DAX PMDs have been disabled since Jan Kara introduced DAX radix tree based
locking.  This patch allows DAX PMDs to participate in the DAX radix tree
based locking scheme so that they can be re-enabled using the new struct
iomap based fault handlers.

There are currently three types of DAX 4k entries: 4k zero pages, 4k DAX
mappings that have an associated block allocation, and 4k DAX empty
entries.  The empty entries exist to provide locking for the duration of a
given page fault.

This patch adds three equivalent 2MiB DAX entries: Huge Zero Page (HZP)
entries, PMD DAX entries that have associated block allocations, and 2 MiB
DAX empty entries.

Unlike the 4k case where we insert a struct page* into the radix tree for
4k zero pages, for HZP we insert a DAX exceptional entry with the new
RADIX_DAX_HZP flag set.  This is because we use a single 2 MiB zero page in
every 2MiB hole mapping, and it doesn't make sense to have that same struct
page* with multiple entries in multiple trees.  This would cause contention
on the single page lock for the one Huge Zero Page, and it would break the
page->index and page->mapping associations that are assumed to be valid in
many other places in the kernel.

One difficult use case is when one thread is trying to use 4k entries in
radix tree for a given offset, and another thread is using 2 MiB entries
for that same offset.  The current code handles this by making the 2 MiB
user fall back to 4k entries for most cases.  This was done because it is
the simplest solution, and because the use of 2MiB pages is already
opportunistic.

If we were to try to upgrade from 4k pages to 2MiB pages for a given range,
we run into the problem of how we lock out 4k page faults for the entire
2MiB range while we clean out the radix tree so we can insert the 2MiB
entry.  We can solve this problem if we need to, but I think that the cases
where both 2MiB entries and 4K entries are being used for the same range
will be rare enough and the gain small enough that it probably won't be
worth the complexity.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

No functional change.

The static functions put_locked_mapping_entry() and
put_unlocked_mapping_entry() will soon be used in error cases in
grab_mapping_entry(), so move their definitions above this function.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

The RADIX_DAX_* defines currently mostly live in fs/dax.c, with just
RADIX_DAX_ENTRY_LOCK being in include/linux/dax.h so it can be used in
mm/filemap.c.  When we add PMD support, though, mm/filemap.c will also need
access to the RADIX_DAX_PTE type so it can properly construct a 4k sized
empty entry.

Instead of shifting the defines between dax.c and dax.h as they are
individually used in other code, just move them wholesale to dax.h so
they'll be available when we need them.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Currently iomap_end() doesn't do anything for DAX page faults for both ext2
and XFS.  ext2_iomap_end() just checks for a write underrun, and
xfs_file_iomap_end() checks to see if it needs to finish a delayed
allocation.  However, in the future iomap_end() calls might be needed to
make sure we have balanced allocations, locks, etc.  So, add calls to
iomap_end() with appropriate error handling to dax_iomap_fault().
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: NJan Kara <jack@suse.cz>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

To be able to correctly calculate the sector from a file position and a
struct iomap there is a complex little bit of logic that currently happens
in both dax_iomap_actor() and dax_iomap_fault().  This will need to be
repeated yet again in the DAX PMD fault handler when it is added, so break
it out into a helper function.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

The recently added DAX functions that use the new struct iomap data
structure were named iomap_dax_rw(), iomap_dax_fault() and
iomap_dax_actor().  These are actually defined in fs/dax.c, though, so
should be part of the "dax" namespace and not the "iomap" namespace.
Rename them to dax_iomap_rw(), dax_iomap_fault() and dax_iomap_actor()
respectively.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: NDave Chinner <david@fromorbit.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

dax_pmd_fault() is the old struct buffer_head + get_block_t based 2 MiB DAX
fault handler.  This fault handler has been disabled for several kernel
releases, and support for PMDs will be reintroduced using the struct iomap
interface instead.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

DAX radix tree locking currently locks entries based on the unique
combination of the 'mapping' pointer and the pgoff_t 'index' for the entry.
This works for PTEs, but as we move to PMDs we will need to have all the
offsets within the range covered by the PMD to map to the same bit lock.
To accomplish this, for ranges covered by a PMD entry we will instead lock
based on the page offset of the beginning of the PMD entry.  The 'mapping'
pointer is still used in the same way.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

No functional change.

Consistently use the variable name 'entry' instead of 'ret' for DAX radix
tree entries.  This was already happening in most of the code, so update
get_unlocked_mapping_entry(), grab_mapping_entry() and
dax_unlock_mapping_entry().
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Don't take down the kernel if we get an invalid 'from' and 'length'
argument pair.  Just warn once and return an error.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

The global 'wait_table' variable is only used within fs/dax.c, and
generates the following sparse warning:

fs/dax.c:39:19: warning: symbol 'wait_table' was not declared. Should it be static?

