A "permanent" struct xdr_stream is allocated in struct svc_rqst so
that it is usable by all server-side decoders. A per-rqst scratch
buffer is also allocated to handle decoding XDR data items that
cross page boundaries.

To demonstrate how it will be used, add the first call site for the
new svcxdr_init_decode() API.

As an additional part of the overall conversion, add symbolic
constants for successful and failed XDR operations. Returning "0" is
overloaded. Sometimes it means something failed, but sometimes it
means success. To make it more clear when XDR decoding functions
succeed or fail, introduce symbolic constants.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up: De-duplicate some frequently-used code.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Fix to return PTR_ERR() error code from the error handling case instead of
0 in function nfsd_file_cache_init(), as done elsewhere in this function.

Fixes: 65294c1f("nfsd: add a new struct file caching facility to nfsd")
Signed-off-by: Huang Guobin <huangguobin4@huawei.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up.

The file was contributed in 2014 by Christoph Hellwig in commit
31ef83dc ("nfsd: add trace events").
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up: %p adds its own 0x already.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Display all currently possible NFSD_MAY permission flags.

Move and rename show_nf_may with a more generic name because the
NFSD_MAY permission flags are used in other places besides the file
cache.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Commit c509f15a ("SUNRPC: Split the xdr_buf event class") added
display of the rqst's XID to the svc_xdr_buf_class. However, when
the recvfrom tracepoint fires, rq_xid has yet to be filled in with
the current XID. So it ends up recording the previous XID that was
handled by that svc_rqst.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

The macro is unused, remove it to tame gcc warning:
fs/nfsd/nfs3proc.c:702:0: warning: macro "nfsd3_fhandleres" is not used
[-Wunused-macros]
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: linux-nfs@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

An efficient way to handle multiple Read chunks is to post them all
together and then take a single completion. This is also how the
code is already structured: when the Read completion fires, all
portions of the incoming RPC message are available to be assembled.

The difficult problem is setting up the Read sink buffers so that
the server pulls the client's data into place, making subsequent
pull-up unnecessary. There are several cases:

* No Read chunks. No-op.

* One data item Read chunk. This is the fast case, where the inline
  part of the RPC-over-RDMA message becomes the head and tail, and
  the data item chunk is placed in buf->pages.

* A Position-zero Read chunk. Treated like TCP: the Read chunk is
  pulled into contiguous pages.

+ A Position-zero Read chunk with data item chunks. Treated like
  TCP: all of the Read chunks are pulled into contiguous pages.

+ Multiple data item chunks. Treated like TCP: the inline part is
  copied and the data item chunks are pulled into contiguous pages.

The "*" cases are already supported. This patch adds support for the
"+" cases.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

As a pre-requisite for handling multiple Read chunks in each Read
list, convert svc_rdma_recv_read_chunk() to use the new parsed Read
chunk list.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

I'm about to change the purpose of ri_chunklen: Instead of tracking
the number of bytes in one Read chunk, it will track the total
number of bytes in the Read list. Rename it for clarity.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

We already have trace_svcrdma_decode_rseg(), which records each
ingress Read segment. Instead of reporting those again when they
are about to be posted as RDMA Reads, let's fire one tracepoint
before posting each type of chunk.

So we'll get:

        nfsd-1998  [002]   321.666615: svcrdma_decode_rseg:  cq.id=4 cid=42 segno=0 position=0 192@0x013ca9ebfae14000:0xb0010b05
        nfsd-1998  [002]   321.666615: svcrdma_decode_rseg:  cq.id=4 cid=42 segno=1 position=0 7688@0x013ca9ebf914e000:0xb0010a05
        nfsd-1998  [002]   321.666615: svcrdma_decode_rseg:  cq.id=4 cid=42 segno=2 position=0 28@0x013ca9ebfae15000:0xb0010905
        nfsd-1998  [002]   321.666622: svcrdma_decode_rqst:  cq.id=4 cid=42 xid=0x013ca9eb vers=1 credits=128 proc=RDMA_NOMSG hdrlen=100

        nfsd-1998  [002]   321.666642: svcrdma_post_read_chunk: cq.id=3 cid=112 sqecount=3

kworker/2:1H-221   [002]   321.673949: svcrdma_wc_read:      cq.id=3 cid=112 status=SUCCESS (0/0x0)
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up: These pointers are no longer used.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Refactor svc_rdma_send_reply_chunk() so that it Sends only the parts
of rq_res that do not contain a result payload.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Refactor: svc_rdma_map_reply_msg() is restructured to DMA map only
the parts of rq_res that do not contain a result payload.

