p9_tag_alloc() is supposed to return error pointers, but we accidentally
return a NULL here.  It would cause a NULL dereference in the caller.

Link: http://lkml.kernel.org/m/20180926103934.GA14535@mwanda
Fixes: 996d5b4d ("9p: Use a slab for allocating requests")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

the 9p client code overwrites our glock.client_id pointing to a static
buffer by an allocated string holding the network provided value which
we do not care about; free and reset the value as appropriate.

This is almost identical to the leak in v9fs_file_getlock() fixed by
Al Viro in commit ce85dd58 ("9p: we are leaking glock.client_id
in v9fs_file_getlock()"), which was returned as an error by a coverity
false positive -- while we are here attempt to make the code slightly
more robust to future change of the net/9p/client code and hopefully
more clear to coverity that there is no problem.

Link: http://lkml.kernel.org/r/1536339057-21974-5-git-send-email-asmadeus@codewreck.orgSigned-off-by: Dominique Martinet <dominique.martinet@cea.fr>

strcpy to dirent->d_name could overflow the buffer, use strscpy to check
the provided string length and error out if the size was too big.

While we are here, make the function return an error when the pdu
parsing failed, instead of returning the pdu offset as if it had been a
success...

Link: http://lkml.kernel.org/r/1536339057-21974-4-git-send-email-asmadeus@codewreck.org
Addresses-Coverity-ID: 139133 ("Copy into fixed size buffer")
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

the client c is always dereferenced to get the rdma struct, so c has to
be a valid pointer at this point.
Gcc would optimize that away but let's make coverity happy...

Link: http://lkml.kernel.org/r/1536339057-21974-3-git-send-email-asmadeus@codewreck.org
Addresses-Coverity-ID: 102778 ("Dereference before null check")
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

iattr is passed to v9fs_vfs_setattr_dotl which does send various
values from iattr over the wire, even if it tells the server to
only look at iattr.ia_valid fields this could leak some stack data.

Link: http://lkml.kernel.org/r/1536339057-21974-2-git-send-email-asmadeus@codewreck.org
Addresses-Coverity-ID: 1195601 ("Uninitalized scalar variable")
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

The default P9_LOCK_TIMEOUT can be too long for some users exporting
a local file system to a guest VM (30s), make this configurable at
mount time.

Link: http://lkml.kernel.org/r/1536295827-3181-1-git-send-email-asmadeus@codewreck.org
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=195727Signed-off-by: Dinu-Razvan Chis-Serban <justcsdr@gmail.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

v9fs_dir_readdir() could deadloop if a struct was sent with a size set
to -2

Link: http://lkml.kernel.org/r/1536134432-11997-1-git-send-email-asmadeus@codewreck.org
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=88021Signed-off-by: Gertjan Halkes <gertjan@google.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

In struct p9_conn, rename req to rreq as it is used by the read routine.

Link: http://lkml.kernel.org/r/20180903160321.2181-1-tomasbortoli@gmail.comSigned-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Suggested-by: Jun Piao <piaojun@huawei.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

Replace "fallthough" with a proper "fall through" annotation.

This fix is part of the ongoing efforts to enabling -Wimplicit-fallthrough

Link: http://lkml.kernel.org/r/20180903193806.GA11258@embeddedor.com
Addresses-Coverity-ID: 402012 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

9p/rdma would sometimes drop the connection and display errors in
recv_done when the user does ^C.
The errors were caused by recv buffers that were posted at the time
of disconnect, and we just do not want to disconnect when
down_interruptible is... interrupted.

Link: http://lkml.kernel.org/r/1535625307-18019-1-git-send-email-asmadeus@codewreck.orgSigned-off-by: Dominique Martinet <dominique.martinet@cea.fr>

To avoid use-after-free(s), use a refcount to keep track of the
usable references to any instantiated struct p9_req_t.

This commit adds p9_req_put(), p9_req_get() and p9_req_try_get() as
wrappers to kref_put(), kref_get() and kref_get_unless_zero().
These are used by the client and the transports to keep track of
valid requests' references.

p9_free_req() is added back and used as callback by kref_put().

Add SLAB_TYPESAFE_BY_RCU as it ensures that the memory freed by
kmem_cache_free() will not be reused for another type until the rcu
synchronisation period is over, so an address gotten under rcu read
lock is safe to inc_ref() without corrupting random memory while
the lock is held.