Make it static so it has scope local to fs/dax.c, and to make sparse happy.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

DAX PMD support was added via the following commit:

commit e7b1ea2a ("ext2: huge page fault support")

I believe this path to be untested as ext2 doesn't reliably provide block
allocations that are aligned to 2MiB.  In my testing I've been unable to
get ext2 to actually fault in a PMD.  It always fails with a "pfn
unaligned" message because the sector returned by ext2_get_block() isn't
aligned.

I've tried various settings for the "stride" and "stripe_width" extended
options to mkfs.ext2, without any luck.

Since we can't reliably get PMDs, remove support so that we don't have an
untested code path that we may someday traverse when we happen to get an
aligned block allocation.  This should also make 4k DAX faults in ext2 a
bit faster since they will no longer have to call the PMD fault handler
only to get a response of VM_FAULT_FALLBACK.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Now that ext4 properly sets bh.b_size when we call get_block() for a hole,
rely on that value and remove the buffer_size_valid() sanity check.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <david@fromorbit.com>

When DAX calls _ext4_get_block() and the file offset points to a hole we
currently don't set bh->b_size.  This is current worked around via
buffer_size_valid() in fs/dax.c.

_ext4_get_block() has the hole size information from ext4_map_blocks(), so
populate bh->b_size so we can remove buffer_size_valid() in a later patch.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NDave Chinner <david@fromorbit.com>

Pull befs fixes from Luis de Bethencourt:
 "I recently took maintainership of the befs file system [0]. This is
  the first time I send you a git pull request, so please let me know if
  all the below is OK.

  Salah Triki and myself have been cleaning the code and fixing a few
  small bugs.

  Sorry I couldn't send this sooner in the merge window, I was waiting
  to have my GPG key signed by kernel members at ELCE in Berlin a few
  days ago."

[0] https://lkml.org/lkml/2016/7/27/502

* tag 'befs-v4.9-rc1' of git://github.com/luisbg/linux-befs: (39 commits)
  befs: befs: fix style issues in datastream.c
  befs: improve documentation in datastream.c
  befs: fix typos in datastream.c
  befs: fix typos in btree.c
  befs: fix style issues in super.c
  befs: fix comment style
  befs: add check for ag_shift in superblock
  befs: dump inode_size superblock information
  befs: remove unnecessary initialization
  befs: fix typo in befs_sb_info
  befs: add flags field to validate superblock state
  befs: fix typo in befs_find_key
  befs: remove unused BEFS_BT_PARMATCH
  fs: befs: remove ret variable
  fs: befs: remove in vain variable assignment
  fs: befs: remove unnecessary *befs_sb variable
  fs: befs: remove useless initialization to zero
  fs: befs: remove in vain variable assignment
  fs: befs: Insert NULL inode to dentry
  fs: befs: Remove useless calls to brelse in befs_find_brun_dblindirect
  ...

Pull gcc plugins update from Kees Cook:
 "This adds a new gcc plugin named "latent_entropy". It is designed to
  extract as much possible uncertainty from a running system at boot
  time as possible, hoping to capitalize on any possible variation in
  CPU operation (due to runtime data differences, hardware differences,
  SMP ordering, thermal timing variation, cache behavior, etc).

  At the very least, this plugin is a much more comprehensive example
  for how to manipulate kernel code using the gcc plugin internals"

* tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  latent_entropy: Mark functions with __latent_entropy
  gcc-plugins: Add latent_entropy plugin

Pull MIPS updates from Ralf Baechle:
 "This is the main MIPS pull request for 4.9:

  MIPS core arch code:
   - traps: 64bit kernels should read CP0_EBase 64bit
   - traps: Convert ebase to KSEG0
   - c-r4k: Drop bc_wback_inv() from icache flush
   - c-r4k: Split user/kernel flush_icache_range()
   - cacheflush: Use __flush_icache_user_range()
   - uprobes: Flush icache via kernel address
   - KVM: Use __local_flush_icache_user_range()
   - c-r4k: Fix flush_icache_range() for EVA
   - Fix -mabi=64 build of vdso.lds
   - VDSO: Drop duplicated -I*/-E* aflags
   - tracing: move insn_has_delay_slot to a shared header
   - tracing: disable uprobe/kprobe on compact branch instructions
   - ptrace: Fix regs_return_value for kernel context
   - Squash lines for simple wrapper functions
   - Move identification of VP(E) into proc.c from smp-mt.c
   - Add definitions of SYNC barrierstype values
   - traps: Ensure full EBase is written
   - tlb-r4k: If there are wired entries, don't use TLBINVF
   - Sanitise coherentio semantics
   - dma-default: Don't check hw_coherentio if device is non-coherent
   - Support per-device DMA coherence
   - Adjust MIPS64 CAC_BASE to reflect Config.K0
   - Support generating Flattened Image Trees (.itb)
   - generic: Introduce generic DT-based board support
   - generic: Convert SEAD-3 to a generic board
   - Enable hardened usercopy
   - Don't specify STACKPROTECTOR in defconfigs