This change has been tested to confirm that it does not cause a
regression in the no Write chunk and single Write chunk cases.
Multiple Write chunks have not been tested.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

When counting the number of SGEs needed to construct a Send request,
do not count result payloads. And, when copying the Reply message
into the pull-up buffer, result payloads are not to be copied to the
Send buffer.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Refactor: Instead of re-parsing the ingress RPC Call transport
header when constructing the egress RPC Reply transport header, use
the new parsed Write list and Reply chunk, which are version-
agnostic and already XDR decoded.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Refactor: Instead of re-parsing the ingress RPC Call transport
header when constructing RDMA Writes, use the new parsed chunk lists
for the Write list and Reply chunk, which are version-agnostic and
already XDR-decoded.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Refactor: Don't duplicate header decoding smarts here. Instead, use
the new parsed chunk lists.

Note that the XID sanity test is also removed. The XID is already
looked up by the cb handler, and is rejected if it's not recognized.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Refactor: Don't duplicate header decoding smarts here. Instead, use
the new parsed chunk lists.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

This simple data structure binds the location of each data payload
inside of an RPC message to the chunk that will be used to push it
to or pull it from the client.

There are several benefits to this small additional overhead:

 * It enables support for more than one chunk in incoming Read and
   Write lists.

 * It translates the version-specific on-the-wire format into a
   generic in-memory structure, enabling support for multiple
   versions of the RPC/RDMA transport protocol.

 * It enables the server to re-organize a chunk list if it needs to
   adjust where Read chunk data lands in server memory without
   altering the contents of the XDR-encoded Receive buffer.

Construction of these lists is done while sanity checking each
incoming RPC/RDMA header. Subsequent patches will make use of the
generated data structures.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Refactor: Match the control flow of svc_rdma_encode_write_list().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

The only RPC/RDMA ordering requirement between RDMA Writes and RDMA
Sends is that the responder must post the Writes on the Send queue
before posting the Send that conveys the RPC Reply for that Write
payload.

The Linux NFS server implementation now has a transport method that
can post result Payload Writes earlier than svc_rdma_sendto:

   ->xpo_result_payload()

This gets RDMA Writes going earlier so they are more likely to be
complete at the remote end before the Send completes.

Some care must be taken with pulled-up Replies. We don't want to
push the Write chunk and then send the same payload data via Send.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Have the NFSD encoders annotate the boundaries of every
direct-data-placement eligible result data payload. Then change
svcrdma to use that annotation instead of the xdr->page_len
when handling Write chunks.

For NFSv4 on RDMA, that enables the ability to recognize multiple
result payloads per compound. This is a pre-requisite for supporting
multiple Write chunks per RPC transaction.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up: "result payload" is a less confusing name for these
payloads. "READ payload" reflects only the NFS usage.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Refactor for subsequent changes.

Constify the xdr_buf argument to ensure the code here does not
modify it, and to enable callers to pass in a
"const struct xdr_buf *".

At the same time, rename the helper functions, which emit RDMA
Writes, not RDMA Sends, and add documenting comments.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up: Ensure the code in rw.c does not modify the argument, and
enable callers to also use "const struct xdr_buf *".
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Clean up: This enables xdr_buf_subsegment()'s callers to pass in a
const pointer to that buffer.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

When space in the Reply chunk runs out in the middle of a segment,
we end up passing a zero-length SGL to rdma_rw_ctx_init(), and it
oopses.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Pull locking fixes from Thomas Gleixner:
 "Two more places which invoke tracing from RCU disabled regions in the
  idle path.

  Similar to the entry path the low level idle functions have to be
  non-instrumentable"

* tag 'locking-urgent-2020-11-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  intel_idle: Fix intel_idle() vs tracing
  sched/idle: Fix arch_cpu_idle() vs tracing

Pull irq fixes from Thomas Gleixner:
 "Two fixes for irqchip drivers:

   - Save and restore the GICV3 ITS state unconditionally on
     suspend/resume to handle firmware which fails to do so.

   - Use the correct index into the fwspec parameters to read the irq
     trigger type in the EXIU chip driver"

* tag 'irq-urgent-2020-11-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3-its: Unconditionally save/restore the ITS state on suspend
  irqchip/exiu: Fix the index of fwspec for IRQ type

Pull EFI fixes from Borislav Petkov:
 "More EFI fixes forwarded from Ard Biesheuvel:

   - revert efivarfs kmemleak fix again - it was a false positive

   - make CONFIG_EFI_EARLYCON depend on CONFIG_EFI explicitly so it does
     not pull in other dependencies unnecessarily if CONFIG_EFI is not
     set

   - defer attempts to load SSDT overrides from EFI vars until after the
     efivar layer is up"

* tag 'efi-urgent-for-v5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: EFI_EARLYCON should depend on EFI
  efivarfs: revert "fix memory leak in efivarfs_create()"
  efi/efivars: Set generic ops before loading SSDT

Pull x86 fixes from Borislav Petkov:
 "A couple of urgent fixes which accumulated this last week:

   - Two resctrl fixes to prevent refcount leaks when manipulating the
     resctrl fs (Xiaochen Shen)

   - Correct prctl(PR_GET_SPECULATION_CTRL) reporting (Anand K Mistry)

   - A fix to not lose already seen MCE severity which determines
     whether the machine can recover (Gabriele Paoloni)"

* tag 'x86_urgent_for_v5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Do not overwrite no_way_out if mce_end() fails
  x86/speculation: Fix prctl() when spectre_v2_user={seccomp,prctl},ibpb
  x86/resctrl: Add necessary kernfs_put() calls to prevent refcount leak
  x86/resctrl: Remove superfluous kernfs_get() calls to prevent refcount leak

Pull RISC-V fixes from Palmer Dabbelt:
 "I've collected a handful of fixes over the past few weeks:

   - A fix to un-break the build-id argument to the vDSO build, which is
     necessary for the LLVM linker.

