There is a race between rpc_info_open and rpc_release_client()
in that nothing stops a process from opening the file after
the clnt->cl_kref goes to zero.

Fix this by using atomic_inc_unless_zero()...
Reported-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

In call_allocate we need to reach the auth in order to factor au_cslack
into the allocation.

As of a17c2153 "SUNRPC: Move the bound
cred to struct rpc_rqst", call_allocate attempts to do this by
dereferencing tk_client->cl_auth, however this is not guaranteed to be
defined--cl_auth can be zero in the case of gss context destruction (see
rpc_free_auth).

Reorder the client state machine to bind credentials before allocating,
so that we can instead reach the auth through the cred.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

This will allow us to save the original generic cred in rpc_message, so
that if we migrate from one server to another, we can generate a new bound
cred without having to punt back to the NFS layer.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Now that rpc_run_task() is the sole entry point for RPC calls, we can move
the remaining rpc_client-related initialisation of struct rpc_task from
sched.c into clnt.c.

Also move rpc_killall_tasks() into the same file, since that too is
relative to the rpc_clnt.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Both rpc_restart_call_prepare() and rpc_restart_call() test for the
RPC_TASK_KILLED flag, and fail to restart the RPC call if that flag is set.

This patch allows callers to know whether or not the restart was
successful, so that they can perform cleanups etc in case of failure.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch removes from net/ (but not any netfilter files)
all the unnecessary return; statements that precede the
last closing brace of void functions.

It does not remove the returns that are immediately
preceded by a label as gcc doesn't like that.

Done via:
$ grep -rP --include=*.[ch] -l "return;\n}" net/ | \
  xargs perl -i -e 'local $/ ; while (<>) { s/\n[ \t\n]+return;\n}/\n}/g; print; }'
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Also have it return an ERR_PTR(-ENOMEM) instead of a null pointer.
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently rpc_run_bc_task() will return NULL if the task allocation failed.
However the only caller is bc_send, which assumes that the return value
will be an ERR_PTR.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Introduce soft connect behavior for UDP transports.  In this case, a
major timeout returns ETIMEDOUT instead of EIO.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, if a remote RPC service is unreachable, an RPC ping will
hang until the underlying transport connect attempt times out.  A more
desirable behavior might be to have the ping fail immediately so upper
layers can recover appropriately.

In the case of an NFS mount, for instance, this would mean the
mount(2) system call could fail immediately if the server isn't
listening, rather than hanging uninterruptibly for more than 3
minutes.

Change rpc_ping() so that it fails immediately for connection-oriented
transports.  rpc_create() will then fail immediately for such
transports if an RPC ping was requested.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Autobinding is handled by the rpciod process, not in user processes
that are generating regular RPC requests.  Thus autobinding is usually
not affected by signals targetting user processes, such as KILL or
timer expiration events.

In addition, an RPC request generated by a user process that has
RPC_TASK_SOFTCONN set and needs to perform an autobind will hang if
the remote rpcbind service is not available.

For rpcbind queries on connection-oriented transports, let's use the
new soft connect semantic to return control to the user's process
quickly, if the kernel's rpcbind client can't connect to the remote
rpcbind service.

Logic is introduced in call_bind_status() to handle connection errors
that occurred during an asynchronous rpcbind query.  The logic
abandons the rpcbind query if the RPC request has SOFTCONN set, and
retries after a few seconds in the normal case.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The kernel sometimes makes RPC calls to services that aren't running.
Because the kernel's RPC client always assumes the hard retry semantic
when reconnecting a connection-oriented RPC transport, the underlying
reconnect logic takes a long while to time out, even though the remote
may have responded immediately with ECONNREFUSED.

In certain cases, like upcalls to our local rpcbind daemon, or for NFS
mount requests, we'd like the kernel to fail immediately if the remote
service isn't reachable.  This allows another transport to be tried
immediately, or the pending request can be abandoned quickly.

Introduce a per-request flag which controls how call_transmit_status()
behaves when request transmission fails because the server cannot be
reached.

We don't want soft connection semantics to apply to other errors.  The
default case of the switch statement in call_transmit_status() no
longer falls through; the fall through code is copied to the default
case, and a "break;" is added.

The transport's connection re-establishment timeout is also ignored for
such requests.  We want the request to fail immediately, so the
reconnect delay is skipped.  Additionally, we don't want a connect
failure here to further increase the reconnect timeout value, since
this request will not be retried.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The success case, where task->tk_status == 0, is by far the most
frequent case in call_transmit_status().

The default: arm of the switch statement in call_transmit_status()
handles the 0 case.  default: was moved close to the top of the switch
statement in call_transmit_status() under the theory that the compiler
places object code for the earliest arms of a switch statement first,
making the CPU do less work.