  Octeon:
   - Delete dead code and files across the platform.
   - Change to use all memory into use by default.
   - Rename upper case variables in setup code to lowercase.
   - Delete legacy hack for broken bootloaders.
   - Leave maintaining the link state to the actual ethernet/PHY drivers.
   - Add DTS for D-Link DSR-500N.
   - Fix PCI interrupt routing on D-Link DSR-500N.

  Pistachio:
   - Remove ANDROID_TIMED_OUTPUT from defconfig

  TX39xx:
   - Move GPIO setup from .mem_setup() to .arch_init()
   - Convert to Common Clock Framework

  TX49xx:
   - Move GPIO setup from .mem_setup() to .arch_init()
   - Convert to Common Clock Framework

  txx9wdt:
   - Add missing clock (un)prepare calls for CCF

  BMIPS:
   - Add PW, GPIO SDHCI and NAND device node names
   - Support APPENDED_DTB
   - Add missing bcm97435svmb to DT_NONE
   - Rename bcm96358nb4ser to bcm6358-neufbox4-sercom
   - Add DT examples for BCM63268, BCM3368 and BCM6362
   - Add support for BCM3368 and BCM6362

  PCI
   - Reduce stack frame usage
   - Use struct list_head lists
   - Support for CONFIG_PCI_DOMAINS_GENERIC
   - Make pcibios_set_cache_line_size an initcall
   - Inline pcibios_assign_all_busses
   - Split pci.c into pci.c & pci-legacy.c
   - Introduce CONFIG_PCI_DRIVERS_LEGACY
   - Support generic drivers

  CPC
   - Convert bare 'unsigned' to 'unsigned int'
   - Avoid lock when MIPS CM >= 3 is present

  GIC:
   - Delete unused file smp-gic.c

  mt7620:
   - Delete unnecessary assignment for the field "owner" from PCI

  BCM63xx:
   - Let clk_disable() return immediately if clk is NULL

  pm-cps:
   - Change FSB workaround to CPU blacklist
   - Update comments on barrier instructions
   - Use MIPS standard lightweight ordering barrier
   - Use MIPS standard completion barrier
   - Remove selection of sync types
   - Add MIPSr6 CPU support
   - Support CM3 changes to Coherence Enable Register

  SMP:
   - Wrap call to mips_cpc_lock_other in mips_cm_lock_other
   - Introduce mechanism for freeing and allocating IPIs

  cpuidle:
   - cpuidle-cps: Enable use with MIPSr6 CPUs.

  SEAD3:
   - Rewrite to use DT and generic kernel feature.

  USB:
   - host: ehci-sead3: Remove SEAD-3 EHCI code

  FBDEV:
   - cobalt_lcdfb: Drop SEAD3 support

  dt-bindings:
   -  Document a binding for simple ASCII LCDs

  auxdisplay:
   - img-ascii-lcd: driver for simple ASCII LCD displays

  irqchip i8259:
   - i8259: Add domain before mapping parent irq
   - i8259: Allow platforms to override poll function
   - i8259: Remove unused i8259A_irq_pending

  Malta:
   - Rewrite to use DT

  of/platform:
   - Probe "isa" busses by default

  CM:
   - Print CM error reports upon bus errors

  Module:
   - Migrate exception table users off module.h and onto extable.h
   - Make various drivers explicitly non-modular:
   - Audit and remove any unnecessary uses of module.h

  mailmap:
   - Canonicalize to Qais' current email address.

