Move more nitty gritty DMA implementation details into the common
internal header.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Most of the dma_direct symbols should only be used by direct.c and
mapping.c, so move them to kernel/dma.  In fact more of dma-direct.h
should eventually move, but that will require more coordination with
other subsystems.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Most of dma-debug.h is not required by anything outside of kernel/dma.
Move the four declarations needed by dma-mappin.h or dma-ops providers
into dma-mapping.h and dma-map-ops.h, and move the remainder of the
file to kernel/dma/debug.h.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Just provide a weak default definition of dma_contiguous_early_fixup and
let arm override it.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Merge dma-contiguous.h into dma-map-ops.h, after removing the comment
describing the contiguous allocator into kernel/dma/contigous.c.
Signed-off-by: Christoph Hellwig <hch@lst.de>

dma_contiguous_set_default contains a trivial assignment, and has a
single caller that is compiled if CONFIG_CMA_DMA is enabled.
Signed-off-by: Christoph Hellwig <hch@lst.de>

dev_set_cma_area contains a trivial assignment.  It has just three
callers that all have a non-NULL device and depend on CONFIG_DMA_CMA,
so remove the wrapper.
Signed-off-by: Christoph Hellwig <hch@lst.de>

dma_declare_contiguous is a trivial wrapper around
dma_contiguous_reserve_area and just has a single caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Split out all the bits that are purely for dma_map_ops implementations
and related code into a new <linux/dma-map-ops.h> header so that they
don't get pulled into all the drivers.  That also means the architecture
specific <asm/dma-mapping.h> is not pulled in by <linux/dma-mapping.h>
any more, which leads to a missing includes that were pulled in by the
x86 or arm versions in a few not overly portable drivers.
Signed-off-by: Christoph Hellwig <hch@lst.de>

On an embedded system with a tiny (1 MiB) CMA area for video memory, and
a simple enough video pipeline, we can decrease the CMA_ALIGNMENT by a
factor of 2 to avoid wasting memory, as all the allocations for video
buffers will be of the exact same size (dictated by the size of the
screen).
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Use dma_alloc_pages to allocate DMAable pages instead of hoping that
the architecture either has GFP_DMA32 or not more than 4G of memory.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Implement the alloc_noncoherent method to provide memory that is neither
coherent not contiguous.
Signed-off-by: Christoph Hellwig <hch@lst.de>

This will allow IOMMU drivers to allocate non-contigous memory and
return a vmapped virtual address.
Signed-off-by: Christoph Hellwig <hch@lst.de>

This API is the equivalent of alloc_pages, except that the returned memory
is guaranteed to be DMA addressable by the passed in device.  The
implementation will also be used to provide a more sensible replacement
for DMA_ATTR_NON_CONSISTENT flag.

Additionally dma_alloc_noncoherent is switched over to use dma_alloc_pages
as its backend.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> (MIPS part)

All users are gone now, remove the API.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> (MIPS part)

Use the new non-coherent DMA API including proper ownership transfers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Use the new non-coherent DMA API including proper ownership transfers.
This includes adding additional calls to dma_sync_desc_dev as the
old syncing was rather ad-hoc.

Thanks to Thomas Bogendoerfer for debugging the ownership transfer
issues.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Use the new non-coherent DMA API including proper ownership transfers.
This includes moving the DMA helpers to lib82596 based of an ifdef to
avoid include order problems.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> (SNI part)

Use the new non-coherent DMA API including proper ownership transfers.
This also means we can allocate the buffer memory with the proper
direction instead of bidirectional.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Use the new non-coherent DMA API including proper ownership transfers.
This also means we can allocate the memory as DMA_TO_DEVICE instead
of bidirectional.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Add a new API to allocate and free memory that is guaranteed to be
addressable by a device, but which potentially is not cache coherent
for DMA.

To transfer ownership to and from the device, the existing streaming
DMA API calls dma_sync_single_for_device and dma_sync_single_for_cpu
must be used.

For now the new calls are implemented on top of dma_alloc_attrs just
like the old-noncoherent API, but once all drivers are switched to
the new API it will be replaced with a better working implementation
that is available on all architectures.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Switch the 53c700 driver to only use non-coherent descriptor memory if it
really has to because dma_alloc_coherent fails.  This doesn't matter for
any of the platforms it runs on currently, but that will change soon.