Link: http://lkml.kernel.org/r/1535626341-20693-1-git-send-email-asmadeus@codewreck.orgCo-developed-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Reported-by: syzbot+467050c1ce275af2a5b8@syzkaller.appspotmail.com
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

In sight of the next patch to add a refcount in p9_req_t, rename
the p9_free_req() function in p9_release_req().

In the next patch the actual kfree will be moved to another function.

Link: http://lkml.kernel.org/r/20180811144254.23665-1-tomasbortoli@gmail.comSigned-off-by: Tomas Bortoli <tomasbortoli@gmail.com>
Acked-by: Jun Piao <piaojun@huawei.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

Having a specific cache for the fcall allocations helps speed up
end-to-end latency.

The caches will automatically be merged if there are multiple caches
of items with the same size so we do not need to try to share a cache
between different clients of the same size.

Since the msize is negotiated with the server, only allocate the cache
after that negotiation has happened - previous allocations or
allocations of different sizes (e.g. zero-copy fcall) are made with
kmalloc directly.

Some figures on two beefy VMs with Connect-IB (sriov) / trans=rdma,
with ior running 32 processes in parallel doing small 32 bytes IOs:
 - no alloc (4.18-rc7 request cache): 65.4k req/s
 - non-power of two alloc, no patch: 61.6k req/s
 - power of two alloc, no patch: 62.2k req/s
 - non-power of two alloc, with patch: 64.7k req/s
 - power of two alloc, with patch: 65.1k req/s

Link: http://lkml.kernel.org/r/1532943263-24378-2-git-send-email-asmadeus@codewreck.orgSigned-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Greg Kurz <groug@kaod.org>

'msize' is often a power of two, or at least page-aligned, so avoiding
an overhead of two dozen bytes for each allocation will help the
allocator do its work and reduce memory fragmentation.

Link: http://lkml.kernel.org/r/1533825236-22896-1-git-send-email-asmadeus@codewreck.orgSuggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Reviewed-by: Greg Kurz <groug@kaod.org>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>

There are no more users left of the p9_idpool; delete it.

Link: http://lkml.kernel.org/r/20180711210225.19730-7-willy@infradead.orgSigned-off-by: Matthew Wilcox <willy@infradead.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

Replace the custom batch allocation with a slab.  Use an IDR to store
pointers to the active requests instead of an array.  We don't try to
handle P9_NOTAG specially; the IDR will happily shrink all the way back
once the TVERSION call has completed.

Link: http://lkml.kernel.org/r/20180711210225.19730-6-willy@infradead.orgSigned-off-by: Matthew Wilcox <willy@infradead.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

p9stat_free is more of a cleanup function than a 'free' function as it
only frees the content of the struct; there are chances of use-after-free
if it is improperly used (e.g. p9stat_free called twice as it used to be
possible to)

Clearing dangling pointers makes the function idempotent and safer to use.

Link: http://lkml.kernel.org/r/1535410108-20650-2-git-send-email-asmadeus@codewreck.orgSigned-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Reported-by: syzbot+d4252148d198410b864f@syzkaller.appspotmail.com

p9stat_read will call p9stat_free on error, we should only free the
struct content on success.

There also is no need to "p9stat_init" st as the read function will
zero the whole struct for us anyway, so clean up the code a bit while
we are here.

Link: http://lkml.kernel.org/r/1535410108-20650-1-git-send-email-asmadeus@codewreck.orgSigned-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Reported-by: syzbot+d4252148d198410b864f@syzkaller.appspotmail.com

If the xen bus exists but does not expose the proper interface, it is
possible to get a non-zero length but still some error, leading to
strcmp failing trying to load invalid memory addresses e.g.
fffffffffffffffe.

There is then no need to check length when there is no error, as the
xenbus driver guarantees that the string is nul-terminated.

Link: http://lkml.kernel.org/r/1534236007-10170-1-git-send-email-asmadeus@codewreck.orgSigned-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Latchesar Ionkov <lucho@ionkov.net>

Pull timer update from Thomas Gleixner:
 "New defines for the compat time* types so they can be shared between
  32bit and 64bit builds. Not used yet, but merging them now allows the
  actual conversions to be merged through different maintainer trees
  without dependencies

  We still have compat interfaces for 32bit on 64bit even with the new
  2038 safe timespec/val variants because pointer size is different. And
  for the old style timespec/val interfaces we need yet another 'compat'
  interface for both 32bit native and 32bit on 64bit"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  y2038: Provide aliases for compat helpers

Pull IDA updates from Matthew Wilcox:
 "A better IDA API:

      id = ida_alloc(ida, GFP_xxx);
      ida_free(ida, id);

  rather than the cumbersome ida_simple_get(), ida_simple_remove().

