Git is fairly ubiquitous these days, and the additional information in
this documentation for preparing patches without it is not especially
relevant anymore and may serve to confuse new contributors.

The git request-pull comments were also removed, given that it is not a
tool well-suited to novice contributors, nor do maintainers especially
appreciate receiving unexpected request-pulls from new contributors.
Signed-off-by: Drew DeVault <sir@cmpwn.com>
Link: https://lore.kernel.org/r/20200903160545.83185-5-sir@cmpwn.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

The repeated sign-offs necessary when a subsystem maintainer modifies an
incoming patch has been moved from submitting-patches.rst to
Documentation/maintainer, since the affairs of a subsystem maintainer
are not especially relevant to someone reading a guide for how to submit
their first patch.
Signed-off-by: Drew DeVault <sir@cmpwn.com>
Link: https://lore.kernel.org/r/20200903160545.83185-4-sir@cmpwn.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

This adds a link to https://useplaintext.email to email-clients.rst,
which is a more exhaustive resource on configuring various mail clients
for plain text use. submitting-patches.rst is also updated to direct
readers to email-clients.rst to equip new contributors with the
requisite knowledge to become a good participant on the mailing lists.
Signed-off-by: Drew DeVault <sir@cmpwn.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20200903160545.83185-3-sir@cmpwn.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

This follows similar changes throughout Documentation; these numbers
tend to get outdated and are not especially useful.
Signed-off-by: Drew DeVault <sir@cmpwn.com>
Link: https://lore.kernel.org/r/20200903160545.83185-2-sir@cmpwn.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Update text and examples in the "Cross-referencing from
reStructuredText" section to reflect that no additional syntax is needed
anymore.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Link: https://lore.kernel.org/r/20200903005747.3900333-3-nfraprado@protonmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

In order to cross-reference C types in the documentation, Sphinx
requires the syntax :c:type:`type_name`, or even :c:type:`struct
type_name <type_name>` in order to have the link text different from the
target text.

Extend automarkup to enable automatic cross-reference of C types by
matching any "struct|union|enum|typedef type_name" expression.
This makes the documentation's plain text cleaner and adds
cross-reference to types without any additional effort by the author.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Link: https://lore.kernel.org/r/20200903005747.3900333-2-nfraprado@protonmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

In the past, these email lists where located at lists.redhat.com. This
is not longer the case and they are now at redhat.com/mailman/listinfo
Signed-off-by: Javier Garcia <javier@beren.dev>
Link: https://lore.kernel.org/r/20200901090949.14514-1-javier@beren.devSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Greg has challenged some recent driver submitters on their license
choices. He was correct to do so, as the choices in these instances
did not always advance the aims of the submitters.

But, this left submitters (and the folks who help them pick licenses)
a bit confused. They have read things like
Documentation/process/license-rules.rst which says:

	individual source files can have a different license
	which is required to be compatible with the GPL-2.0

and Documentation/process/submitting-drivers.rst:

	We don't insist on any kind of exclusive GPL licensing,
	and if you wish ... you may well wish to release under
	multiple licenses.

As written, these appear a _bit_ more laissez faire than we've been in
practice lately. It sounds like we at least expect submitters to make
a well-reasoned license choice and to explain their rationale. It does
not appear that we blindly accept anything that is simply
GPLv2-compatible.

Drivers appear to be the most acute source of misunderstanding, so fix
the driver documentation first. Update it to clarify expectations.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: H. Peter Anvin <h.peter.anvin@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200814145625.8B708079@viggo.jf.intel.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

It's now gone from the kernel so remove it from the deprecated API text.
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/5e10c1645dd8f735215cf54a74db0f8dd3f6cbd5.camel@perches.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Based on a vote at the LLVM BoF at Plumbers 2020, we decided to start
small, supporting just one formal upstream release of LLVM for now.

