SUNRPC: Clean up transport write space handling

Treat socket write space handling in the same way we now treat transport
congestion: by denying the XPRT_LOCK until the transport signals that it
has

SUNRPC: Clean up transport write space handling

Treat socket write space handling in the same way we now treat transport
congestion: by denying the XPRT_LOCK until the transport signals that it
has free buffer space.

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

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SUNRPC: Turn off throttling of RPC slots for TCP sockets

The theory was that we would need to grab the socket lock anyway, so we
might as well use it to gate the allocation of RPC slots for a TCP
so

SUNRPC: Turn off throttling of RPC slots for TCP sockets

The theory was that we would need to grab the socket lock anyway, so we
might as well use it to gate the allocation of RPC slots for a TCP
socket.

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

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SUNRPC: Allow soft RPC calls to time out when waiting for the XPRT_LOCK

This no longer causes them to lose their place in the transmission queue.

Signed-off-by: Trond Myklebust <trond.myklebust@ham

SUNRPC: Allow soft RPC calls to time out when waiting for the XPRT_LOCK

This no longer causes them to lose their place in the transmission queue.

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

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SUNRPC: Allow calls to xprt_transmit() to drain the entire transmit queue

Rather than forcing each and every RPC task to grab the socket write
lock in order to send itself, we allow whichever task i

SUNRPC: Allow calls to xprt_transmit() to drain the entire transmit queue

Rather than forcing each and every RPC task to grab the socket write
lock in order to send itself, we allow whichever task is holding the
write lock to attempt to drain the entire transmit queue.

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

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SUNRPC: Enqueue swapper tagged RPCs at the head of the transmit queue

Avoid memory starvation by giving RPCs that are tagged with the
RPC_TASK_SWAPPER flag the highest priority.

Signed-off-by: Tron

SUNRPC: Enqueue swapper tagged RPCs at the head of the transmit queue

Avoid memory starvation by giving RPCs that are tagged with the
RPC_TASK_SWAPPER flag the highest priority.

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

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SUNRPC: Support for congestion control when queuing is enabled

Both RDMA and UDP transports require the request to get a "congestion control"
credit before they can be transmitted. Right now, this i

SUNRPC: Support for congestion control when queuing is enabled

Both RDMA and UDP transports require the request to get a "congestion control"
credit before they can be transmitted. Right now, this is done when
the request locks the socket. We'd like it to happen when a request attempts
to be transmitted for the first time.
In order to support retransmission of requests that already hold such
credits, we also want to ensure that they get queued first, so that we
don't deadlock with requests that have yet to obtain a credit.

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

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SUNRPC: Improve latency for interactive tasks

One of the intentions with the priority queues was to ensure that no
single process can hog the transport. The field task->tk_owner therefore
identifies

SUNRPC: Improve latency for interactive tasks

One of the intentions with the priority queues was to ensure that no
single process can hog the transport. The field task->tk_owner therefore
identifies the RPC call's origin, and is intended to allow the RPC layer
to organise queues for fairness.
This commit therefore modifies the transmit queue to group requests
by task->tk_owner, and ensures that we round robin among those groups.

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

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SUNRPC: Move RPC retransmission stat counter to xprt_transmit()

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

SUNRPC: Simplify xprt_prepare_transmit()

Remove the checks for whether or not we need to transmit, and whether
or not a reply has been received. Those are already handled in
call_transmit() itself.

SUNRPC: Simplify xprt_prepare_transmit()

Remove the checks for whether or not we need to transmit, and whether
or not a reply has been received. Those are already handled in
call_transmit() itself.

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

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SUNRPC: Don't reset the request 'bytes_sent' counter when releasing XPRT_LOCK

If the request is still on the queue, this will be incorrect behaviour.

Signed-off-by: Trond Myklebust <trond.myklebust

SUNRPC: Don't reset the request 'bytes_sent' counter when releasing XPRT_LOCK

If the request is still on the queue, this will be incorrect behaviour.

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

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SUNRPC: Treat the task and request as separate in the xprt_ops->send_request()

When we shift to using the transmit queue, then the task that holds the
write lock will not necessarily be the same as

SUNRPC: Treat the task and request as separate in the xprt_ops->send_request()

When we shift to using the transmit queue, then the task that holds the
write lock will not necessarily be the same as the one being transmitted.

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

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SUNRPC: Fix up the back channel transmit

Fix up the back channel code to recognise that it has already been
transmitted, so does not need to be called again.
Also ensure that we set req->rq_task.

S

SUNRPC: Fix up the back channel transmit

Fix up the back channel code to recognise that it has already been
transmitted, so does not need to be called again.
Also ensure that we set req->rq_task.

