None of the callers set the 'action' argument, so let's just remove it.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

rpc_sleep_on() does not need to set the task->tk_callback under the
queue lock, so move that out.
Also refactor the check for whether the task is active.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Convert the transport callback to actually put the request to sleep
instead of just setting a timeout. This is in preparation for
rpc_sleep_on_timeout().
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The RPC_TASK_KILLED flag should really not be set from another context
because it can clobber data in the struct task when task->tk_flags is
changed non-atomically.
Let's therefore swap out RPC_TASK_KILLED with an atomic flag, and add
a function to set that flag and safely wake up the task.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

If a request transmission fails due to write space or slot unavailability
errors, but the queued task then gets transmitted before it has time to
process the error in call_transmit_status() or call_bc_transmit_status(),
we need to suppress the transmission error code to prevent it from leaking
out of the RPC layer.
Reported-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: NChuck Lever <chuck.lever@oracle.com>

This reverts commit 009a82f6.

The ability to optimise here relies on compiler being able to optimise
away tail calls to avoid stack overflows. Unfortunately, we are seeing
reports of problems, so let's just revert.
Reported-by: NDaniel Mack <daniel@zonque.org>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

We want to drain only the RQ first. Otherwise the transport can
deadlock on ->close if there are outstanding Send completions.

Fixes: 6d2d0ee2 ("xprtrdma: Replace rpcrdma_receive_wq ... ")
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org # v5.0+
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Avoid following compiler warning on uninitialized variable

net/sunrpc/xprtsock.c: In function ‘xs_read_stream_request.constprop’:
net/sunrpc/xprtsock.c:525:10: warning: ‘read’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   return read;
          ^~~~
net/sunrpc/xprtsock.c:529:23: warning: ‘ret’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  return ret < 0 ? ret : read;
         ~~~~~~~~~~~~~~^~~~~~
Signed-off-by: NAlakesh Haloi <alakesh.haloi@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If the transport is still connected, then we do want to allow
RPC_SOFTCONN tasks to retry. They should time out if and only if
the connection is broken.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Now that we're using the xdr_stream functions to decode the header,
the test for the minimum reply length is redundant.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Handle the SYSTEM_ERR rpc error by retrying the RPC call as if it
were a garbage argument.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Ensure that when the "garbage args" case falls through, we do set
an error of EIO.

Fixes: a0584ee9 ("SUNRPC: Use struct xdr_stream when decoding...")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

When the socket is closed, we currently send an EAGAIN error to all
pending requests in order to ask them to retransmit. Use ENOTCONN
instead, to ensure that they try to reconnect before attempting to
transmit.
This also helps SOFTCONN tasks to behave correctly in this
situation.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

We must at minimum allocate enough memory to be able to see any auth
errors in the reply from the server.

Fixes: 2c94b8ec ("SUNRPC: Use au_rslack when computing reply...")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If the server sends a reply that is larger than the pre-allocated
buffer, then the current code may fail to register how much of
the stream that it has finished reading. This again can lead to
hangs.

Fixes: e92053a5 ("SUNRPC: Handle zero length fragments correctly")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Before trying to bind a port, ensure we grab the send lock to
ensure that we don't change the port while another task is busy
transmitting requests.
The connect code already takes the send lock in xprt_connect(),
but it is harmless to take it before that.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

In cases where we know the task is not sleeping, try to optimise
away the indirect call to task->tk_action() by replacing it with
a direct call.
Only change tail calls, to allow gcc to perform tail call
elimination.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Before initiating transport actions that require putting the task to sleep,
such as rebinding or reconnecting, we should check whether or not the task
was already transmitted.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

The RPC task wakeup calls all check for RPC_IS_QUEUED() before taking any
locks. In addition, rpc_exit() already calls rpc_wake_up_queued_task().
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Replace remaining callers of call_timeout() with rpc_check_timeout().
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Fix a regression where soft and softconn requests are not timing out
as expected.

Fixes: 89f90fe1 ("SUNRPC: Allow calls to xprt_transmit() to drain...")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Now that transmissions happen through a queue, we require the RPC tasks
to handle error conditions that may have been set while they were
sleeping. The back channel does not currently do this, but assumes
that any error condition happens during its own call to xprt_transmit().

The solution is to ensure that the back channel splits out the
error handling just like the forward channel does.

Fixes: 89f90fe1 ("SUNRPC: Allow calls to xprt_transmit() to drain...")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If the socket is not connected, then we want to initiate a reconnect
rather that trying to transmit requests. If there is a large number
of requests queued and waiting for the lock in call_transmit(),
then it can take a while for one of the to loop back and retake
the lock in call_connect.

Fixes: 89f90fe1 ("SUNRPC: Allow calls to xprt_transmit() to drain...")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Now that the reads happen in a process context rather than a softirq,
it is safe to allocate back channel slots using a reclaiming
allocation.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Convert the remaining gfp_flags arguments in sunrpc to standard reclaiming
allocations, now that we set memalloc_nofs_save() as appropriate.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If a layout segment gets invalidated while a pNFS I/O operation
is queued for transmission, then we ideally want to abort
immediately. This is particularly the case when there is a large
number of I/O related RPCs queued in the RPC layer, and the layout
segment gets invalidated due to an ENOSPC error, or an EACCES (because
the client was fenced). We may end up forced to spam the MDS with a
lot of otherwise unnecessary LAYOUTERRORs after that I/O fails.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

udp_poll() checks the struct file for the O_NONBLOCK flag, so we must not
call it with a NULL file pointer.

Fixes: 0ffe86f4 ("SUNRPC: Use poll() to fix up the socket requeue races")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

James Pearson found that an NFS server stopped responding to UDP
requests if started with more than 1017 threads.

sv_max_mesg is about 2^20, so that is probably where the calculation
performed by

	svc_sock_setbufsize(svsk->sk_sock,
                            (serv->sv_nrthreads+3) * serv->sv_max_mesg,
                            (serv->sv_nrthreads+3) * serv->sv_max_mesg);

starts to overflow an int.
Reported-by: NJames Pearson <jcpearson@gmail.com>
Tested-by: NJames Pearson <jcpearson@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

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

Now that we send the pages using a struct msghdr, instead of
using sendpage(), we no longer need to 'prime the socket' with
an address for unconnected UDP messages.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Simplify the page send code using iov_iter and bvecs.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Prepare to the socket transmission code to use iov_iter.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If the client stream receive code receives an ESHUTDOWN error either
because the server closed the connection, or because it sent a
callback which cannot be processed, then we should shut down
the connection.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If the message read completes, but the socket returned an error
condition, we should ensure to propagate that error.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

A zero length fragment is really a bug, but let's ensure we don't
go nuts when one turns up.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

To ensure that the receive worker has exclusive access to the stream record
info, we must not reset the contents other than when holding the
transport->recv_mutex.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

As reported by Dan Carpenter, this test for acred->cred being set is
inconsistent with the dereference of the pointer a few lines earlier.

An 'auth_cred' *always* has ->cred set - every place that creates one
initializes this field, often as the first thing done.

So remove this test.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

When we resend a request, ensure that the 'rq_bytes_sent' is reset
to zero.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Because we clear XPRT_SOCK_DATA_READY before reading, we can end up
with a situation where new data arrives, causing xs_data_ready() to
queue up a second receive worker job for the same socket, which then
immediately gets stuck waiting on the transport receive mutex.
The fix is to only clear XPRT_SOCK_DATA_READY once we're done reading,
and then to use poll() to check if we might need to queue up a new
job in order to deal with any new data.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>