We can probably widen the support window of supported versions over
time.  Also, note that LLVM's release process is different than GCC's.
GCC tends to have 1 major release per year while releasing minor updates
to the past 3 major versions.  LLVM tends to support one major release
and one minor release every six months.
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200826191555.3350406-1-ndesaulniers@google.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

The submitting patches mentions criteria for a fix to be called
"security fix".  Add a link to document explaining the entire process
of handling security bugs.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Felipe Balbi <balbi@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200827105319.9734-1-krzk@kernel.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

While the xensource.com URLs referenced still exist, neither the Xen or Linux
2.6.18 fork have been touched since 2009, 11 years ago.  Other URLs are dead.

IA64 support was removed in Xen 4.2, in 2012.  Relegate this piece of
documentation to source history.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Link: https://lore.kernel.org/r/20200827175405.24344-1-andrew.cooper3@citrix.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Translate this commit to Korean:

    3e79f082 ("libnvdimm/nvdimm/flush: Allow architecture to override the flush barrier")
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Yunjae Lee <lyj7694@gmail.com>
Link: https://lore.kernel.org/r/20200829084027.4591-1-sj38.park@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Translate this commit to Korean:

    a897b13d ("docs/memory-barriers.txt: Remove remaining references to mmiowb()")
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Yunjae Lee <lyj7694@gmail.com>
Link: https://lore.kernel.org/r/20200829082607.3146-3-sj38.park@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Commit 985098a0 ("docs: fix references for DMA*.txt files") missed
fixing memory-barriers.txt file.  This commit applies the change to the
file.
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Link: https://lore.kernel.org/r/20200829082607.3146-2-sj38.park@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

The sentence regarding version numbers of '-stable' kernels is quite
ambiguous.  This commit makes the sentence more clear and fix
inconsistent uses of the terms for 'version'.
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Link: https://lore.kernel.org/r/20200829082343.2979-3-sj38.park@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Translate this commit to Korean:

    fb0e0ffe ("Documentation: bring process docs up to date")
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Link: https://lore.kernel.org/r/20200829082343.2979-2-sj38.park@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Fix underline length build warning in thinkpad-acpi.rst documentation:

Documentation/admin-guide/laptops/thinkpad-acpi.rst:1437: WARNING: Title underline too short.
DYTC Lapmode sensor
------------------

Fixes: acf7f4a5 ("platform/x86: thinkpad_acpi: lap or desk mode interface")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/7b2ecef9-dfb7-808a-7c05-4e4f44b363c4@infradead.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Typo fix for abituguru,abituguru3 and abituguru-datasheet
Signed-off-by: Brandon Jiang <brandon.jiang.a@outlook.com>
Link: https://lore.kernel.org/r/DM5PR22MB0892E4FEFCA9ED055B0A8E71AC580@DM5PR22MB0892.namprd22.prod.outlook.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

I noticed a double-() in the deprecated.rst rendering today. Fix that
one and two others in the Documentation/ tree.

Acked-by: "Paul E. McKenney" <paulmck@kernel.org> # For RCU
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200817233207.4083538-1-keescook@chromium.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Signed-off-by: Theodore Dubois <tblodt@icloud.com>
Link: https://lore.kernel.org/r/20200816233823.86316-1-tblodt@icloud.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

As long as there are only a few maintainer entry profiles, i.e., three
in v5.8, continue to maintain a complete a list of entries in the
maintainer handbook.

Complete the list by adding the RISC-V ARCHITECTURE maintainer entry
profile found in MAINTAINERS.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20200815115728.15128-1-lukas.bulwahn@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Since commit 53b7f3aa ("Add a maintainer entry profile for
documentation"), the documentation "subsystem" has a maintainer entry
profile, and it deserves to be mentioned in MAINTAINERS with a suitable
P: entry.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200815102658.12236-1-lukas.bulwahn@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Replace :c:func: with func() as the previous usage is deprecated.
Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Link: https://lore.kernel.org/r/20200812180224.24810-1-puranjay12@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Replace :c:func: with func() as the previous usage is deprecated.
Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Link: https://lore.kernel.org/r/20200812174611.18580-1-puranjay12@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Fix issues with local_locks documentation:
- fix function names, local_lock.h has local_unlock_irqrestore(),
not local_lock_irqrestore()
- fix mapping table, local_unlock_irqrestore() maps to local_irq_restore(),
not _save()
Signed-off-by: Marta Rybczynska <rybczynska@gmail.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/CAApg2=SKxQ3Sqwj6TZnV-0x0cKLXFKDaPvXT4N15MPDMKq724g@mail.gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Pull io_uring fixes from Jens Axboe:
 "A few differerent things in here.

