The use of the bitmaps is confusing.  Add a cross-reference to make it
easier to find the existing comment.  Add an updated reference with URL
to make it quicker to look up.  And a bit more editorializing about the
value of this.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up: The garbage_args and cant_encode tracepoints report the
same information as each other, so combine them into a single
tracepoint class to reduce code duplication and slightly reduce the
size of trace.o.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

I'm about to add more information to the server-side SUNRPC
tracepoints, so I'm going to offset the increased trace log
consumption by getting rid of some tracepoints that fire frequently
but don't offer much value.

trace_svc_xprt_received() was useful for debugging, perhaps, but
is not generally informative.

trace_svc_handle_xprt() reports largely the same information as
trace_svc_xdr_recvfrom().

As a clean-up, rename trace_svc_xprt_do_enqueue() to match
svc_xprt_dequeue().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

We currently have a 'laundrette' for closing cached files - a different
work-item for each network-namespace.

These 'laundrettes' (aka struct nfsd_fcache_disposal) are currently on a
list, and are freed using rcu.

The list is not necessary as we have a per-namespace structure (struct
nfsd_net) which can hold a link to the nfsd_fcache_disposal.
The use of kfree_rcu is also unnecessary as the cache is cleaned of all
files associated with a given namespace, and no new files can be added,
before the nfsd_fcache_disposal is freed.

So add a '->fcache_disposal' link to nfsd_net, and discard the list
management and rcu usage.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Eliminate the follow smatch warning:

fs/nfsd/nfs4xdr.c:4766 nfsd4_encode_read_plus_hole() warn: inconsistent
indenting.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Commit 7142b98d ("nfsd: Clean up drc cache in preparation for
global spinlock elimination"), billed as a clean-up, added
be32_to_cpu() to the DRC hash function without explanation. That
commit removed two comments that state that byte-swapping in the
hash function is unnecessary without explaining whether there was
a need for that change.

On some Intel CPUs, the swab32 instruction is known to cause a CPU
pipeline stall. be32_to_cpu() does not add extra randomness, since
the hash multiplication is done /before/ shifting to the high-order
bits of the result.

As a micro-optimization, remove the unnecessary transform from the
DRC hash function.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Now that thread management is consistent there is no need for
nfs-callback to use svc_create_pooled() as introduced in Commit
df807fff ("NFSv4.x/callback: Create the callback service through
svc_create_pooled").  So switch back to svc_create().

If service pools were configured, but the number of threads were left at
'1', nfs callback may not work reliably when svc_create_pooled() is used.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

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>

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>

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>

lockd_create_svc() already does an svc_get() if the service already
exists, so it is more like a "get" than a "create".

So:
 - Move the increment of nlmsvc_users into the function as well
 - rename to lockd_get().

It is now the inverse of lockd_put().
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

There is some cleanup that is duplicated in lockd_down() and the failure
path of lockd_up().
Factor these out into a new lockd_put() and call it from both places.

lockd_put() does *not* take the mutex - that must be held by the caller.
It decrements nlmsvc_users and if that reaches zero, it cleans up.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

The normal place to call svc_exit_thread() is from the thread itself
just before it exists.
Do this for lockd.

This means that nlmsvc_rqst is not used out side of lockd_start_svc(),
so it can be made local to that function, and renamed to 'rqst'.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

lockd_start_svc() only needs to be called once, just after the svc is
created.  If the start fails, the svc is discarded too.

It thus makes sense to call lockd_start_svc() from lockd_create_svc().
This allows us to remove the test against nlmsvc_rqst at the start of
lockd_start_svc() - it must always be NULL.

lockd_up() only held an extra reference on the svc until a thread was
created - then it dropped it.  The thread - and thus the extra reference
- will remain until kthread_stop() is called.
Now that the thread is created in lockd_create_svc(), the extra
reference can be dropped there.  So the 'serv' variable is no longer
needed in lockd_up().
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Now that the network status notifiers use nlmsvc_serv rather then
nlmsvc_rqst the management can be simplified.

Notifier unregistration synchronises with any pending notifications so
providing we unregister before nlm_serv is freed no further interlock
is required.

So we move the unregister call to just before the thread is killed
(which destroys the service) and just before the service is destroyed in
the failure-path of lockd_up().

Then nlm_ntf_refcnt and nlm_ntf_wq can be removed.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

lockd has two globals - nlmsvc_task and nlmsvc_rqst - but mostly it
wants the 'struct svc_serv', and when it doesn't want it exactly it can
get to what it wants from the serv.

This patch is a first step to removing nlmsvc_task and nlmsvc_rqst.  It
introduces nlmsvc_serv to store the 'struct svc_serv*'.  This is set as
soon as the serv is created, and cleared only when it is destroyed.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

nfsd currently maintains an open-coded read/write semaphore (refcount
and wait queue) for each network namespace to ensure the nfs service
isn't shut down while the notifier is running.

