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A single RPC transaction that touches only a couple of pages means
rq_pvec will not be even close to full in svc_xpt_release(). This is
a common case.
Instead, just leave the pages in rq_pvec until it is completely
full. This improves the efficiency of the batch release mechanism
on workloads that involve small RPC messages.
The rq_pvec is also fully emptied just before thread exit.
Reviewed-by: Calum Mackay <calum.mackay@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Instead of invoking put_page() one-at-a-time, pass the "response"
portion of rq_pages directly to release_pages() to reduce the number
of times each nfsd thread invokes a page allocator API.
Since svc_xprt_release() is not invoked while a client is waiting
for an RPC Reply, this is not expected to directly impact mean
request latencies on a lightly or moderately loaded server. However
as workload intensity increases, I expect somewhat better
scalability: the same number of server threads should be able to
handle more work.
Reviewed-by: Calum Mackay <calum.mackay@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Clean-up: There doesn't seem to be a reason why this function is
stuck in a header. One thing it prevents is the convenient addition
of tracing. Moving it to a source file also makes the rq_respages
clean-up logic easier to find.
Reviewed-by: Calum Mackay <calum.mackay@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Clean up: All callers of svc_process() ignore its return value, so
svc_process() can safely be converted to return void. Ditto for
svc_send().
The return value of ->xpo_sendto() is now used only as part of a
trace event.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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There have been several bugs over the years where the NFSD splice
actor has attempted to write outside the rq_pages array.
This is a "should never happen" condition, but if for some reason
the pipe splice actor should attempt to walk past the end of
rq_pages, it needs to terminate the READ operation to prevent
corruption of the pointer addresses in the fields just beyond the
array.
A server crash is thus prevented. Since the code is not behaving,
the READ operation returns -EIO to the client. None of the READ
payload data can be trusted if the splice actor isn't operating as
expected.
Suggested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
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Fix a race where kthread_stop() may prevent the threadfn from ever getting
called. If that happens the svc_rqst will not be cleaned up.
Fixes: ed6473ddc704 ("NFSv4: Fix callback server shutdown")
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Eliminate the use of bus-locked operations in svc_xprt_enqueue(),
which is a hot path. Replace them with per-cpu variables to reduce
cross-CPU memory bus traffic.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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- Improves counting accuracy
- Reduces cross-CPU memory traffic
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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To navigate around the space that svcauth_gss_accept() reserves
for the RPC payload body length and sequence number fields,
svcauth_gss_release() does a little dance with the reply's
accept_stat, moving the accept_stat value in the response buffer
down by two words.
Instead, let's have the ->accept() methods each set the proper
final location of the accept_stat to avoid having to move
things.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Currently, svcauth_gss_accept() pre-reserves response buffer space
for the RPC payload length and GSS sequence number before returning
to the dispatcher, which then adds the header's accept_stat field.
The problem is the accept_stat field is supposed to go before the
length and seq_num fields. So svcauth_gss_release() has to relocate
the accept_stat value (see svcauth_gss_prepare_to_wrap()).
To enable these fields to be added to the response buffer in the
correct (final) order, the pointer to the accept_stat has to be made
available to svcauth_gss_accept() so that it can set it before
reserving space for the length and seq_num fields.
As a first step, move the pointer to the location of the accept_stat
field into struct svc_rqst.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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The @resv parameter is no longer used.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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The main part of RPC header encoding and the formation of error
responses are now done using the xdr_stream helpers. Bounds checking
before each XDR data item is encoded makes the server's encoding
path safer against accidental buffer overflows.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Now that each ->accept method has been converted, the
svcxdr_init_encode() calls can be hoisted back up into the generic
RPC server code.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Refactor: So that the overhaul of each ->accept method can be done
in separate smaller patches, temporarily move the
svcxdr_init_encode() call into those methods.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Now that all vs_dispatch functions invoke svcxdr_init_encode(), it
is common code and can be pushed down into the generic RPC server.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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There's no RPC header field called rpc_stat; more precisely, the
variable appears to be recording an accept_stat value. But it looks
like we don't need to preserve this value at all, actually, so
simply remove the variable.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Now the entire RPC Call header parsing path is handled via struct
xdr_stream-based decoders.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Clean up: With xdr_stream decoding, the @argv parameter is no longer
used.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Done as part of hardening the server-side RPC header decoding path.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Clean up: Saving the RPC program number in two places is
unnecessary.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Clean up: Group these together for legibility.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Now that each ->accept method has been converted to use xdr_stream,
the svcxdr_init_decode() calls can be hoisted back up into the
generic RPC server code.