  Seems like syzbot got some more io_uring bits wired up, and we got a
  handful of reports and the associated fixes are in here.

  General fixes too, and a lot of them marked for stable.

  Lastly, a bit of fallout from the async buffered reads, where we now
  more easily trigger short reads. Some applications don't really like
  that, so the io_read() code now handles short reads internally, and
  got a cleanup along the way so that it's now easier to read (and
  documented). We're now passing tests that failed before"

* tag 'io_uring-5.9-2020-08-15' of git://git.kernel.dk/linux-block:
  io_uring: short circuit -EAGAIN for blocking read attempt
  io_uring: sanitize double poll handling
  io_uring: internally retry short reads
  io_uring: retain iov_iter state over io_read/io_write calls
  task_work: only grab task signal lock when needed
  io_uring: enable lookup of links holding inflight files
  io_uring: fail poll arm on queue proc failure
  io_uring: hold 'ctx' reference around task_work queue + execute
  fs: RWF_NOWAIT should imply IOCB_NOIO
  io_uring: defer file table grabbing request cleanup for locked requests
  io_uring: add missing REQ_F_COMP_LOCKED for nested requests
  io_uring: fix recursive completion locking on oveflow flush
  io_uring: use TWA_SIGNAL for task_work uncondtionally
  io_uring: account locked memory before potential error case
  io_uring: set ctx sq/cq entry count earlier
  io_uring: Fix NULL pointer dereference in loop_rw_iter()
  io_uring: add comments on how the async buffered read retry works
  io_uring: io_async_buf_func() need not test page bit

Commit 1355c31e ("asm-generic: pgalloc: provide generic pmd_alloc_one()
and pmd_free_one()") converted parisc to use generic version of
pmd_alloc_one() but it missed the fact that parisc uses order-1 pages for
PMD.

Restore the original version of pmd_alloc_one() for parisc, just use
GFP_PGTABLE_KERNEL that implies __GFP_ZERO instead of GFP_KERNEL and
memset.

Fixes: 1355c31e ("asm-generic: pgalloc: provide generic pmd_alloc_one() and pmd_free_one()")
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Meelis Roos <mroos@linux.ee>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lkml.kernel.org/r/9f2b5ebd-e4a4-0fa1-6cd3-4b9f6892d1ad@linux.eeSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull block fixes from Jens Axboe:
 "A few fixes on the block side of things:

   - Discard granularity fix (Coly)

   - rnbd cleanups (Guoqing)

   - md error handling fix (Dan)

   - md sysfs fix (Junxiao)

   - Fix flush request accounting, which caused an IO slowdown for some
     configurations (Ming)

   - Properly propagate loop flag for partition scanning (Lennart)"

* tag 'block-5.9-2020-08-14' of git://git.kernel.dk/linux-block:
  block: fix double account of flush request's driver tag
  loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE
  rnbd: no need to set bi_end_io in rnbd_bio_map_kern
  rnbd: remove rnbd_dev_submit_io
  md-cluster: Fix potential error pointer dereference in resize_bitmaps()
  block: check queue's limits.discard_granularity in __blkdev_issue_discard()
  md: get sysfs entry after redundancy attr group create

Pull RISC-V fix from Palmer Dabbelt:
 "I collected a single fix during the merge window: we managed to break
  the early trap setup on !MMU, this fixes it"