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

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SUNRPC: Refactor RPC call encoding

Move the call encoding so that it occurs before the transport connection
etc.

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

SUNRPC: Add a transmission queue for RPC requests

Add the queue that will enforce the ordering of RPC task transmission.

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

SUNRPC: Distinguish between the slot allocation list and receive queue

When storing a struct rpc_rqst on the slot allocation list, we currently
use the same field 'rq_list' as we use to store the re

SUNRPC: Distinguish between the slot allocation list and receive queue

When storing a struct rpc_rqst on the slot allocation list, we currently
use the same field 'rq_list' as we use to store the request on the
receive queue. Since the structure is never on both lists at the same
time, this is OK.
However, for clarity, let's make that a union with different names for
the different lists so that we can more easily distinguish between
the two states.

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

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SUNRPC: Refactor xprt_transmit() to remove wait for reply code

Allow the caller in clnt.c to call into the code to wait for a reply
after calling xprt_transmit(). Again, the reason is that the backc

SUNRPC: Refactor xprt_transmit() to remove wait for reply code

Allow the caller in clnt.c to call into the code to wait for a reply
after calling xprt_transmit(). Again, the reason is that the backchannel
code does not need this functionality.

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

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SUNRPC: Refactor xprt_transmit() to remove the reply queue code

Separate out the action of adding a request to the reply queue so that the
backchannel code can simply skip calling it altogether.

Si

SUNRPC: Refactor xprt_transmit() to remove the reply queue code

Separate out the action of adding a request to the reply queue so that the
backchannel code can simply skip calling it altogether.

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

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SUNRPC: Rename xprt->recv_lock to xprt->queue_lock

We will use the same lock to protect both the transmit and receive queues.

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

SUNRPC: Don't wake queued RPC calls multiple times in xprt_transmit

Rather than waking up the entire queue of RPC messages a second time,
just wake up the task that was put to sleep.

Signed-off-by:

SUNRPC: Don't wake queued RPC calls multiple times in xprt_transmit

Rather than waking up the entire queue of RPC messages a second time,
just wake up the task that was put to sleep.

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

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SUNRPC: Refactor the transport request pinning

We are going to need to pin for both send and receive.

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

SUNRPC: Simplify identification of when the message send/receive is complete

Add states to indicate that the message send and receive are not yet
complete.

Signed-off-by: Trond Myklebust <trond.myk

SUNRPC: Simplify identification of when the message send/receive is complete

Add states to indicate that the message send and receive are not yet
complete.

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

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SUNRPC: The transmitted message must lie in the RPCSEC window of validity

If a message has been encoded using RPCSEC_GSS, the server is
maintaining a window of sequence numbers that it considers val

SUNRPC: The transmitted message must lie in the RPCSEC window of validity

If a message has been encoded using RPCSEC_GSS, the server is
maintaining a window of sequence numbers that it considers valid.
The client should normally be tracking that window, and needs to
verify that the sequence number used by the message being transmitted
still lies inside the window of validity.

So far, we've been able to assume this condition would be realised
automatically, since the client has been encoding the message only
after taking the socket lock. Once we change that condition, we
will need the explicit check.

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

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SUNRPC: Clean up initialisation of the struct rpc_rqst

Move the initialisation back into xprt.c.

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

sunrpc: whitespace fixes

Remove trailing whitespace and blank line at EOF

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: Prevent duplicate XID allocation

Krzysztof Kozlowski <krzk@kernel.org> reports that a heavy NFSv4
WRITE workload against a slow NFS server causes his Raspberry Pi
clients to stall. Krzysztof

sunrpc: Prevent duplicate XID allocation

Krzysztof Kozlowski <krzk@kernel.org> reports that a heavy NFSv4
WRITE workload against a slow NFS server causes his Raspberry Pi
clients to stall. Krzysztof bisected it to commit 37ac86c3a76c
("SUNRPC: Initialize rpc_rqst outside of xprt->reserve_lock") .

I was able to reproduce similar behavior and it appears that rarely
the RPC client layer is re-allocating an XID for an RPC that it has
already partially sent. This results in the client ignoring the
subsequent reply, which carries the original XID.

For various reasons, checking !req->rq_xmit_bytes_sent in
xprt_prepare_transmit is not a 100% reliable mechanism for
determining when a fresh XID is needed.

Trond's preference is to allocate the XID at the time each rpc_rqst
slot is initialized.

This patch should also address a gcc 4.1.2 complaint reported by
Geert Uytterhoeven <geert@linux-m68k.org>.

Reported-by: Krzysztof Kozlowski <krzk@kernel.org>
Fixes: 37ac86c3a76c ("SUNRPC: Initialize rpc_rqst outside of ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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