The dprintk in svc_authenticate() is removed, since
trace_svc_authenticate() reports the same information.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Refactor: So that the overhaul of each ->accept method can be done
in separate smaller patches, temporarily move the
svcxdr_init_decode() call into those methods.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Now that all vs_dispatch functions invoke svcxdr_init_decode(), it
is common code and can be pushed down into the generic RPC server.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux
Pull nfsd fixes from Chuck Lever:
- Fix a race when creating NFSv4 files
- Revert the use of relaxed bitops
* tag 'nfsd-6.2-3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
NFSD: Use set_bit(RQ_DROPME)
Revert "SUNRPC: Use RMW bitops in single-threaded hot paths"
nfsd: fix handling of cached open files in nfsd4_open codepath
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The premise that "Once an svc thread is scheduled and executing an
RPC, no other processes will touch svc_rqst::rq_flags" is false.
svc_xprt_enqueue() examines the RQ_BUSY flag in scheduled nfsd
threads when determining which thread to wake up next.
Found via KCSAN.
Fixes: 28df0988815f ("SUNRPC: Use RMW bitops in single-threaded hot paths")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Due to several bugs caused by timers being re-armed after they are
shutdown and just before they are freed, a new state of timers was added
called "shutdown". After a timer is set to this state, then it can no
longer be re-armed.
The following script was run to find all the trivial locations where
del_timer() or del_timer_sync() is called in the same function that the
object holding the timer is freed. It also ignores any locations where
the timer->function is modified between the del_timer*() and the free(),
as that is not considered a "trivial" case.
This was created by using a coccinelle script and the following
commands:
$ cat timer.cocci
@@
expression ptr, slab;
identifier timer, rfield;
@@
(
- del_timer(&ptr->timer);
+ timer_shutdown(&ptr->timer);
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- del_timer_sync(&ptr->timer);
+ timer_shutdown_sync(&ptr->timer);
)
... when strict
when != ptr->timer
(
kfree_rcu(ptr, rfield);
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kmem_cache_free(slab, ptr);
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kfree(ptr);
)
$ spatch timer.cocci . > /tmp/t.patch
$ patch -p1 < /tmp/t.patch
Link: https://lore.kernel.org/lkml/20221123201306.823305113@linutronix.de/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Pavel Machek <pavel@ucw.cz> [ LED ]
Acked-by: Kalle Valo <kvalo@kernel.org> [ wireless ]
Acked-by: Paolo Abeni <pabeni@redhat.com> [ networking ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Clean up: Simplify the tracepoint's only call site.
Also, I noticed that when svc_authenticate() returns SVC_COMPLETE,
it leaves rq_auth_stat set to an error value. That doesn't need to
be recorded in the trace log.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
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Clean up after commit 22700f3c6df5 ("SUNRPC: Improve ordering of
transport processing").
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Note the function returns a per-transport value, not a per-request
value (eg, one that is related to the size of the available send or
receive buffer space).
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Currently, SUNRPC clears the whole of .pc_argsize before processing
each incoming RPC transaction. Add an extra parameter to struct
svc_procedure to enable upper layers to reduce the amount of each
operation's argument structure that is zeroed by SUNRPC.
The size of struct nfsd4_compoundargs, in particular, is a lot to
clear on each incoming RPC Call. A subsequent patch will cut this
down to something closer to what NFSv2 and NFSv3 uses.
This patch should cause no behavior changes.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Move exception handling code out of the hot path, and avoid the need
for a bswap of a non-constant.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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I noticed CPU pipeline stalls while using perf.