  The new IDA API is similar to ida_simple_get() but better named.  The
  internal restructuring of the IDA code removes the bitmap
  preallocation nonsense.

  I hope the net -200 lines of code is convincing"

* 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax: (29 commits)
  ida: Change ida_get_new_above to return the id
  ida: Remove old API
  test_ida: check_ida_destroy and check_ida_alloc
  test_ida: Convert check_ida_conv to new API
  test_ida: Move ida_check_max
  test_ida: Move ida_check_leaf
  idr-test: Convert ida_check_nomem to new API
  ida: Start new test_ida module
  target/iscsi: Allocate session IDs from an IDA
  iscsi target: fix session creation failure handling
  drm/vmwgfx: Convert to new IDA API
  dmaengine: Convert to new IDA API
  ppc: Convert vas ID allocation to new IDA API
  media: Convert entity ID allocation to new IDA API
  ppc: Convert mmu context allocation to new IDA API
  Convert net_namespace to new IDA API
  cb710: Convert to new IDA API
  rsxx: Convert to new IDA API
  osd: Convert to new IDA API
  sd: Convert to new IDA API
  ...

Pull gcc plugin fix from Kees Cook:
 "Lift gcc test into Kconfig. This is for better behavior when the
  kernel is built with Clang, reported by Stefan Agner"

* tag 'gcc-plugins-v4.19-rc1-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-plugins: Disable when building under Clang

Pull perf updates from Thomas Gleixner:
 "Kernel:
   - Improve kallsyms coverage
   - Add x86 entry trampolines to kcore
   - Fix ARM SPE handling
   - Correct PPC event post processing

  Tools:
   - Make the build system more robust
   - Small fixes and enhancements all over the place
   - Update kernel ABI header copies
   - Preparatory work for converting libtraceevnt to a shared library
   - License cleanups"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (100 commits)
  tools arch: Update arch/x86/lib/memcpy_64.S copy used in 'perf bench mem memcpy'
  tools arch x86: Update tools's copy of cpufeatures.h
  perf python: Fix pyrf_evlist__read_on_cpu() interface
  perf mmap: Store real cpu number in 'struct perf_mmap'
  perf tools: Remove ext from struct kmod_path
  perf tools: Add gzip_is_compressed function
  perf tools: Add lzma_is_compressed function
  perf tools: Add is_compressed callback to compressions array
  perf tools: Move the temp file processing into decompress_kmodule
  perf tools: Use compression id in decompress_kmodule()
  perf tools: Store compression id into struct dso
  perf tools: Add compression id into 'struct kmod_path'
  perf tools: Make is_supported_compression() static
  perf tools: Make decompress_to_file() function static
  perf tools: Get rid of dso__needs_decompress() call in __open_dso()
  perf tools: Get rid of dso__needs_decompress() call in symbol__disassemble()
  perf tools: Get rid of dso__needs_decompress() call in read_object_code()
  tools lib traceevent: Change to SPDX License format
  perf llvm: Allow passing options to llc in addition to clang
  perf parser: Improve error message for PMU address filters
  ...

Pull x86 fixes from Thomas Gleixner:

 - Correct the L1TF fallout on 32bit and the off by one in the 'too much
   RAM for protection' calculation.

 - Add a helpful kernel message for the 'too much RAM' case

 - Unbreak the VDSO in case that the compiler desides to use indirect
   jumps/calls and emits retpolines which cannot be resolved because the
   kernel uses its own thunks, which does not work for the VDSO. Make it
   use the builtin thunks.

 - Re-export start_thread() which was unexported when the 32/64bit
   implementation was unified. start_thread() is required by modular
   binfmt handlers.