  Documentation:
   - MIPS supports HAVE_REGS_AND_STACK_ACCESS_API

  Loongson1C:
   - Add CPU support for Loongson1C
   - Add board support
   - Add defconfig
   - Add RTC support for Loongson1C board

  All this except one Documentation fix has sat in linux-next and has
  survived Imagination's automated build test system"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (127 commits)
  Documentation: MIPS supports HAVE_REGS_AND_STACK_ACCESS_API
  MIPS: ptrace: Fix regs_return_value for kernel context
  MIPS: VDSO: Drop duplicated -I*/-E* aflags
  MIPS: Fix -mabi=64 build of vdso.lds
  MIPS: Enable hardened usercopy
  MIPS: generic: Convert SEAD-3 to a generic board
  MIPS: generic: Introduce generic DT-based board support
  MIPS: Support generating Flattened Image Trees (.itb)
  MIPS: Adjust MIPS64 CAC_BASE to reflect Config.K0
  MIPS: Print CM error reports upon bus errors
  MIPS: Support per-device DMA coherence
  MIPS: dma-default: Don't check hw_coherentio if device is non-coherent
  MIPS: Sanitise coherentio semantics
  MIPS: PCI: Support generic drivers
  MIPS: PCI: Introduce CONFIG_PCI_DRIVERS_LEGACY
  MIPS: PCI: Split pci.c into pci.c & pci-legacy.c
  MIPS: PCI: Inline pcibios_assign_all_busses
  MIPS: PCI: Make pcibios_set_cache_line_size an initcall
  MIPS: PCI: Support for CONFIG_PCI_DOMAINS_GENERIC
  MIPS: PCI: Use struct list_head lists
  ...

Pull sound fixes from Takashi Iwai:
 "Just a few trivial small fixes"

* tag 'sound-fix-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: line6: fix a crash in line6_hwdep_write()
  ALSA: seq: fix passing wrong pointer in function call of compatibility layer
  ALSA: hda - Fix a failure of micmute led when having multi adcs
  ALSA: line6: Fix POD X3 Live audio input

Pull more misc uaccess and vfs updates from Al Viro:
 "The rest of the stuff from -next (more uaccess work) + assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  score: traps: Add missing include file to fix build error
  fs/super.c: don't fool lockdep in freeze_super() and thaw_super() paths
  fs/super.c: fix race between freeze_super() and thaw_super()
  overlayfs: Fix setting IOP_XATTR flag
  iov_iter: kernel-doc import_iovec() and rw_copy_check_uvector()
  blackfin: no access_ok() for __copy_{to,from}_user()
  arm64: don't zero in __copy_from_user{,_inatomic}
  arm: don't zero in __copy_from_user_inatomic()/__copy_from_user()
  arc: don't leak bits of kernel stack into coredump
  alpha: get rid of tail-zeroing in __copy_user()

Pull cifs fixes from Steve French:
 "Including:

   - nine bug fixes for stable. Some of these we found at the recent two
     weeks of SMB3 test events/plugfests.

   - significant improvements in reconnection (e.g. if server or network
     crashes) especially when mounted with "persistenthandles" or to
     server which advertises Continuous Availability on the share.

   - a new mount option "idsfromsid" which improves POSIX compatibility
     in some cases (when winbind not configured e.g.) by better (and
     faster) fetching uid/gid from acl (when "cifsacl" mount option is
     enabled). NB: we are almost complete work on "cifsacl" (querying
     mode/uid/gid from ACL) for SMB3, but SMB3 support for cifsacl is
     not included in this set.

   - improved handling for SMB3 "credits" (even if server is buggy)

  Still working on two sets of changes:

   - cifsacl enablement for SMB3

   - cleanup of RFC1001 length calculation (so we can handle encryption
     and multichannel and RDMA)

  And a couple of new bugs were reported recently (unrelated to above)
  so will probably have another merge request next week"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6: (21 commits)
  CIFS: Retrieve uid and gid from special sid if enabled
  CIFS: Add new mount option to set owner uid and gid from special sids in acl
  CIFS: Reset read oplock to NONE if we have mandatory locks after reopen
  CIFS: Fix persistent handles re-opening on reconnect
  SMB2: Separate RawNTLMSSP authentication from SMB2_sess_setup
  SMB2: Separate Kerberos authentication from SMB2_sess_setup
  Expose cifs module parameters in sysfs
  Cleanup missing frees on some ioctls
  Enable previous version support
  Do not send SMB3 SET_INFO request if nothing is changing
  SMB3: Add mount parameter to allow user to override max credits
  fs/cifs: reopen persistent handles on reconnect
  Clarify locking of cifs file and tcon structures and make more granular
  Fix regression which breaks DFS mounting
  fs/cifs: keep guid when assigning fid to fileinfo
  SMB3: GUIDs should be constructed as random but valid uuids
  Set previous session id correctly on SMB3 reconnect
  cifs: Limit the overall credit acquired
  Display number of credits available
  Add way to query creation time of file via cifs xattr
  ...

Pull btrfs fixes from Chris Mason:
 "Some fixes from Omar and Dave Sterba for our new free space tree.