Once an svc thread is scheduled and executing an RPC, no other
processes will touch svc_rqst::rq_flags. Thus bus-locked atomics are
not needed outside the svc thread scheduler.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Clean up: There is one caller. The @cpu argument can be made
implicit now that a get_cpu/put_cpu pair is no longer needed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Hoist svo_function back into svc_serv and remove struct
svc_serv_ops, since the struct is now devoid of fields.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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struct svc_serv_ops is about to be removed.
Neil Brown says:
> I suspect svo_module can go as well - I don't think the thread is
> ever the thing that primarily keeps a module active.
A random sample of kthread_create() callers shows sunrpc is the only
one that manages module reference count in this way.
Suggested-by: Neil Brown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Clean up: svc_shutdown_net() now does nothing but call
svc_close_net(). Replace all external call sites.
svc_close_net() is renamed to be the inverse of svc_xprt_create().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Clean up: Use the "svc_xprt_<task>" function naming convention as
is used for other external APIs.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Clean up. Neil observed that "any code that calls svc_shutdown_net()
knows what the shutdown function should be, and so can call it
directly."
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: NeilBrown <neilb@suse.de>
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svc_set_num_threads() does everything that lockd_start_svc() does, except
set sv_maxconn. It also (when passed 0) finds the threads and
stops them with kthread_stop().
So move the setting for sv_maxconn, and use svc_set_num_thread()
We now don't need nlmsvc_task.
Now that we use svc_set_num_threads() it makes sense to set svo_module.
This request that the thread exists with module_put_and_exit().
Also fix the documentation for svo_module to make this explicit.
svc_prepare_thread is now only used where it is defined, so it can be
made static.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Currently 'pooled' services hold a reference on the pool_map, and
'unpooled' services do not.
svc_destroy() uses the presence of ->svo_function (via
svc_serv_is_pooled()) to determine if the reference should be dropped.
There is no direct correlation between being pooled and the use of
svo_function, though in practice, lockd is the only non-pooled service,
and the only one not to use svo_function.
This is untidy and would cause problems if we changed lockd to use
svc_set_num_threads(), which requires the use of ->svo_function.
So change the test for "is the service pooled" to "is sv_nrpools > 1".
This means that when svc_pool_map_get() returns 1, it must NOT take a
reference to the pool.
We discard svc_serv_is_pooled(), and test sv_nrpools directly.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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These definitions are not used outside of svc.c, and there is no
evidence that they ever have been. So move them into svc.c
and make the declarations 'static'.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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The ->svo_setup callback serves no purpose. It is always called from
within the same module that chooses which callback is needed. So
discard it and call the relevant function directly.
Now that svc_set_num_threads() is no longer used remove it and rename
svc_set_num_threads_sync() to remove the "_sync" suffix.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Using sv_lock means we don't need to hold the service mutex over these
updates.
In particular, svc_exit_thread() no longer requires synchronisation, so
threads can exit asynchronously.
Note that we could use an atomic_t, but as there are many more read
sites than writes, that would add unnecessary noise to the code.
Some reads are already racy, and there is no need for them to not be.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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The use of sv_nrthreads as a general refcount results in clumsy code, as
is seen by various comments needed to explain the situation.
This patch introduces a 'struct kref' and uses that for reference
counting, leaving sv_nrthreads to be a pure count of threads. The kref
is managed particularly in svc_get() and svc_put(), and also nfsd_put();
svc_destroy() now takes a pointer to the embedded kref, rather than to
the serv.
nfsd allows the svc_serv to exist with ->sv_nrhtreads being zero. This
happens when a transport is created before the first thread is started.
To support this, a 'keep_active' flag is introduced which holds a ref on
the svc_serv. This is set when any listening socket is successfully
added (unless there are running threads), and cleared when the number of
threads is set. So when the last thread exits, the nfs_serv will be
destroyed.
The use of 'keep_active' replaces previous code which checked if there
were any permanent sockets.
We no longer clear ->rq_server when nfsd() exits. This was done
to prevent svc_exit_thread() from calling svc_destroy().
Instead we take an extra reference to the svc_serv to prevent
svc_destroy() from being called.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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svc_destroy() is poorly named - it doesn't necessarily destroy the svc,
it might just reduce the ref count.
nfsd_destroy() is poorly named for the same reason.