 - Trivial cleanups

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation/l1tf: Suggest what to do on systems with too much RAM
  x86/speculation/l1tf: Fix off-by-one error when warning that system has too much RAM
  x86/kvm/vmx: Remove duplicate l1d flush definitions
  x86/speculation/l1tf: Fix overflow in l1tf_pfn_limit() on 32bit
  x86/process: Re-export start_thread()
  x86/mce: Add notifier_block forward declaration
  x86/vdso: Fix vDSO build if a retpoline is emitted

Pull irq update from Thomas Gleixner:
 "A small set of updats/fixes for the irq subsystem:

   - Allow GICv3 interrupts to be configured as wake-up sources to
     enable wakeup from suspend

   - Make the error handling of the STM32 irqchip init function work

   - A set of small cleanups and improvements"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3: Allow interrupt to be configured as wake-up sources
  irqchip/tango: Set irq handler and data in one go
  dt-bindings: irqchip: renesas-irqc: Document r8a774a1 support
  irqchip/s3c24xx: Remove unneeded comparison of unsigned long to 0
  irqchip/stm32: Fix init error handling
  irqchip/bcm7038-l1: Hide cpu offline callback when building for !SMP

Pull licking update from Thomas Gleixner:
 "Mark the switch cases which fall through to the next case with the
  proper comment so the fallthrough compiler checks can be enabled"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Mark expected switch fall-throughs

Merge tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm memory-failure update from Dave Jiang:
 "As it stands, memory_failure() gets thoroughly confused by dev_pagemap
  backed mappings. The recovery code has specific enabling for several
  possible page states and needs new enabling to handle poison in dax
  mappings.

  In order to support reliable reverse mapping of user space addresses:

   1/ Add new locking in the memory_failure() rmap path to prevent races
      that would typically be handled by the page lock.

   2/ Since dev_pagemap pages are hidden from the page allocator and the
      "compound page" accounting machinery, add a mechanism to determine
      the size of the mapping that encompasses a given poisoned pfn.

   3/ Given pmem errors can be repaired, change the speculatively
      accessed poison protection, mce_unmap_kpfn(), to be reversible and
      otherwise allow ongoing access from the kernel.

  A side effect of this enabling is that MADV_HWPOISON becomes usable
  for dax mappings, however the primary motivation is to allow the
  system to survive userspace consumption of hardware-poison via dax.
  Specifically the current behavior is:

     mce: Uncorrected hardware memory error in user-access at af34214200
     {1}[Hardware Error]: It has been corrected by h/w and requires no further action
     mce: [Hardware Error]: Machine check events logged
     {1}[Hardware Error]: event severity: corrected
     Memory failure: 0xaf34214: reserved kernel page still referenced by 1 users
     [..]
     Memory failure: 0xaf34214: recovery action for reserved kernel page: Failed
     mce: Memory error not recovered
     <reboot>

  ...and with these changes:

     Injecting memory failure for pfn 0x20cb00 at process virtual address 0x7f763dd00000
     Memory failure: 0x20cb00: Killing dax-pmd:5421 due to hardware memory corruption
     Memory failure: 0x20cb00: recovery action for dax page: Recovered

  Given all the cross dependencies I propose taking this through
  nvdimm.git with acks from Naoya, x86/core, x86/RAS, and of course dax
  folks"

* tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm, pmem: Restore page attributes when clearing errors
  x86/memory_failure: Introduce {set, clear}_mce_nospec()
  x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses
  mm, memory_failure: Teach memory_failure() about dev_pagemap pages
  filesystem-dax: Introduce dax_lock_mapping_entry()
  mm, memory_failure: Collect mapping size in collect_procs()
  mm, madvise_inject_error: Let memory_failure() optionally take a page reference
  mm, dev_pagemap: Do not clear ->mapping on final put
  mm, madvise_inject_error: Disable MADV_SOFT_OFFLINE for ZONE_DEVICE pages
  filesystem-dax: Set page->index
  device-dax: Set page->index
  device-dax: Enable page_mapping()
  device-dax: Convert to vmf_insert_mixed and vm_fault_t

Pull libnvdimm updates from Dave Jiang:
 "Collection of misc libnvdimm patches for 4.19 submission:

   - Adding support to read locked nvdimm capacity.

   - Change test code to make DSM failure code injection an override.

   - Add support for calculate maximum contiguous area for namespace.

   - Add support for queueing a short ARS when there is on going ARS for
     nvdimm.

   - Allow NULL to be passed in to ->direct_access() for kaddr and pfn
     params.

   - Improve smart injection support for nvdimm emulation testing.

   - Fix test code that supports for emulating controller temperature.

   - Fix hang on error before devm_memremap_pages()

   - Fix a bug that causes user memory corruption when data returned to
     user for ars_status.