This is excessive.  As there is unlikely to be contention between
notifiers and they run without sleeping, a single spinlock is sufficient
to avoid problems.
Signed-off-by: NeilBrown <neilb@suse.de>
[ cel: ensure nfsd_notifier_lock is static ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

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>

nfsd cannot currently use svc_set_num_threads_sync.  It instead
uses svc_set_num_threads which does *not* wait for threads to all
exit, and has a separate mechanism (nfsd_shutdown_complete) to wait
for completion.

The reason that nfsd is unlike other services is that nfsd threads can
exit separately from svc_set_num_threads being called - they die on
receipt of SIGKILL.  Also, when the last thread exits, the service must
be shut down (sockets closed).

For this, the nfsd_mutex needs to be taken, and as that mutex needs to
be held while svc_set_num_threads is called, the one cannot wait for
the other.

This patch changes the nfsd thread so that it can drop the ref on the
service without blocking on nfsd_mutex, so that svc_set_num_threads_sync
can be used:
 - if it can drop a non-last reference, it does that.  This does not
   trigger shutdown and does not require a mutex.  This will likely
   happen for all but the last thread signalled, and for all threads
   being shut down by nfsd_shutdown_threads()
 - if it can get the mutex without blocking (trylock), it does that
   and then drops the reference.  This will likely happen for the
   last thread killed by SIGKILL
 - Otherwise there might be an unrelated task holding the mutex,
   possibly in another network namespace, or nfsd_shutdown_threads()
   might be just about to get a reference on the service, after which
   we can drop ours safely.
   We cannot conveniently get wakeup notifications on these events,
   and we are unlikely to need to, so we sleep briefly and check again.

With this we can discard nfsd_shutdown_complete and
nfsd_complete_shutdown(), and switch to svc_set_num_threads_sync.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

There is nothing happening in the start of nfsd() that requires
protection by the mutex, so don't take it until shutting down the thread
- which does still require protection - but only for nfsd_put().
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

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>

This allows us to move the updates for th_cnt out of the mutex.
This is a step towards reducing mutex coverage in nfsd().
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

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>

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>

It is common for 'get' functions to return the object that was 'got',
and there are a couple of places where users of svc_get() would be a
little simpler if svc_get() did that.

Make it so.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

If write_ports_add() fails, we shouldn't destroy the serv, unless we had
only just created it.  So if there are any permanent sockets already
attached, leave the serv in place.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

/home/cel/src/linux/linux/fs/nfsd/nfs4proc.c:1539:24: warning: incorrect type in assignment (different base types)
/home/cel/src/linux/linux/fs/nfsd/nfs4proc.c:1539:24:    expected restricted __be32 [usertype] status
/home/cel/src/linux/linux/fs/nfsd/nfs4proc.c:1539:24:    got int
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Pull USB fixes from Greg KH:
 "Here are some small USB fixes for 5.16-rc5.  They include:

   - gadget driver fixes for reported issues

   - xhci fixes for reported problems.

   - config endpoint parsing fixes for where we got bitfields wrong

  Most of these have been in linux-next, the remaining few were not, but
  got lots of local testing in my systems and in some cloud testing
  infrastructures"

* tag 'usb-5.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: core: config: using bit mask instead of individual bits
  usb: core: config: fix validation of wMaxPacketValue entries
  USB: gadget: zero allocate endpoint 0 buffers
  USB: gadget: detect too-big endpoint 0 requests
  xhci: avoid race between disable slot command and host runtime suspend
  xhci: Remove CONFIG_USB_DEFAULT_PERSIST to prevent xHCI from runtime suspending
  Revert "usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default"

Pull char/misc driver fixes from Greg KH:
 "Here are a bunch of small char/misc and other driver subsystem fixes.

  Included in here are:

   - iio driver fixes for reported problems

   - phy driver fixes for a number of reported problems

   - mhi resume bugfix for broken hardware

   - nvmem driver fix

   - rtsx driver fix for irq issues

   - fastrpc packet parsing fix

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-5.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (33 commits)
  bus: mhi: core: Add support for forced PM resume
  iio: trigger: stm32-timer: fix MODULE_ALIAS
  misc: rtsx: Avoid mangling IRQ during runtime PM
  nvmem: eeprom: at25: fix FRAM byte_len
  misc: fastrpc: fix improper packet size calculation
  MAINTAINERS: add maintainer for Qualcomm FastRPC driver
  bus: mhi: pci_generic: Fix device recovery failed issue
  iio: adc: stm32: fix null pointer on defer_probe error
  phy: HiSilicon: Fix copy and paste bug in error handling
  dt-bindings: phy: zynqmp-psgtr: fix USB phy name
  phy: ti: omap-usb2: Fix the kernel-doc style
  phy: qualcomm: ipq806x-usb: Fix kernel-doc style
  iio: at91-sama5d2: Fix incorrect sign extension
  iio: adc: axp20x_adc: fix charging current reporting on AXP22x
  iio: gyro: adxrs290: fix data signedness
  phy: ti: tusb1210: Fix the kernel-doc warn
  phy: qualcomm: usb-hsic: Fix the kernel-doc warn
  phy: qualcomm: qmp: Add missing struct documentation
  phy: mvebu-cp110-utmi: Fix kernel-doc warns
  iio: ad7768-1: Call iio_trigger_notify_done() on error
  ...

