@bytes also holds the return value from iomap_write_end, which can
contain a negative error value.  As @bytes is always less than the page
size even the signed type can hold the entire possible range.

Fixes: c6f40468 ("fsdax: decouple zeroing from the iomap buffered I/O code")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211208091203.2927754-1-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

No driver is left using the external pgmap refcount, so remove the
code to support it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211028151017.50234-1-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

The file system DAX code now does not require the block code.  So allow
building a kernel with fuse DAX but not block layer.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-30-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Only build the block based iomap code if CONFIG_BLOCK is set.  Currently
that is always the case, but it will change soon.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-29-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

The DAX device <-> block device association is only enabled if
CONFIG_BLOCK is enabled.  Update dax.h to account for that and use
the right conditions for the fs_put_dax stub as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-28-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Remove the last user of ->bdev in dax.c by requiring the file system to
pass in an address that already includes the DAX offset.  As part of the
only set ->bdev or ->daxdev when actually required in the ->iomap_begin
methods.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> [erofs]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-27-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Prepare for the removal of the block_device from the DAX I/O path by
returning the partition offset from fs_dax_get_by_bdev so that the file
systems have it at hand for use during I/O.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-26-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Add a flag so that the file system can easily detect DAX operations
based just on the iomap operation requested instead of looking at
inode state using IS_DAX.  This will be needed to apply the to be
added partition offset only for operations that actually use DAX,
but not things like fiemap that are based on the block device.
In the long run it should also allow turning the bdev, dax_dev
and inline_data into a union.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-25-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

To prepare for looking at the IOMAP_DAX flag in xfs_bmbt_to_iomap pass in
the input mapping flags to xfs_bmbt_to_iomap.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-24-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

While the buffered write iomap ops do work due to the fact that zeroing
never allocates blocks, the DAX zeroing should use the direct ops just
like actual DAX I/O.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-23-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Hide the DAX device lookup from the xfs_super.c code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20211129102203.2243509-22-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Only call fs_dax_get_by_bdev once the sbi has been allocated and remove
the need for the dax_dev local variable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-21-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Only call fs_dax_get_by_bdev once the sbi has been allocated and remove
the need for the dax_dev local variable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-20-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Unshare the DAX and iomap buffered I/O page zeroing code.  This code
previously did a IS_DAX check deep inside the iomap code, which in
fact was the only DAX check in the code.  Instead move these checks
into the callers.  Most callers already have DAX special casing anyway
and XFS will need it for reflink support as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-19-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Factor out a helper for the "manual" zeroing of a DAX range to clean
up dax_iomap_zero a lot.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-18-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

The file relative offset must have the same alignment as the storage
offset, so use that and get rid of the call to iomap_sector.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-17-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Add helpers to prepare for using different DAX operations.
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
[hch: split from a larger patch + slight cleanups]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-16-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Replace the two steps of dax_iomap_sector and bdev_dax_pgoff with a
single dax_iomap_pgoff helper that avoids lots of cumbersome sector
conversions.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-15-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Just pass the vm_fault and iomap_iter structures, and figure out the rest
locally.  Note that this requires moving dax_iomap_sector up in the file.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-14-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Despite its name copy_user_page expected kernel addresses, which is what
we already have.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-13-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Add a helper to perform the entire remapping for DAX accesses.  This
helper open codes bdev_dax_pgoff given that the alignment checks have
already been done by the submitting file system and don't need to be
repeated.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20211129102203.2243509-12-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Add a helper to perform the entire remapping for DAX accesses.  This
helper open codes bdev_dax_pgoff given that the alignment checks have
already been done by the submitting file system and don't need to be
repeated.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20211129102203.2243509-11-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Add a helper to perform the entire remapping for DAX accesses.  This
helper open codes bdev_dax_pgoff given that the alignment checks have
already been done by the submitting file system and don't need to be
repeated.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20211129102203.2243509-10-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Just open code the block size and dax_dev == NULL checks in the callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> [erofs]
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-9-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Factor out another DAX setup helper to simplify future changes.  Also
move the experimental warning after the checks to not clutter the log
too much if the setup failed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-8-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

fs_dax_get_by_bdev is the primary interface to find a dax device for a
block device, so move the partition alignment check there instead of
wiring it up through ->dax_supported.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-7-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Drivers that register a dax_dev should make sure it works, no need
to double check from the file system.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-6-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Replace the dax_host_hash with an xarray indexed by the pointer value
of the gendisk, and require explicitly calls from the block drivers that
want to associate their gendisk with a dax_device.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-5-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

CONFIG_DAX_DRIVER only selects CONFIG_DAX now, so remove it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20211129102203.2243509-4-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

The device mapper DAX support is all hanging off a block device and thus
can't be used with device dax.  Make it depend on CONFIG_FS_DAX instead
of CONFIG_DAX_DRIVER.  This also means that bdev_dax_pgoff only needs to
be built under CONFIG_FS_DAX now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20211129102203.2243509-3-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Make sure ->dax_dev is NULL on error so that the cleanup path doesn't
trip over an ERR_PTR.
Reported-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211129102203.2243509-2-hch@lst.deSigned-off-by: Dan Williams <dan.j.williams@intel.com>

The /sys/class/dax compatibility option has shipped in the kernel for 4
years now which should be sufficient time for tools to abandon the old
ABI in favor of the /sys/bus/dax device-model. Delete it now and see if
anyone screams.

Since this compatibility option shipped there has been more reports of
users being surprised by the compat ABI than surprised by the "new", so
the compat infrastructure has outlived its usefulness. Recall that
/sys/bus/dax device-model is required for the dax kmem driver which
allows PMEM to be used as "System RAM".