The default: arm of a switch statement, however, is executed only
after all the other cases have been checked.  Even if the compiler
rearranges the object code, the default: arm is the "last resort",
meaning all of the other cases have been explicitly exhausted.  That
makes the current arrangement about as inefficient as it gets for the
common case.

To fix this, add an explicit check for zero before the switch
statement.  That forces the compiler to do the zero check first, no
matter what optimizations it might try to do to the switch statement.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

DOCPROC Documentation/DocBook/networking.xml
  Warning(net/sunrpc/clnt.c:647): No description found for parameter 'req'
  Warning(net/sunrpc/clnt.c:647): No description found for parameter 'tk_ops'
  Warning(net/sunrpc/clnt.c:647): Excess function parameter 'ops' description in 'rpc_run_bc_task'
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Cc: Benny Halevy <bhalevy@panasas.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

  DOCPROC Documentation/DocBook/networking.xml
  Warning(net/sunrpc/clnt.c:647): No description found for parameter 'req'
  Warning(net/sunrpc/clnt.c:647): No description found for parameter 'tk_ops'
  Warning(net/sunrpc/clnt.c:647): Excess function parameter 'ops' description in 'rpc_run_bc_task'
Signed-off-by: NJaswinder Singh Rajput <jaswinderrajput@gmail.com>
Cc: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Cc: Benny Halevy <bhalevy@panasas.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: David Miller <davem@davemloft.net>
Acked-by: NRandy Dunlap <randy.dunlap@oracle.com>
Acked-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

[sunrpc: change idle timeout value for the backchannel]
Signed-off-by: NAlexandros Batsakis <batsakis@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Acked-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

This patch fixes the bug that was reported in
  http://bugzilla.kernel.org/show_bug.cgi?id=14053

If we're in the case where we need to force a reencode and then resend of
the RPC request, due to xprt_transmit failing with a networking error, then
we _must_ retransmit the entire request.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is still a little wart or two there: Since we've already got a
vfsmount, we might as well pass that in to rpc_create_client_dir.
Another point is that if we open code __rpc_lookup_path() here, then we can
avoid looking up the entire parent directory path over and over again: it
doesn't change.

Also get rid of rpc_clnt->cl_pathname, since it has no users...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This reflects the fact that rpc_mkdir() as it stands today, can only create
a RPC client type directory.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
  It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

  This will make hardirq.h inclusion cheaper for every PREEMPT=n config
  (which includes allmodconfig/allyesconfig, BTW)
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The 'rq_received' member of 'struct rpc_rqst' is used to track when we
have received a reply to our request.  With v4.1, the backchannel
can now accept callback requests over the existing connection.  Rename
this field to make it clear that it is only used for tracking reply bytes
and not all bytes received on the connection.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>

Adds rpc_run_bc_task() which is called by the NFS callback service to
process backchannel requests.  It performs similar work to rpc_run_task()
though "schedules" the backchannel task to be executed starting at the
call_trasmit state in the RPC state machine.

It also introduces some miscellaneous updates to the argument validation,
call_transmit, and transport cleanup functions to take into account
that there are now forechannel and backchannel tasks.

Backchannel requests do not carry an RPC message structure, since the
payload has already been XDR encoded using the existing NFSv4 callback
mechanism.

Introduce a new transmit state for the client to reply on to backchannel
requests.  This new state simply reserves the transport and issues the
reply.  In case of a connection related error, disconnects the transport and
drops the reply.  It requires the forechannel to re-establish the connection
and the server to retransmit the request, as stated in NFSv4.1 section
2.9.2 "Client and Server Transport Behavior".

Note: There is no need to loop attempting to reserve the transport.  If EAGAIN
is returned by xprt_prepare_transmit(), return with tk_status == 0,
setting tk_action to call_bc_transmit.  rpc_execute() will invoke it again
after the task is taken off the sleep queue.

[nfs41: rpc_run_bc_task() need not be exported outside RPC module]
[nfs41: New call_bc_transmit RPC state]
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[nfs41: Backchannel: No need to loop in call_bc_transmit()]
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[rpc_count_iostats incorrectly exits early]
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[Convert rpc_reply_expected() to inline function]
[Remove unnecessary BUG_ON()]
[Rename variable]
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>

Reading and storing the RPC direction is a three step process.

1. xs_tcp_read_calldir() reads the RPC direction, but it will not store it
in the XDR buffer since the 'struct rpc_rqst' is not yet available.