  This isn't heavily used yet, but as we move toward making it the new
  default we wanted to nail down an endian bug"

* 'for-linus-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: tests: uninline member definitions in free_space_extent
  btrfs: tests: constify free space extent specs
  Btrfs: expand free space tree sanity tests to catch endianness bug
  Btrfs: fix extent buffer bitmap tests on big-endian systems
  Btrfs: catch invalid free space trees
  Btrfs: fix mount -o clear_cache,space_cache=v2
  Btrfs: fix free space tree bitmaps on big-endian systems

score images fail to build as follows.

arch/score/kernel/traps.c: In function 'show_stack':
arch/score/kernel/traps.c:55:3: error:
	implicit declaration of function '__get_user'

__get_user() is declared in asm/uaccess.h, which was previously included
through asm/module.h.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 88dd4a74 ("score: separate extable.h, switch module.h to it")
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

sb_wait_write()->percpu_rwsem_release() fools lockdep to avoid the
false-positives. Now that xfs was fixed by Dave's commit dbad7c99
("xfs: stop holding ILOCK over filldir callbacks") we can remove it and
change freeze_super() and thaw_super() to run with s_writers.rw_sem locks
held; we add two trivial helpers for that, lockdep_sb_freeze_release()
and lockdep_sb_freeze_acquire().

xfstests-dev/check `grep -il freeze tests/*/???` does not trigger any
warning from lockdep.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Pull overlayfs updates from Miklos Szeredi:
 "This update contains fixes to the "use mounter's permission to access
  underlying layers" area, and miscellaneous other fixes and cleanups.

  No new features this time"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: use vfs_get_link()
  vfs: add vfs_get_link() helper
  ovl: use generic_readlink
  ovl: explain error values when removing acl from workdir
  ovl: Fix info leak in ovl_lookup_temp()
  ovl: during copy up, switch to mounter's creds early
  ovl: lookup: do getxattr with mounter's permission
  ovl: copy_up_xattr(): use strnlen

Change thaw_super() to check frozen != SB_FREEZE_COMPLETE rather than
frozen == SB_UNFROZEN, otherwise it can race with freeze_super() which
drops sb->s_umount after SB_FREEZE_WRITE to preserve the lock ordering.

In this case thaw_super() will wrongly call s_op->unfreeze_fs() before
it was actually frozen, and call sb_freeze_unlock() which leads to the
unbalanced percpu_up_write(). Unfortunately lockdep can't detect this,
so this triggers misc BUG_ON()'s in kernel/rcu/sync.c.
Reported-and-tested-by: NNikolay Borisov <kernel@kyup.com>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

ovl_fill_super calls ovl_new_inode to create a root inode for the new
superblock before initializing sb->s_xattr.  This wrongly causes
IOP_XATTR to be cleared in i_opflags of the new inode, causing SELinux
to log the following message:

  SELinux: (dev overlay, type overlay) has no xattr support

Fix this by initializing sb->s_xattr and similar fields before calling
ovl_new_inode.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Both import_iovec() and rw_copy_check_uvector() take an array
(typically small and on-stack) which is used to hold an iovec array copy
from userspace. This is to avoid an expensive memory allocation in the
fast path (i.e. few iovec elements).

The caller may have to check whether these functions actually used
the provided buffer or allocated a new one -- but this differs between
the too. Let's just add a kernel doc to clarify what the semantics are
for each function.
Signed-off-by: NVegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Merge tag 'linux-kselftest-4.9-rc1-update' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kselftest updates from Shuah Khan:
 "This update consists of:

   - Fixes and improvements to existing tests

   - Moving code from Documentation to selftests, samples, and tools:

     * Moves dnotify_test, prctl, ptp, vDSO, ia64, watchdog, and
       networking tests from Documentation to selftests.

     * Moves mic/mpssd, misc-devices/mei, timers, watchdog, auxdisplay,
       and blackfin examples from Documentation to samples.

     * Moves accounting, laptops/dslm, and pcmcia/crc32hash tools from
       Documentation to tools.