Pull timer fixes from Thomas Gleixner:
 "Two fixes for clock chip drivers:

   - A regression fix for the Designware APB timer. A recent change to
     the error checking code transformed the error condition wrongly so
     it turned into a fail if good condition.

   - Fix a clang build fail of the ARM architected timer driver"

* tag 'timers-urgent-2021-12-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/drivers/arm_arch_timer: Force inlining of erratum_set_next_event_generic()
  clocksource/drivers/dw_apb_timer_of: Fix probe failure

Pull irq fixes from Thomas Gleixner:
 "A set of interrupt chip driver fixes:

   - Fix the multi vector MSI allocation on Armada 370XP

   - Do interrupt acknowledgement correctly in the aspeed-scu driver

   - Make the IPR register offset correct in the NVIC driver

   - Make redistribution table flushing correct by issueing a SYNC
     command to ensure that the invalidation command has been executed

   - Plug a device tree node reference leak in the bcm7210-l2 driver

   - Trivial fixes in the MIPS GIC and the Apple AIC drivers"

* tag 'irq-urgent-2021-12-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/irq-bcm7120-l2: Add put_device() after of_find_device_by_node()
  irqchip/irq-gic-v3-its.c: Force synchronisation when issuing INVALL
  irqchip/apple-aic: Mark aic_init_smp() as __init
  irqchip: nvic: Fix offset for Interrupt Priority Offsets
  irqchip/mips-gic: Use bitfield helpers
  irqchip/aspeed-scu: Replace update_bits with write_bits.
  irqchip/armada-370-xp: Fix support for Multi-MSI interrupts
  irqchip/armada-370-xp: Fix return value of armada_370_xp_msi_alloc()

Pull scheduler fix from Thomas Gleixner:
 "A single fix for the x86 scheduler topology:

  Using cluster topology on hybrid CPUs, e.g. Alder Lake, biases the
  scheduler towards the ATOM cluster as that has more total capacity.
  Use selection based on CPU priority instead"

* tag 'sched-urgent-2021-12-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched,x86: Don't use cluster topology for x86 hybrid CPUs

Pull csky from Guo Ren:
 "Only one fix for csky: fix fpu config macro"

* tag 'csky-for-linus-5.16-rc5' of git://github.com/c-sky/csky-linux:
  csky: fix typo of fpu config macro

Using standard USB_EP_MAXP_MULT_MASK instead of individual bits for
extracting multiple-transactions bits from wMaxPacketSize value.
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com>
Link: https://lore.kernel.org/r/20211210085219.16796-2-pavel.hofman@ivitera.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The checks performed by commit aed9d65a ("USB: validate
wMaxPacketValue entries in endpoint descriptors") require that initial
value of the maxp variable contains both maximum packet size bits
(10..0) and multiple-transactions bits (12..11). However, the existing
code assings only the maximum packet size bits. This patch assigns all
bits of wMaxPacketSize to the variable.

Fixes: aed9d65a ("USB: validate wMaxPacketValue entries in endpoint descriptors")
Cc: stable <stable@vger.kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com>
Link: https://lore.kernel.org/r/20211210085219.16796-1-pavel.hofman@ivitera.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Under some conditions, USB gadget devices can show allocated buffer
contents to a host.  Fix this up by zero-allocating them so that any
extra data will all just be zeros.
Reported-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Tested-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Sometimes USB hosts can ask for buffers that are too large from endpoint
0, which should not be allowed.  If this happens for OUT requests, stall
the endpoint, but for IN requests, trim the request size to the endpoint
buffer size.
Co-developed-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull SCSI fixes from James Bottomley:
 "Four fixes, all in drivers.

  Three are small and obvious, the qedi one is a bit larger but also
  pretty obvious"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: qla2xxx: Format log strings only if needed
  scsi: scsi_debug: Fix buffer size of REPORT ZONES command
  scsi: qedi: Fix cmd_cleanup_cmpl counter mismatch issue
  scsi: pm80xx: Do not call scsi_remove_host() in pm8001_alloc()

Pull xfs fix from Darrick Wong:
 "This fixes a race between a readonly remount process and other
  processes that hold a file IOLOCK on files that previously experienced
  copy on write, that could result in severe filesystem corruption if
  the filesystem is then remounted rw.

  I think this is fairly rare (since the only reliable reproducer I have
  that fits the second criteria is the experimental xfs_scrub program),
  but the race is clear, so we still need to fix this.

  Summary:

   - Fix a data corruption vector that can result from the ro remount
     process failing to clear all speculative preallocations from files
     and the rw remount process not noticing the incomplete cleanup"

* tag 'xfs-5.16-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: remove all COW fork extents when remounting readonly