2. The 'struct rpc_rqst' is obtained during the TCP_RCV_COPY_DATA state.
This state need not necessarily be preceeded by the TCP_RCV_READ_CALLDIR.
For example, we may be reading a continuation packet to a large reply.
Therefore, we can't simply obtain the 'struct rpc_rqst' during the
TCP_RCV_READ_CALLDIR state and assume it's available during TCP_RCV_COPY_DATA.

This patch adds a new TCP_RCV_READ_CALLDIR flag to indicate the need to
read the RPC direction.  It then uses TCP_RCV_COPY_CALLDIR to indicate the
RPC direction needs to be saved after the 'struct rpc_rqst' has been allocated.

3. The 'struct rpc_rqst' is obtained by the xs_tcp_read_data() helper
functions.  xs_tcp_read_common() then saves the RPC direction in the XDR
buffer if TCP_RCV_COPY_CALLDIR is set.  This will happen when we're reading
the data immediately after the direction was read.  xs_tcp_read_common()
then clears this flag.

[was nfs41: Skip past the RPC call direction]
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[nfs41: sunrpc: Add RPC direction back into the XDR buffer]
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[nfs41: sunrpc: Don't skip past the RPC call direction]
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>

Signed-off-by: Andy Adamson<andros@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

While we should definitely return socket errors to the task that is
currently trying to send data, there is no need to propagate the same error
to all the other tasks on xprt->pending. Doing so actually slows down
recovery, since it causes more than one tasks to attempt socket recovery.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we get an ECONNREFUSED error, we currently go to sleep on the
'xprt->sending' wait queue. The problem is that no timeout is set there,
and there is nothing else that will wake the task up later.

We should deal with ECONNREFUSED in call_status, given that is where we
also deal with -EHOSTDOWN, and friends.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the socket is unconnected, and xprt_transmit() returns ENOTCONN, we
currently give up the lock on the transport channel. Doing so means that
the lock automatically gets assigned to the next task in the xprt->sending
queue, and so that task needs to be woken up to do the actual connect.

The following patch aims to avoid that unnecessary task switch.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The rpc client needs to know the principal that the setclientid was done
as, so it can tell gssd who to authenticate to.
Signed-off-by: NOlga Kornievskaia <aglo@citi.umich.edu>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Using NIPQUAD() with NIPQUAD_FMT, %d.%d.%d.%d or %u.%u.%u.%u
can be replaced with %pI4
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On a system with nfs mounts, if a task unshares its mount namespace,
a oops can occur when the system is rebooted if the task is the last
to unreference the nfs mount. It will try to create a rpc request
using utsname() which has been invalidated by free_nsproxy().

The patch fixes the issue by using the global init_utsname() which is
always valid. the capability of identifying rpc clients per uts namespace
stills needs some extra work so this should not be a problem.

BUG: unable to handle kernel NULL pointer dereference at 00000004
IP: [<c024c9ab>] rpc_create+0x332/0x42f
Oops: 0000 [#1] DEBUG_PAGEALLOC