   - Maintainer updates for Ross Zwisler emails and adding Jan Kara to
     fsdax"

* tag 'libnvdimm-for-4.19_misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm: fix ars_status output length calculation
  device-dax: avoid hang on error before devm_memremap_pages()
  tools/testing/nvdimm: improve emulation of smart injection
  filesystem-dax: Do not request kaddr and pfn when not required
  md/dm-writecache: Don't request pointer dummy_addr when not required
  dax/super: Do not request a pointer kaddr when not required
  tools/testing/nvdimm: kaddr and pfn can be NULL to ->direct_access()
  s390, dcssblk: kaddr and pfn can be NULL to ->direct_access()
  libnvdimm, pmem: kaddr and pfn can be NULL to ->direct_access()
  acpi/nfit: queue issuing of ars when an uc error notification comes in
  libnvdimm: Export max available extent
  libnvdimm: Use max contiguous area for namespace size
  MAINTAINERS: Add Jan Kara for filesystem DAX
  MAINTAINERS: update Ross Zwisler's email address
  tools/testing/nvdimm: Fix support for emulating controller temperature
  tools/testing/nvdimm: Make DSM failure code injection an override
  acpi, nfit: Prefer _DSM over _LSR for namespace label reads
  libnvdimm: Introduce locked DIMM capacity support

Pull ARM SoC late updates from Olof Johansson:
 "A couple of late-merged changes that would be useful to get in this
  merge window:

   - Driver support for reset of audio complex on Meson platforms. The
     audio driver went in this merge window, and these changes have been
     in -next for a while (just not in our tree).

   - Power management fixes for IOMMU on Rockchip platforms, getting
     closer to kexec working on them, including Chromebooks.

   - Another pass updating "arm,psci" -> "psci" for some properties that
     have snuck in since last time it was done"

* tag 'armsoc-late' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  iommu/rockchip: Move irq request past pm_runtime_enable
  iommu/rockchip: Handle errors returned from PM framework
  arm64: rockchip: Force CONFIG_PM on Rockchip systems
  ARM: rockchip: Force CONFIG_PM on Rockchip systems
  arm64: dts: Fix various entry-method properties to reflect documentation
  reset: imx7: Fix always writing bits as 0
  reset: meson: add meson audio arb driver
  reset: meson: add dt-bindings for meson-axg audio arb

Pull more Kbuild updates from Masahiro Yamada:

 - add build_{menu,n,g,x}config targets for compile-testing Kconfig

 - fix and improve recursive dependency detection in Kconfig

 - fix parallel building of menuconfig/nconfig

 - fix syntax error in clang-version.sh

 - suppress distracting log from syncconfig

 - remove obsolete "rpm" target

 - remove VMLINUX_SYMBOL(_STR) macro entirely

 - fix microblaze build with CONFIG_DYNAMIC_FTRACE

 - move compiler test for dead code/data elimination to Kconfig

 - rename well-known LDFLAGS variable to KBUILD_LDFLAGS

 - misc fixes and cleanups

* tag 'kbuild-v4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: rename LDFLAGS to KBUILD_LDFLAGS
  kbuild: pass LDFLAGS to recordmcount.pl
  kbuild: test dead code/data elimination support in Kconfig
  initramfs: move gen_initramfs_list.sh from scripts/ to usr/
  vmlinux.lds.h: remove stale <linux/export.h> include
  export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR()
  Coccinelle: remove pci_alloc_consistent semantic to detect in zalloc-simple.cocci
  kbuild: make sorting initramfs contents independent of locale
  kbuild: remove "rpm" target, which is alias of "rpm-pkg"
  kbuild: Fix LOADLIBES rename in Documentation/kbuild/makefiles.txt
  kconfig: suppress "configuration written to .config" for syncconfig
  kconfig: fix "Can't open ..." in parallel build
  kbuild: Add a space after `!` to prevent parsing as file pattern
  scripts: modpost: check memory allocation results
  kconfig: improve the recursive dependency report
  kconfig: report recursive dependency involving 'imply'
  kconfig: error out when seeing recursive dependency
  kconfig: add build-only configurator targets
  scripts/dtc: consolidate include path options in Makefile

Pull block fixes from Jens Axboe:
 "A few small fixes for this merge window:

   - Locking imbalance fix for bcache (Shan Hai)

   - A few small fixes for wbt. One is a cleanup/prep, one is a fix for
     an existing issue, and the last two are fixes for changes that went
     into this merge window (me)"