The following projects were known to have a dependency on /sys/class/dax
and have dropped their dependency as of the listed version:

- ndctl (including libndctl, daxctl, and libdaxctl): v64+
- fio: v3.13+
- pmdk: v1.5.2+

As further evidence this option is no longer needed some distributions
have already stopped enabling CONFIG_DEV_DAX_PMEM_COMPAT.

Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Reported-by: Vishal Verma <vishal.l.verma@intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Link: https://lore.kernel.org/r/163701116195.3784476.726128179293466337.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Add Kconfig support for -Wimplicit-fallthrough for both GCC and Clang.

The compiler option is under configuration CC_IMPLICIT_FALLTHROUGH,
which is enabled by default.

Special thanks to Nathan Chancellor who fixed the Clang bug[1][2]. This
bugfix only appears in Clang 14.0.0, so older versions still contain
the bug and -Wimplicit-fallthrough won't be enabled for them, for now.

This concludes a long journey and now we are finally getting rid
of the unintentional fallthrough bug-class in the kernel, entirely. :)

Link: https://github.com/llvm/llvm-project/commit/9ed4a94d6451046a51ef393cd62f00710820a7e8 [1]
Link: https://bugs.llvm.org/show_bug.cgi?id=51094 [2]
Link: https://github.com/KSPP/linux/issues/115
Link: https://github.com/ClangBuiltLinux/linux/issues/236Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull xfs cleanups from Darrick Wong:
 "The most 'exciting' aspect of this branch is that the xfsprogs
  maintainer and I have worked through the last of the code
  discrepancies between kernel and userspace libxfs such that there are
  no code differences between the two except for #includes.

  IOWs, diff suffices to demonstrate that the userspace tools behave the
  same as the kernel, and kernel-only bits are clearly marked in the
  /kernel/ source code instead of just the userspace source.

  Summary:

   - Clean up open-coded swap() calls.

   - A little bit of #ifdef golf to complete the reunification of the
     kernel and userspace libxfs source code"

* tag 'xfs-5.16-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: sync xfs_btree_split macros with userspace libxfs
  xfs: #ifdef out perag code for userspace
  xfs: use swap() to make dabtree code cleaner

Pull more parisc fixes from Helge Deller:
 "Fix a build error in stracktrace.c, fix resolving of addresses to
  function names in backtraces, fix single-stepping in assembly code and
  flush userspace pte's when using set_pte_at()"

* tag 'for-5.16/parisc-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc/entry: fix trace test in syscall exit path
  parisc: Flush kernel data mapping in set_pte_at() when installing pte for user page
  parisc: Fix implicit declaration of function '__kernel_text_address'
  parisc: Fix backtrace to always include init funtion names

Pull arch/sh updates from Rich Felker.

* tag 'sh-for-5.16' of git://git.libc.org/linux-sh:
  sh: pgtable-3level: Fix cast to pointer from integer of different size
  sh: fix READ/WRITE redefinition warnings
  sh: define __BIG_ENDIAN for math-emu
  sh: math-emu: drop unused functions
  sh: fix kconfig unmet dependency warning for FRAME_POINTER
  sh: Cleanup about SPARSE_IRQ
  sh: kdump: add some attribute to function
  maple: fix wrong return value of maple_bus_init().
  sh: boot: avoid unneeded rebuilds under arch/sh/boot/compressed/
  sh: boot: add intermediate vmlinux.bin* to targets instead of extra-y
  sh: boards: Fix the cacography in irq.c
  sh: check return code of request_irq
  sh: fix trivial misannotations

Pull ARM fixes from Russell King:

 - Fix early_iounmap

 - Drop cc-option fallbacks for architecture selection

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 9156/1: drop cc-option fallbacks for architecture selection
  ARM: 9155/1: fix early early_iounmap()

Pull devicetree fixes from Rob Herring:

 - Two fixes due to DT node name changes on Arm, Ltd. boards

 - Treewide rename of Ingenic CGU headers

 - Update ST email addresses

 - Remove Netlogic DT bindings

 - Dropping few more cases of redundant 'maxItems' in schemas

 - Convert toshiba,tc358767 bridge binding to schema

* tag 'devicetree-fixes-for-5.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  dt-bindings: watchdog: sunxi: fix error in schema
  bindings: media: venus: Drop redundant maxItems for power-domain-names
  dt-bindings: Remove Netlogic bindings
  clk: versatile: clk-icst: Ensure clock names are unique
  of: Support using 'mask' in making device bus id
  dt-bindings: treewide: Update @st.com email address to @foss.st.com
  dt-bindings: media: Update maintainers for st,stm32-hwspinlock.yaml
  dt-bindings: media: Update maintainers for st,stm32-cec.yaml
  dt-bindings: mfd: timers: Update maintainers for st,stm32-timers
  dt-bindings: timer: Update maintainers for st,stm32-timer
  dt-bindings: i2c: imx: hardware do not restrict clock-frequency to only 100 and 400 kHz
  dt-bindings: display: bridge: Convert toshiba,tc358767.txt to yaml
  dt-bindings: Rename Ingenic CGU headers to ingenic,*.h

Pull timer fix from Thomas Gleixner:
 "A single fix for POSIX CPU timers to address a problem where POSIX CPU
  timer delivery stops working for a new child task because
  copy_process() copies state information which is only valid for the
  parent task"

* tag 'timers-urgent-2021-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  posix-cpu-timers: Clear task::posix_cputimers_work in copy_process()