Pid: 1857, comm: uts-oops Not tainted (2.6.27-rc5-00319-g7686ad56 #4)
EIP: 0060:[<c024c9ab>] EFLAGS: 00210287 CPU: 0
EIP is at rpc_create+0x332/0x42f
EAX: 00000000 EBX: df26adf0 ECX: c0251887 EDX: 00000001
ESI: df26ae58 EDI: c02f293c EBP: dda0fc9c ESP: dda0fc2c
 DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068
Process uts-oops (pid: 1857, ti=dda0e000 task=dd9a0778 task.ti=dda0e000)
Stack: c0104532 dda0fffc dda0fcac dda0e000 dda0e000 dd93b7f0 00000009 c02f2880
       df26aefc dda0fc68 c01096b7 00000000 c0266ee0 c039a070 c039a070 dda0fc74
       c012ca67 c039a064 dda0fc8c c012cb20 c03daf74 00000011 00000000 c0275c90
Call Trace:
 [<c0104532>] ? dump_trace+0xc2/0xe2
 [<c01096b7>] ? save_stack_trace+0x1c/0x3a
 [<c012ca67>] ? save_trace+0x37/0x8c
 [<c012cb20>] ? add_lock_to_list+0x64/0x96
 [<c0256fc4>] ? rpcb_register_call+0x62/0xbb
 [<c02570c8>] ? rpcb_register+0xab/0xb3
 [<c0252f4d>] ? svc_register+0xb4/0x128
 [<c0253114>] ? svc_destroy+0xec/0x103
 [<c02531b2>] ? svc_exit_thread+0x87/0x8d
 [<c01a75cd>] ? lockd_down+0x61/0x81
 [<c01a577b>] ? nlmclnt_done+0xd/0xf
 [<c01941fe>] ? nfs_destroy_server+0x14/0x16
 [<c0194328>] ? nfs_free_server+0x4c/0xaa
 [<c019a066>] ? nfs_kill_super+0x23/0x27
 [<c0158585>] ? deactivate_super+0x3f/0x51
 [<c01695d1>] ? mntput_no_expire+0x95/0xb4
 [<c016965b>] ? release_mounts+0x6b/0x7a
 [<c01696cc>] ? __put_mnt_ns+0x62/0x70
 [<c0127501>] ? free_nsproxy+0x25/0x80
 [<c012759a>] ? switch_task_namespaces+0x3e/0x43
 [<c01275a9>] ? exit_task_namespaces+0xa/0xc
 [<c0117fed>] ? do_exit+0x4fd/0x666
 [<c01181b3>] ? do_group_exit+0x5d/0x83
 [<c011fa8c>] ? get_signal_to_deliver+0x2c8/0x2e0
 [<c0102630>] ? do_notify_resume+0x69/0x700
 [<c011d85a>] ? do_sigaction+0x134/0x145
 [<c0127205>] ? hrtimer_nanosleep+0x8f/0xce
 [<c0126d1a>] ? hrtimer_wakeup+0x0/0x1c
 [<c0103488>] ? work_notifysig+0x13/0x1b
 =======================
Code: 70 20 68 cb c1 2c c0 e8 75 4e 01 00 8b 83 ac 00 00 00 59 3d 00 f0 ff ff 5f 77 63 eb 57 a1 00 80 2d c0 8b 80 a8 02 00 00 8d 73 68 <8b> 40 04 83 c0 45 e8 41 46 f7 ff ba 20 00 00 00 83 f8 21 0f 4c
EIP: [<c024c9ab>] rpc_create+0x332/0x42f SS:ESP 0068:dda0fc2c
Signed-off-by: NCedric Le Goater <clg@fr.ibm.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

since commit ff7d9756
"nfsd: use static memory for callback program and stats"
do_probe_callback uses a static callback program
(NFS4_CALLBACK) rather than the one set in clp->cl_callback.cb_prog
as passed in by the client in setclientid (4.0)
or create_session (4.1).

This patches introduces rpc_create_args.prognumber that allows
overriding program->number when creating rpc_clnt.
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

If another task is busy in rpcb_getport_async number, it is more efficient
to have it wake us up when it has finished instead of arbitrarily sleeping
for 5 seconds.

Also ensure that rpcb_wake_rpcbind_waiters() is called regardless of
whether or not rpcb_getport_done() gets called.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The cl_chatty flag alows us to control whether a given rpc client leaves

	"server X not responding, timed out"

messages in the syslog.  Such messages make sense for ordinary nfs
clients (where an unresponsive server means applications on the
mountpoint are probably hanging), but not for the callback client (which
can fail more commonly, with the only result just of disabling some
optimizations).

Previously cl_chatty was removed, do to lack of users; reinstate it, and
use it for the nfsd's callback client.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In rpc_show_tasks(), display the program name, version number, procedure
name and tk_action as human-readable variable-length text fields rather
than columnar numbers.

Doing the symbol lookup here helps in cases where we have actual
debugging output from a kernel log, but don't have access to the kernel
image or RPC module that generated the output.

Sample output:

 -pid- flgs status -client- --rqstp- -timeout ---ops--
  5608 0001    -11 eeb42690 f6d93710        0 f8fa1764 nfsv3 WRITE a:call_transmit_status q:none
  5609 0001    -11 eeb42690 f6d937e0        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
  5610 0001    -11 eeb42690 f6d93230        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
  5611 0001    -11 eeb42690 f6d93300        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
  5612 0001    -11 eeb42690 f6d93090        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
  5613 0001    -11 eeb42690 f6d933d0        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
  5614 0001    -11 eeb42690 f6d93cc0        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
  5615 0001    -11 eeb42690 f6d93a50        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
  5616 0001    -11 eeb42690 f6d93640        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
  5617 0001    -11 eeb42690 f6d93b20        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
  5618 0001    -11 eeb42690 f6d93160        0 f8fa1764 nfsv3 WRITE a:call_status q:xprt_sending
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: move the logic that displays each task to its own function.
This removes indentation and makes future changes easier.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up: don't display the rpc_show_tasks column header unless there is at
least one task to display.  As far as I can tell, it is safe to let the
list_for_each_entry macro decide that each list is empty.

scripts/checkpatch.pl also wants a KERN_FOO at the start of any newly added
printk() calls, so this and subsequent patches will also add KERN_INFO.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>