* tag 'riscv-for-linus-5.9-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: Setup exception vector for nommu platform

Pull arch/sh updates from Rich Felker:
 "Cleanup, SECCOMP_FILTER support, message printing fixes, and other
  changes to arch/sh"

* tag 'sh-for-5.9' of git://git.libc.org/linux-sh: (34 commits)
  sh: landisk: Add missing initialization of sh_io_port_base
  sh: bring syscall_set_return_value in line with other architectures
  sh: Add SECCOMP_FILTER
  sh: Rearrange blocks in entry-common.S
  sh: switch to copy_thread_tls()
  sh: use the generic dma coherent remap allocator
  sh: don't allow non-coherent DMA for NOMMU
  dma-mapping: consolidate the NO_DMA definition in kernel/dma/Kconfig
  sh: unexport register_trapped_io and match_trapped_io_handler
  sh: don't include <asm/io_trapped.h> in <asm/io.h>
  sh: move the ioremap implementation out of line
  sh: move ioremap_fixed details out of <asm/io.h>
  sh: remove __KERNEL__ ifdefs from non-UAPI headers
  sh: sort the selects for SUPERH alphabetically
  sh: remove -Werror from Makefiles
  sh: Replace HTTP links with HTTPS ones
  arch/sh/configs: remove obsolete CONFIG_SOC_CAMERA*
  sh: stacktrace: Remove stacktrace_ops.stack()
  sh: machvec: Modernize printing of kernel messages
  sh: pci: Modernize printing of kernel messages
  ...

One case was missed in the short IO retry handling, and that's hitting
-EAGAIN on a blocking attempt read (eg from io-wq context). This is a
problem on sockets that are marked as non-blocking when created, they
don't carry any REQ_F_NOWAIT information to help us terminate them
instead of perpetually retrying.

Fixes: 227c0c96 ("io_uring: internally retry short reads")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

There's a bit of confusion on the matching pairs of poll vs double poll,
depending on if the request is a pure poll (IORING_OP_POLL_ADD) or
poll driven retry.

Add io_poll_get_double() that returns the double poll waitqueue, if any,
and io_poll_get_single() that returns the original poll waitqueue. With
that, remove the argument to io_poll_remove_double().

Finally ensure that wait->private is cleared once the double poll handler
has run, so that remove knows it's already been seen.

Cc: stable@vger.kernel.org # v5.8
Reported-by: syzbot+7f617d4a9369028b8a2c@syzkaller.appspotmail.com
Fixes: 18bceab1 ("io_uring: allow POLL_ADD with double poll_wait() users")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull more perf tools updates from Arnaldo Carvalho de Melo:
 "Fixes:
   - Fixes for 'perf bench numa'.

   - Always memset source before memcpy in 'perf bench mem'.

   - Quote CC and CXX for their arguments to fix build in environments
     using those variables to pass more than just the compiler names.

   - Fix module symbol processing, addressing regression detected via
     "perf test".

   - Allow multiple probes in record+script_probe_vfs_getname.sh 'perf
     test' entry.

  Improvements:
   - Add script to autogenerate socket family name id->string table from
     copy of kernel header, used so far in 'perf trace'.

   - 'perf ftrace' improvements to provide similar options for this
     utility so that one can go from 'perf record', 'perf trace', etc to
     'perf ftrace' just by changing the name of the subcommand.

   - Prefer new "sched:sched_waking" trace event when it exists in 'perf
     sched' post processing.

   - Update POWER9 metrics to utilize other metrics.

   - Fall back to querying debuginfod if debuginfo not found locally.