     * Deletes BUILD_DOCSRC and its dependencies"

* tag 'linux-kselftest-4.9-rc1-update' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (21 commits)
  selftests/futex: Check ANSI terminal color support
  Doc: update 00-INDEX files to reflect the runnable code move
  samples: move blackfin gptimers-example from Documentation
  tools: move pcmcia crc32hash tool from Documentation
  tools: move laptops dslm tool from Documentation
  tools: move accounting tool from Documentation
  samples: move auxdisplay example code from Documentation
  samples: move watchdog example code from Documentation
  samples: move timers example code from Documentation
  samples: move misc-devices/mei example code from Documentation
  samples: move mic/mpssd example code from Documentation
  selftests: Move networking/timestamping from Documentation
  selftests: move watchdog tests from Documentation/watchdog
  selftests: move ia64 tests from Documentation/ia64
  selftests: move vDSO tests from Documentation/vDSO
  selftests: move ptp tests from Documentation/ptp
  selftests: move prctl tests from Documentation/prctl
  selftests: move dnotify_test from Documentation/filesystems
  selftests/timers: Add missing error code assignment before test
  selftests/zram: replace ZRAM_LZ4_COMPRESS
  ...

Pull misc kbuild changes from Michal Marek:
 "Just a few patches on the kbuild.git#misc branch this time:

   - New Coccinelle patch by Nicholas Mc Guire
   - Existing patch fixes by Julia Lawall
   - Minor comment fix by Markus Elfring"

* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
  Coccinelle: flag conditions with no effect
  scripts/coccicheck: Update reference for the corresponding documentation
  Coccinelle: pm_runtime: ensure relevance of pm_runtime reports
  Coccinelle: limit memdup_user transformation to GFP_KERNEL case

Pull kbuild updates from Michal Marek:

 - EXPORT_SYMBOL for asm source by Al Viro.

   This does bring a regression, because genksyms no longer generates
   checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is
   working on a patch to fix this.

   Plus, we are talking about functions like strcpy(), which rarely
   change prototypes.

 - Fixes for PPC fallout of the above by Stephen Rothwell and Nick
   Piggin

 - fixdep speedup by Alexey Dobriyan.

 - preparatory work by Nick Piggin to allow architectures to build with
   -ffunction-sections, -fdata-sections and --gc-sections

 - CONFIG_THIN_ARCHIVES support by Stephen Rothwell

 - fix for filenames with colons in the initramfs source by me.

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits)
  initramfs: Escape colons in depfile
  ppc: there is no clear_pages to export
  powerpc/64: whitelist unresolved modversions CRCs
  kbuild: -ffunction-sections fix for archs with conflicting sections
  kbuild: add arch specific post-link Makefile
  kbuild: allow archs to select link dead code/data elimination
  kbuild: allow architectures to use thin archives instead of ld -r
  kbuild: Regenerate genksyms lexer
  kbuild: genksyms fix for typeof handling
  fixdep: faster CONFIG_ search
  ia64: move exports to definitions
  sparc32: debride memcpy.S a bit
  [sparc] unify 32bit and 64bit string.h
  sparc: move exports to definitions
  ppc: move exports to definitions
  arm: move exports to definitions
  s390: move exports to definitions
  m68k: move exports to definitions
  alpha: move exports to actual definitions
  x86: move exports to actual definitions
  ...

Pull one more documentation update from Jonathan Corbet:
 "A single commit converting the mac80211 DocBook template over to
  Sphinx.  Only 32 more to go..."

* tag 'docs-4.9-2' of git://git.lwn.net/linux:
  docs-rst: sphinxify 802.11 documentation

Pull rdma qedr RoCE driver from Doug Ledford:
 "Early on in the merge window I mentioned I had a backlog of new
  drivers waiting to be reviewed and that, in addition to the hns-roce
  driver, I wanted to get possible a couple more reviewed. I ended up
  only having the time to complete one of the additional drivers.

  During Dave Miller's pull request this go around, there were a series
  of 9 patches to the QLogic qed net driver that add basic support for a
  paired RoCE driver. That support is currently not functional because
  it is missing the matching RoCE driver in the RDMA subsystem. I
  managed to finish that review. However, because it goes against part
  of Dave's net pull, and a part that was accepted a day or two after
  the merge window opened, to apply cleanly it has to be applied to
  either the tip of Dave's net branch, or as I did in this case, I just
  applied it to your master after you had taken Dave's pull request."

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma:
  qedr: Add events support and register IB device
  qedr: Add GSI support
  qedr: Add LL2 RoCE interface
  qedr: Add support for data path
  qedr: Add support for memory registeration verbs
  qedr: Add support for QP verbs
  qedr: Add support for PD,PKEY and CQ verbs
  qedr: Add support for user context verbs
  qedr: Add support for RoCE HW init
  qedr: Add RoCE driver framework

Pull more rdma updates from Doug Ledford:
 "This merge window was the first where Huawei had to try and coordinate
  their patches between their net driver and their new roce driver
  (similar to mlx4 and mlx5).