   - A fix to initialize the jump label subsystem, without which it (and
     all the stuff that uses it) doesn't actually function.

   - A fix to include <asm/barrier.h> from <vdso/processor.h>, without
     which some drivers won't compile"

* tag 'riscv-for-linus-5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: fix barrier() use in <vdso/processor.h>
  RISC-V: Add missing jump label initialization
  riscv: Explicitly specify the build id style in vDSO Makefile again

Merge tag 'kbuild-fixes-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Remove unused OBJSIZE variable.

 - Fix rootless deb-pkg build in a setgid directory.

* tag 'kbuild-fixes-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  builddeb: Fix rootless build in setuid/setgid directory
  kbuild: remove unused OBJSIZE

Merge tag 'perf-tools-fixes-for-v5.10-2020-11-28' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

Pull perf tool fixes from Arnaldo Carvalho de Melo:

 - Fix die_entrypc() when DW_AT_ranges DWARF attribute not available

 - Cope with broken DWARF (missing DW_AT_declaration) generated by some
   recent gcc versions

 - Do not generate CGROUP metadata events when not asked to in 'perf
   record'

 - Use proper CPU for shadow stats in 'perf stat'

 - Update copy of libbpf's hashmap.c, silencing tools/perf build warning

 - Fix return value in 'perf diff'

* tag 'perf-tools-fixes-for-v5.10-2020-11-28' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
  perf probe: Change function definition check due to broken DWARF
  perf probe: Fix to die_entrypc() returns error correctly
  perf stat: Use proper cpu for shadow stats
  perf record: Synthesize cgroup events only if needed
  perf diff: Fix error return value in __cmd_diff()
  perf tools: Update copy of libbpf's hashmap.c

Pull USB / PHY driver fixes from Greg KH:
 "Here are a few small USB and PHY driver fixes for 5.10-rc6. They
  include:

   - small PHY driver fixes to resolve reported issues

   - USB quirks added for "broken" devices

   - typec fixes for reported problems

   - USB gadget fixes for small issues

  Full details are in the shortlog, nothing major in here and all have
  been in linux-next with no reported issues"

* tag 'usb-5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: typec: stusb160x: fix power-opmode property with typec-power-opmode
  USB: core: Change %pK for __user pointers to %px
  USB: core: Fix regression in Hercules audio card
  usb: gadget: Fix memleak in gadgetfs_fill_super
  usb: gadget: f_midi: Fix memleak in f_midi_alloc
  USB: quirks: Add USB_QUIRK_DISCONNECT_SUSPEND quirk for Lenovo A630Z TIO built-in usb-audio card
  usb: typec: qcom-pmic-typec: fix builtin build errors
  phy: mediatek: fix spelling mistake in Kconfig "veriosn" -> "version"
  phy: qualcomm: Fix 28 nm Hi-Speed USB PHY OF dependency
  phy: qualcomm: usb: Fix SuperSpeed PHY OF dependency
  phy: intel: PHY_INTEL_KEEMBAY_EMMC should depend on ARCH_KEEMBAY
  usb: cdns3: gadget: calculate TD_SIZE based on TD
  usb: cdns3: gadget: initialize link_trb as NULL
  phy: cpcap-usb: Use IRQF_ONESHOT
  phy: qcom-qmp: Initialize another pointer to NULL
  phy: tegra: xusb: Fix dangling pointer on probe failure
  phy: usb: Fix incorrect clearing of tca_drv_sel bit in SETUP reg for 7211

Pull char/misc driver fixes from Greg KH:
 "Here are some small misc driver fixes for 5.10-rc6.  They include:

   - interconnect fixes for reported problems

   - habanalabs bugfix for found issue when doing the switch fallthrough
     patches

   - MAINTAINERS file update for coresight reviewers/maintainers

  All have been in linux-next with no reported issues"

* tag 'char-misc-5.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  MAINTAINERS: Adding help for coresight subsystem
  habanalabs/gaudi: fix missing code in ECC handling
  interconnect: fix memory trashing in of_count_icc_providers()
  interconnect: qcom: qcs404: Remove GPU and display RPM IDs
  interconnect: qcom: msm8916: Remove rpm-ids from non-RPM nodes
  interconnect: qcom: msm8974: Don't boost the NoC rate during boot
  interconnect: qcom: msm8974: Prevent integer overflow in rate