  Miscellaneous:
   - Sync various kvm headers with kernel sources"

* tag 'perf-tools-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (40 commits)
  perf ftrace: Make option description initials all capital letters
  perf build-ids: Fall back to debuginfod query if debuginfo not found
  perf bench numa: Remove dead code in parse_nodes_opt()
  perf stat: Update POWER9 metrics to utilize other metrics
  perf ftrace: Add change log
  perf: ftrace: Add set_tracing_options() to set all trace options
  perf ftrace: Add option --tid to filter by thread id
  perf ftrace: Add option -D/--delay to delay tracing
  perf: ftrace: Allow set graph depth by '--graph-opts'
  perf ftrace: Add support for trace option tracing_thresh
  perf ftrace: Add option 'verbose' to show more info for graph tracer
  perf ftrace: Add support for tracing option 'irq-info'
  perf ftrace: Add support for trace option funcgraph-irqs
  perf ftrace: Add support for trace option sleep-time
  perf ftrace: Add support for tracing option 'func_stack_trace'
  perf tools: Add general function to parse sublevel options
  perf ftrace: Add option '--inherit' to trace children processes
  perf ftrace: Show trace column header
  perf ftrace: Add option '-m/--buffer-size' to set per-cpu buffer size
  perf ftrace: Factor out function write_tracing_file_int()
  ...

Pull x86 fixes from Ingo Molnar:
 "Misc fixes and small updates all around the place:

   - Fix mitigation state sysfs output

   - Fix an FPU xstate/sxave code assumption bug triggered by
     Architectural LBR support

   - Fix Lightning Mountain SoC TSC frequency enumeration bug

   - Fix kexec debug output

   - Fix kexec memory range assumption bug

   - Fix a boundary condition in the crash kernel code

   - Optimize porgatory.ro generation a bit

   - Enable ACRN guests to use X2APIC mode

   - Reduce a __text_poke() IRQs-off critical section for the benefit of
     PREEMPT_RT"

* tag 'x86-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/alternatives: Acquire pte lock with interrupts enabled
  x86/bugs/multihit: Fix mitigation reporting when VMX is not in use
  x86/fpu/xstate: Fix an xstate size check warning with architectural LBRs
  x86/purgatory: Don't generate debug info for purgatory.ro
  x86/tsr: Fix tsc frequency enumeration bug on Lightning Mountain SoC
  kexec_file: Correctly output debugging information for the PT_LOAD ELF header
  kexec: Improve & fix crash_exclude_mem_range() to handle overlapping ranges
  x86/crash: Correct the address boundary of function parameters
  x86/acrn: Remove redundant chars from ACRN signature
  x86/acrn: Allow ACRN guest to use X2APIC mode

Pull scheduler fixes from Ingo Molnar:
 "Two fixes: fix a new tracepoint's output value, and fix the formatting
  of show-state syslog printouts"

* tag 'sched-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/debug: Fix the alignment of the show-state debug output
  sched: Fix use of count for nr_running tracepoint

Pull perf fixes from Ingo Molnar:
 "Misc fixes, an expansion of perf syscall access to CAP_PERFMON
  privileged tools, plus a RAPL HW-enablement for Intel SPR platforms"

* tag 'perf-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/rapl: Add support for Intel SPR platform
  perf/x86/rapl: Support multiple RAPL unit quirks
  perf/x86/rapl: Fix missing psys sysfs attributes
  hw_breakpoint: Remove unused __register_perf_hw_breakpoint() declaration
  kprobes: Remove show_registers() function prototype
  perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability

Pull locking fixlets from Ingo Molnar:
 "A documentation fix and a 'fallthrough' macro update"

* tag 'locking-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Convert to use the preferred 'fallthrough' macro
  Documentation/locking/locktypes: Fix a typo

Pull 9p updates from Dominique Martinet:

 - some code cleanup

 - a couple of static analysis fixes

 - setattr: try to pick a fid associated with the file rather than the
   dentry, which might sometimes matter

* tag '9p-for-5.9-rc1' of git://github.com/martinetd/linux:
  9p: Remove unneeded cast from memory allocation
  9p: remove unused code in 9p
  net/9p: Fix sparse endian warning in trans_fd.c
  9p: Fix memory leak in v9fs_mount
  9p: retrieve fid from file when file instance exist.