  They didn't do horribly, but there were some issues (and we knew that
  because they simply didn't know what to do in the beginning). As a
  result, I had a set of patches that depended on some patches that
  normally would have come to you via Dave's tree. Those patches have
  been on netdev@ for a while, so I got Dave to give me his approval to
  send them to you. As such, the other 29 patches I had behind them are
  also now ready to go.

  This catches the hns and hns-roce drivers up to current, and for
  future patches we are working with them to get them up to speed on how
  to do joint driver development so that they don't have these sorts of
  cross tree dependency issues again. BTW, Dave gave me permission to
  add his Acked-by: to the patches against the net tree, but I've had
  this branch through 0day (but not linux-next since it was off by
  itself) and I didn't want to rebase the series just to add Dave's ack
  for the 8 patches in the net area.

  Updates to the hns drivers:

   - Small patch set for hns net driver that the roce patches depend on

   - Various fixes to the hns-roce driver

   - Add connection manager support to the hns-roce driver"

* tag 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (36 commits)
  IB/hns: Fix for removal of redundant code
  IB/hns: Delete the redundant lines in hns_roce_v1_m_qp()
  IB/hns: Fix the bug when platform_get_resource() exec fail
  IB/hns: Update the rq head when modify qp state
  IB/hns: Cq has not been freed
  IB/hns: Validate mtu when modified qp
  IB/hns: Some items of qpc need to take user param
  IB/hns: The Ack timeout need a lower limit value
  IB/hns: Return bad wr while post send failed
  IB/hns: Fix bug of memory leakage for registering user mr
  IB/hns: Modify the init of iboe lock
  IB/hns: Optimize code of aeq and ceq interrupt handle and fix the bug of qpn
  IB/hns: Delete the sqp_start from the structure hns_roce_caps
  IB/hns: Fix bug of clear hem
  IB/hns: Remove unused parameter named qp_type
  IB/hns: Simplify function of pd alloc and qp alloc
  IB/hns: Fix bug of using uninit refcount and free
  IB/hns: Remove parameters of resize cq
  IB/hns: Remove unused parameters in some functions
  IB/hns: Add node_guid definition to the bindings document
  ...

Pull some more input subsystem updates from Dmitry Torokhov:
 "An update to the ALPS driver to support the V8 protocol with
  touchstick, a change for i8042 to skip selftest on many Asus laptops
  which helps to keep their touchpads working after resume, and a couple
  other driver fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: i8042 - skip selftest on ASUS laptops
  Input: melfas_mip4 - add ic_name sysfs attribute
  Input: melfas_mip4 - add maintainer information
  Input: melfas_mip4 - add devicetree binding documentations
  Input: elantech - add Fujitsu Lifebook E556 to force crc_enabled
  Input: synaptics-rmi4 - fix error handling in I2C transport driver
  Input: synaptics-rmi4 - fix error handling in SPI transport driver
  Input: ALPS - add V8 protocol documentation
  Input: ALPS - set DualPoint flag for 74 03 28 devices
  Input: ALPS - allow touchsticks to report pressure
  Input: ALPS - handle 0-pressure 1F events
  Input: ALPS - add touchstick support for SS5 hardware
  Input: elantech - force needed quirks on Fujitsu H760
  Input: elantech - fix Lenovo version typo

Pull RTC updates from Alexandre Belloni:
 "RTC for 4.9

  Subsystem:
   - delete owner assignment in multiple drivers
   - constify rtc_class_ops structures

  Drivers:
   - ac100: support clock-output-names
   - cmos: properly handle ACPI alarms and quirky BIOSes and other fixes
   - ds1307: fix century bit support while staying comaptible with
     previous behaviour by default
   - ds1347: switch to regmap
   - isl12057 is now handled by ds1307
   - omap: support external wakeup
   - rv8803: allow to disable voltage drop detection"

* tag 'rtc-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (25 commits)
  rtc: rv8803: set VDETOFF and SWOFF via device tree
  dt/bindings: Add bindings for Micro Crystal rv8803
  devicetree: Add Micro Crystal AG vendor id
  rtc: cmos: avoid unused function warning
  rtc: ac100: Add NULL checking for devm_kzalloc call
  rtc: ds1347: changed raw spi calls to register map calls
  rtc: cmos: Restore alarm after resume
  rtc: cmos: Clear ACPI-driven alarms upon resume
  rtc: omap: Support ext_wakeup configuration
  rtc: cmos: Initialize hpet timer before irq is registered
  rtc: asm9260: rework locking
  rtc: asm9260: allow COMPILE_TEST
  rtc: constify rtc_class_ops structures
  rtc: ac100: support clock-output-names in device tree binding
  rtc: rx6110: remove owner assignment
  rtc: pic32: Delete owner assignment
  rtc: bq32k: Fix handling of oscillator failure flag
  rtc: bq32k: Use correct mask name for 'minutes' register.
  rtc: sysfs: fix a cast removing the const attribute
  Documentation: dt: Intersil isl12057 is not a trivial device
  ...

