that we've done it for TCP and UDP, let's convert AF_LOCAL as well.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Now that we've done it for TCP, let's convert UDP as well.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Stream protocols such as TCP can often build up a backlog of data to be
read due to ordering. Combine this with the fact that some workloads such
as NFS read()-intensive workloads need to receive a lot of data per RPC
call, and it turns out that receiving the data from inside a softirq
context can cause starvation.

The following patch moves the TCP data receive into a workqueue context.
We still end up calling tcp_read_sock(), but we do so from a process
context, meaning that softirqs are enabled for most of the time.

With this patch, I see a doubling of read bandwidth when running a
multi-threaded iozone workload between a virtual client and server setup.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Move the TCP data receive loop out of xs_tcp_data_ready(). Doing so
will allow us to move the data receive out of the softirq context in
a set of followup patches.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Under all conditions, it should be quite sufficient just to mark
the socket as disconnected. It will then be closed by the
transport shutdown or reconnect code.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Commit 718ba5b8, moved the responsibility for unlocking the socket to
xs_tcp_setup_socket, meaning that the socket will be unlocked before we
know that it has finished trying to connect. The following patch is based on
an initial patch by Russell King to ensure that we delay clearing the
XPRT_CONNECTING flag until we either know that we failed to initiate
a connection attempt, or the connection attempt itself failed.

Fixes: 718ba5b8 ("SUNRPC: Add helpers to prevent socket create from racing")
Reported-by: NRussell King <linux@arm.linux.org.uk>
Reported-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Tested-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Tested-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When we're destroying the socket transport, we need to ensure that
we cancel any existing delayed connection attempts, and order them
w.r.t. the call to xs_close().
Reported-by: N"Suzuki K. Poulose" <suzuki.poulose@arm.com>
Acked-by: NJeff Layton <jlayton@poochiereds.net>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Add a shutdown() call before we release the socket in order to ensure the
reset is sent before we try to reconnect.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

In case the reconnection attempt fails.

Cc: stable@vger.kernel.org
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Follow up to commit c4a7ca77 ("SUNRPC: Allow waiting on memory
allocation"). Allows the RPC socket code to do non-IO blocking.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It is rather pointless to test the value of transport->inet after
calling xs_reset_transport(), since it will always be zero, and
so we will never see any exponential back off behaviour.
Also don't force early connections for SOFTCONN tasks. If the server
disconnects us, we should respect the exponential backoff.

Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The networking layer does not reliably report the distinction between
a non-block write failing because:
 1/ the queue is too full already and
 2/ a memory allocation attempt failed.

The distinction is important because in the first case it is
appropriate to retry as soon as the socket reports that it is
writable, and in the second case a small delay is required as the
socket will most likely report as writable but kmalloc could still
fail.

sk_stream_wait_memory() exhibits this distinction nicely, setting
'vm_wait' if a small wait is needed.  However in the non-blocking case
it always returns -EAGAIN no matter the cause of the failure.  This
-EAGAIN call get all the way to sunrpc.

The sunrpc layer expects EAGAIN to indicate the first cause, and
ENOBUFS to indicate the second.  Various documentation suggests that
this is not unreasonable, but does not guarantee the desired error
codes.

The result of getting -EAGAIN when -ENOBUFS is expected is that the
send is tried again in a tight loop and soft lockups are reported.

so: add tests after calls to xs_sendpages() to translate -EAGAIN into
-ENOBUFS if the socket is writable.  This cannot happen inside
xs_sendpages() as the test for "is socket writable" is different
between TCP and UDP.

With this change, the tight loop retrying xs_sendpages() becomes a
loop which only retries every 250ms, and so will not trigger a
soft-lockup warning.

It is possible that the write did fail because the queue was too full
and by the time xs_sendpages() completed, the queue was writable
again.  In this case an extra 250ms delay is inserted that isn't
really needed.  This circumstance suggests a degree of congestion so a
delay is not necessarily a bad thing, and it can only cause a single
250ms delay, not a series of them.
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

ENOBUFS means that memory allocations are failing due to an actual
low memory situation. It should not be confused with being out of
socket buffer space.

Handle the problem by just punting to the delay in call_status.
Reported-by: NNeil Brown <neilb@suse.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Use the TCP_USER_TIMEOUT socket option to advertise to the server
how long we will keep the connection open if there is unacknowledged
data. See RFC5482.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

This fixes a regression introduced by commit caf4ccd4 ("SUNRPC:
Make xs_tcp_close() do a socket shutdown rather than a sock_release").
Prior to that commit, the autoclose feature would ensure that an
idle connection would result in the socket being both disconnected and
released, whereas now only gets disconnected.

While the current behaviour is harmless, it does leave the port bound
until either RPC traffic resumes or the RPC client is shut down.
Reported-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It has been exceptionally useful to exercise the logic that handles
local immediate errors and RDMA connection loss.  To enable
developers to test this regularly and repeatably, add logic to
simulate connection loss every so often.