This patch:
- removes the refcount functionality from svc_destroy(), moving it to
a new svc_put(). Almost all previous callers of svc_destroy() now
call svc_put().
- renames nfsd_destroy() to nfsd_put() and improves the code, using
the new svc_destroy() rather than svc_put()
- removes a few comments that explain the important for balanced
get/put calls. This should be obvious.
The only non-trivial part of this is that svc_destroy() would call
svc_sock_update() on a non-final decrement. It can no longer do that,
and svc_put() isn't really a good place of it. This call is now made
from svc_exit_thread() which seems like a good place. This makes the
call *before* sv_nrthreads is decremented rather than after. This
is not particularly important as the call just sets a flag which
causes sv_nrthreads set be checked later. A subsequent patch will
improve the ordering.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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There was some spaghetti in svc_process_common() that had evolved
over time such that there was still one case that needed a call
to .pc_release() but never made it. That issue was removed in
the previous patch.
As additional insurance against missing this important callout,
ensure that the .pc_release() method is always called, no matter
what the reply_stat is.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Micro-optimization: The last user of the generic SVC dispatch code
path has been removed, so svc_process_common() can be simplified.
This declutters the hot path so that the by-far most common case
(a dispatch function exists) is made the /only/ path.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Refactor.
Now that the NFSv2 and NFSv3 XDR decoders have been converted to
use xdr_streams, the WRITE decoder functions can use
xdr_stream_subsegment() to extract the WRITE payload into its own
xdr_buf, just as the NFSv4 WRITE XDR decoder currently does.
That makes it possible to pass the first kvec, pages array + length,
page_base, and total payload length via a single function parameter.
The payload's page_base is not yet assigned or used, but will be in
subsequent patches.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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Pull NFS client updates from Anna Schumaker:
"New Features:
- Better client responsiveness when server isn't replying
- Use refcount_t in sunrpc rpc_client refcount tracking
- Add srcaddr and dst_port to the sunrpc sysfs info files
- Add basic support for connection sharing between servers with multiple NICs`
Bugfixes and Cleanups:
- Sunrpc tracepoint cleanups
- Disconnect after ib_post_send() errors to avoid deadlocks
- Fix for tearing down rpcrdma_reps
- Fix a potential pNFS layoutget livelock loop
- pNFS layout barrier fixes
- Fix a potential memory corruption in rpc_wake_up_queued_task_set_status()
- Fix reconnection locking
- Fix return value of get_srcport()
- Remove rpcrdma_post_sends()
- Remove pNFS dead code
- Remove copy size restriction for inter-server copies
- Overhaul the NFS callback service
- Clean up sunrpc TCP socket shutdowns
- Always provide aligned buffers to RPC read layers"
* tag 'nfs-for-5.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (39 commits)
NFS: Always provide aligned buffers to the RPC read layers
NFSv4.1 add network transport when session trunking is detected
SUNRPC enforce creation of no more than max_connect xprts
NFSv4 introduce max_connect mount options
SUNRPC add xps_nunique_destaddr_xprts to xprt_switch_info in sysfs
SUNRPC keep track of number of transports to unique addresses
NFSv3: Delete duplicate judgement in nfs3_async_handle_jukebox
SUNRPC: Tweak TCP socket shutdown in the RPC client
SUNRPC: Simplify socket shutdown when not reusing TCP ports
NFSv4.2: remove restriction of copy size for inter-server copy.
NFS: Clean up the synopsis of callback process_op()
NFS: Extract the xdr_init_encode/decode() calls from decode_compound
NFS: Remove unused callback void decoder
NFS: Add a private local dispatcher for NFSv4 callback operations
SUNRPC: Eliminate the RQ_AUTHERR flag
SUNRPC: Set rq_auth_stat in the pg_authenticate() callout
SUNRPC: Add svc_rqst::rq_auth_stat
SUNRPC: Add dst_port to the sysfs xprt info file
SUNRPC: Add srcaddr as a file in sysfs
sunrpc: Fix return value of get_srcport()
...
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