Pull more i2c updates from Wolfram Sang:
 "A small update pull request from I2C.

  This adds one comment to a change we did in this merge window to
  handle lockdep better, and pulls in a branch which should have been in
  4.8 already improving DT support for I2C"

* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  gpio: pca953x: add a comment explaining the need for a lockdep subclass
  i2c: core: Add support for 'i2c-bus' subnode
  dt-bindings: i2c: Add support for 'i2c-bus' subnode

Pull more ACPI updates from Rafael Wysocki:
 "This includes a couple of fixes needed after recent changes, two ACPI
  driver fixes (fan and "Processor Aggregator"), an update of the ACPI
  device properties handling code and a new MAINTAINERS entry for ACPI
  on ARM64.

  Specifics:

   - Fix an unused function warning that started to appear after recent
     changes in the ACPI EC driver (Eric Biggers).

   - Fix the KERN_CONT usage in acpi_os_vprintf() that has become
     (particularly) annoying recently (Joe Perches).

   - Fix the fan status checking in the ACPI fan driver to avoid
     returning incorrect error codes sometimes (Srinivas Pandruvada).

   - Fix the ACPI Processor Aggregator driver (PAD) to always let the
     special processor_aggregator driver from Xen take over when running
     as Xen dom0 (Juergen Gross).

   - Update the handling of reference device properties in ACPI by
     allowing empty rows ("holes") to appear in reference property lists
     (Mika Westerberg).

   - Add a new MAINTAINERS entry for ACPI on ARM64 (Lorenzo Pieralisi)"

* tag 'acpi-extra-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  acpi_os_vprintf: Use printk_get_level() to avoid unnecessary KERN_CONT
  ACPI / PAD: don't register acpi_pad driver if running as Xen dom0
  ACPI / property: Allow holes in reference properties
  MAINTAINERS: Add ARM64-specific ACPI maintainers entry
  ACPI / EC: Fix unused function warning when CONFIG_PM_SLEEP=n
  ACPI / fan: Fix error reading cur_state

Pull more power management updates from Rafael Wysocki:
 "This includes a couple of fixes for cpufreq regressions introduced in
  4.8, a rework of the intel_pstate algorithm used on Atom processors
  (that took some time to test) plus a fix and a couple of cleanups in
  that driver, a CPPC cpufreq driver fix, and a some devfreq fixes and
  cleanups (core and exynos-nocp).

  Specifics:

   - Fix two cpufreq regressions causing undesirable changes in behavior
     to appear (one in the core and one in the conservative governor)
     introduced during the 4.8 cycle (Aaro Koskinen, Rafael Wysocki).

   - Fix the way the intel_pstate driver accesses MSRs related to the
     hardware-managed P-states (HWP) feature during the initialization
     which currently is unsafe and may cause the processor to generate a
     general protection fault (Srinivas Pandruvada).

   - Rework the intel_pstate's P-state selection algorithm used on Atom
     processors to avoid known problems with the current one and to make
     the computation more straightforward, which also happens to improve
     performance in multiple benchmarks a bit (Rafael Wysocki).

   - Improve two comments in the intel_pstate driver (Rafael Wysocki).

   - Fix the desired performance computation in the CPPC cpufreq driver
     (Hoan Tran).

   - Fix the devfreq core to avoid printing misleading error messages in
     some cases (Tobias Jakobi).

   - Fix the error code path in devfreq_add_device() to use proper
     locking around list modifications (Axel Lin).

   - Fix a build failure and remove a couple of redundant updates of
     variables in the exynos-nocp devfreq driver (Axel Lin)"

* tag 'pm-extra-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: CPPC: Correct desired_perf calculation
  cpufreq: conservative: Fix next frequency selection
  cpufreq: skip invalid entries when searching the frequency
  cpufreq: intel_pstate: Fix struct pstate_adjust_policy kerneldoc
  cpufreq: intel_pstate: Proportional algorithm for Atom
  PM / devfreq: Skip status update on uninitialized previous_freq
  PM / devfreq: Add proper locking around list_del()
  PM / devfreq: exynos-nocp: Remove redundant code
  PM / devfreq: exynos-nocp: Select REGMAP_MMIO
  cpufreq: intel_pstate: Clarify comment in get_target_pstate_use_performance()
  cpufreq: intel_pstate: Fix unsafe HWP MSR access