* tag 'for-linus-20180825' of git://git.kernel.dk/linux-block:
  blk-wbt: don't maintain inflight counts if disabled
  blk-wbt: fix has-sleeper queueing check
  blk-wbt: use wq_has_sleeper() for wq active check
  blk-wbt: move disable check into get_limit()
  bcache: release dc->writeback_lock properly in bch_writeback_thread()

Pull UBIFS fix from Richard Weinberger:
 "Remove an empty file from UBIFS source"

* tag 'upstream-4.19-rc1-fix' of git://git.infradead.org/linux-ubifs:
  ubifs: Remove empty file.h

Pull cifs fixes from Steve French:
 "Three small SMB3 fixes, one for stable"

* tag '4.19-rc-smb3' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: update internal module version number for cifs.ko to 2.12
  cifs: check kmalloc before use
  cifs: check if SMB2 PDU size has been padded and suppress the warning
  cifs: create a define for how many iovs we need for an SMB2_open()

This is not normally noticeable, but repeated forks are unnecessarily
expensive because they repeatedly dirty the parent page tables during
the page table copy operation.

It's trivial to just avoid write protecting the page table entry if it
was already not writable.

This patch was inspired by

    https://bugzilla.kernel.org/show_bug.cgi?id=200447

which points to an ancient "waste time re-doing fork" issue in the
presence of lots of signals.

That bug was fixed by Eric Biederman's signal handling series
culminating in commit c3ad2c3b ("signal: Don't restart fork when
signals come in"), but the unnecessary work for repeated forks is still
work just fixing, particularly since the fix is trivial.

Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

At the point where r is being checked for different values, r is always
going to be equal to 2 as the previous if statements jump to end or end1
if r is not 2.  Hence the assignment to err can be simplified to just
err an assignment without any checks on the value or r.

Detected by CoverityScan, CID#1226737 ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Tejun Heo wrote:
>
> I asked Jens whether he could take care of the libata tree and he
> thankfully agreed, so, from now on, Jens will be the libata
> maintainer.
>
> Thanks a lot!

Thanks for your work in this area. I still remember the first linux
storage summit we did in Vancouver 2001, Tejun was invited to talk about
his libata error handling work. Before that, it was basically a crap
shoot if we recovered properly or not... A lot of water has flown under
the bridge since then!

Here's an "official" patch. Linus, can you apply it?
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull libata updates from Tejun Heo:
 "Nothing too interesting. Mostly ahci and ahci_platform changes, many
  around power management"

* 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata: (22 commits)
  ata: ahci_platform: enable to get and control reset
  ata: libahci_platform: add reset control support
  ata: add an extra argument to ahci_platform_get_resources()
  ata: sata_rcar: Add r8a77965 support
  ata: sata_rcar: exclude setting of PHY registers in Gen3
  ata: sata_rcar: really mask all interrupts on Gen2 and later
  Revert "ata: ahci_platform: allow disabling of hotplug to save power"
  ata: libahci: Allow reconfigure of DEVSLP register
  ata: libahci: Correct setting of DEVSLP register
  ata: ahci: Enable DEVSLP by default on x86 with SLP_S0
  ata: ahci: Support state with min power but Partial low power state
  Revert "ata: ahci_platform: convert kcalloc to devm_kcalloc"
  ata: sata_rcar: Add rudimentary Runtime PM support
  ata: sata_rcar: Provide a short-hand for &pdev->dev
  ata: Only output sg element mapped number in verbose debug
  ata: Guard ata_scsi_dump_cdb() by ATA_VERBOSE_DEBUG
  ata: ahci_platform: convert kcalloc to devm_kcalloc
  ata: ahci_platform: convert kzallloc to kcalloc
  ata: ahci_platform: correct parameter documentation for ahci_platform_shutdown
  libata: remove ata_sff_data_xfer_noirq()
  ...

Pull cgroup updates from Tejun Heo:
 "Just one commit from Steven to take out spin lock from trace event
  handlers"

* 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup/tracing: Move taking of spin lock out of trace event handlers

Pull workqueue updates from Tejun Heo:
 "Over the lockdep cross-release churn, workqueue lost some of the
  existing annotations. Johannes Berg restored it and also improved
  them"

* 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: re-add lockdep dependencies for flushing
  workqueue: skip lockdep wq dependency in cancel_work_sync()