Fault injection is disabled by default. It is enabled with

  $ sudo echo xxx > /sys/kernel/debug/sunrpc/inject_fault/disconnect

where "xxx" is a large positive number of transport method calls
before a disconnect. A value of several thousand is usually a good
number that allows reasonable forward progress while still causing a
lot of connection drops.

These hooks are disabled when SUNRPC_DEBUG is turned off.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

RDMA xprts don't have a sock_xprt, but an rdma_xprt, so the
xs_swapper_enable/disable functions will likely oops when fed an RDMA
xprt. Turn these functions into rpc_xprt_ops so that that doesn't
occur. For now the RDMA versions are no-ops that just return -EINVAL
on an attempt to swapon.

Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

It's possible that we could race with a call to xs_reset_transport, in
which case the xprt->inet pointer could be zeroed out while we're
accessing it. Lock the xprt before we try to set memalloc on it.

Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

We currently increment the memalloc_socks counter if we have a xprt that
is associated with a swapfile. That socket can be replaced however
during a reconnect event, and the memalloc_socks counter is never
decremented if that occurs.

When tearing down a xprt socket, check to see if the xprt is set up for
swapping and sk_clear_memalloc before releasing the socket if so.
Acked-by: NMel Gorman <mgorman@suse.de>
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Split xs_swapper into enable/disable functions and eliminate the
"enable" flag.

Currently, it's racy if you have multiple swapon/swapoff operations
running in parallel over the same xprt. Also fix it so that we only
set it to a memalloc socket on a 0->1 transition and only clear it
on a 1->0 transition.

Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Jerome reported seeing a warning pop when working with a swapfile on
NFS. The nfs_swap_activate can end up calling sk_set_memalloc while
holding the rcu_read_lock and that function can sleep.

To fix that, we need to take a reference to the xprt while holding the
rcu_read_lock, set the socket up for swapping and then drop that
reference. But, xprt_put is not exported and having NFS deal with the
underlying xprt is a bit of layering violation anyway.

Fix this by adding a set of activate/deactivate functions that take a
rpc_clnt pointer instead of an rpc_xprt, and have nfs_swap_activate and
nfs_swap_deactivate call those.

Also, add a per-rpc_clnt atomic counter to keep track of the number of
active swapfiles associated with it. When the counter does a 0->1
transition, we enable swapping on the xprt, when we do a 1->0 transition
we disable swapping on it.

This also allows us to be a bit more selective with the RPC_TASK_SWAPPER
flag. If non-swapper and swapper clnts are sharing a xprt, then we only
need to flag the tasks from the swapper clnt with that flag.
Acked-by: NMel Gorman <mgorman@suse.de>
Reported-by: NJerome Marchand <jmarchan@redhat.com>
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Several functions have outdated arguments listed in the doc comments.
Drop documentation for arguments that no longer exist.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Most code already uses consts for the struct kernel_param_ops,
sweep the kernel for the last offending stragglers. Other than
include/linux/moduleparam.h and kernel/params.c all other changes
were generated with the following Coccinelle SmPL patch. Merge
conflicts between trees can be handled with Coccinelle.

In the future git could get Coccinelle merge support to deal with
patch --> fail --> grammar --> Coccinelle --> new patch conflicts
automatically for us on patches where the grammar is available and
the patch is of high confidence. Consider this a feature request.

Test compiled on x86_64 against:

	* allnoconfig
	* allmodconfig
	* allyesconfig

@ const_found @
identifier ops;
@@

const struct kernel_param_ops ops = {
};

@ const_not_found depends on !const_found @
identifier ops;
@@

-struct kernel_param_ops ops = {
+const struct kernel_param_ops ops = {
};

Generated-by: Coccinelle SmPL
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Junio C Hamano <gitster@pobox.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: cocci@systeme.lip6.fr
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NLuis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

xs_tcp_close() is now just a call to xs_tcp_shutdown(), so remove it,
and replace the entry in xs_tcp_ops.
Suggested-by: NAnna Schumaker <anna.schumaker@netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Yes, kernel_setsockopt() hates you for using a char argument.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Now that the linger code is gone, the xs_tcp_fin_timeout variable has
no real function. Keep it for now, since it is part of the /proc
interface, but only define it if that /proc interface is enabled.
Suggested-by: NAnna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

If the connection reset is due to an active call on our side, then
the state change is sometimes not reported. Catch those instances
using xs_error_report() instead.
Also remove the xs_tcp_shutdown() call in xs_tcp_send_request() as
the change in behaviour makes it redundant.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

Use of socket shutdown() means that we monitor the shutdown process
through the xs_tcp_state_change() callback, so it is preferable to
a full close in all cases unless we're destroying the transport.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

The previous behaviour left the connection half-open in order to try
to scrape the last replies from the socket. Now that we have more reliable
reconnection, change the behaviour to close down the socket faster.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>