To help with this two new helpers to transfer ownership to and from the
device are added that abstract the syncing of the non-coherent memory.
The two current bidirectional cases are mapped to transfers to the
device, as that appears to what they are used for.  Note that for parisc,
which is the only architecture this driver needs to use non-coherent
memory on, the direction argument of dma_cache_sync is ignored, so this
will not change behavior in any way.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

This allows us to get rid of the LIB82596_DMA_ATTR defined and prepare
for untangling the coherent vs non-coherent DMA allocation API.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> (SNI part)

The au1000-eth driver contains none of the manual cache synchronization
required for using DMA_ATTR_NON_CONSISTENT.  From what I can tell it
can be used on both dma coherent and non-coherent DMA platforms, but
I suspect it has been buggy on the non-coherent platforms all along.
Signed-off-by: Christoph Hellwig <hch@lst.de>

DMA_ATTR_NON_CONSISTENT is a no-op except on PA-RISC and a few MIPS
configs, so don't set it in this ARM specific driver part.
Signed-off-by: Christoph Hellwig <hch@lst.de>

DMA_ATTR_NON_CONSISTENT is a no-op except on PA-RISC and a few MIPS
configs, so don't set it in this ARM specific driver.
Signed-off-by: Christoph Hellwig <hch@lst.de>

To prevent a compiler error when a method call alloc_pages is
added (which I plan to for the dma_map_ops).
Signed-off-by: Christoph Hellwig <hch@lst.de>

Merge branch 'master' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into dma-mapping-for-next

Pull in the latest 5.9 tree for the commit to revert the
V4L2_FLAG_MEMORY_NON_CONSISTENT uapi addition.

Switch the omap1510 platform ohci device to use dma_direct_set_offset
to set the DMA offset instead of using direct hooks into the DMA
mapping code and remove the now unused hooks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Acked-by: Tony Lindgren <tony@atomide.com>

Move the comment documenting dma_addr_t away from the dma_map_ops
definition which isn't very related to it, and toward DMA_MAPPING_ERROR,
which is somewhat related.  Add a little blurb about DMA_MAPPING_ERROR
as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>

Move the valid_dma_direction helper to a more suitable header, and
clean it up to use the proper enum as well as removing pointless braces.
Signed-off-by: Christoph Hellwig <hch@lst.de>

This value is only used by a PCMCIA driver and not very useful.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dominik Brodowski <linux@dominikbrodwski.net>

Pull MMC fix from Ulf Hansson:
 "Fix build warning in mmc_spi when CONFIG_HAS_DMA is unset"

* tag 'mmc-v5.9-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: mmc_spi: Fix mmc_spi_dma_alloc() return type for !HAS_DMA

Pull media fixes from Mauro Carvalho Chehab:

 - fix a regression at the CEC adapter core

 - two uAPI patches (one revert) for changes in this development cycle

* tag 'media/v5.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
  media: dt-bindings: media: imx274: Convert to json-schema
  media: media/v4l2: remove V4L2_FLAG_MEMORY_NON_CONSISTENT flag
  media: cec-adap.c: don't use flush_scheduled_work()

Pull sound fixes from Takashi Iwai:
 "Just a handful small device-specific fixes including a couple of
  reverts"

* tag 'sound-5.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  Revert "ALSA: usb-audio: Disable Lenovo P620 Rear line-in volume control"
  Revert "ALSA: hda - Fix silent audio output and corrupted input on MSI X570-A PRO"
  ALSA: usb-audio: Add delay quirk for H570e USB headsets
  ALSA: hda/realtek: Enable front panel headset LED on Lenovo ThinkStation P520
  ALSA: hda/realtek - Couldn't detect Mic if booting with headset plugged
  ALSA: asihpi: fix iounmap in error handler

Commit 09854ba9 ("mm: do_wp_page() simplification") reorganized all
the code around the page re-use vs copy, but in the process also moved
the final unlock_page() around to after the wp_page_reuse() call.

That normally doesn't matter - but it means that the unlock_page() is
now done after releasing the page table lock.  Again, not a big deal,
you'd think.

But it turns out that it's very wrong indeed, because once we've
released the page table lock, we've basically lost our only reference to
the page - the page tables - and it could now be free'd at any time.  We
do hold the mmap_sem, so no actual unmap() can happen, but madvise can
come in and a MADV_DONTNEED will zap the page range - and free the page.

So now the page may be free'd just as we're unlocking it, which in turn
will usually trigger a "Bad page state" error in the freeing path.  To
make matters more confusing, by the time the debug code prints out the
page state, the unlock has typically completed and everything looks fine
again.

This all doesn't happen in any normal situations, but it does trigger
with the dirtyc0w_child LTP test.  And it seems to trigger much more
easily (but not expclusively) on s390 than elsewhere, probably because
s390 doesn't do the "batch pages up for freeing after the TLB flush"
that gives the unlock_page() more time to complete and makes the race
harder to hit.

Fixes: 09854ba9 ("mm: do_wp_page() simplification")
Link: https://lore.kernel.org/lkml/a46e9bbef2ed4e17778f5615e818526ef848d791.camel@redhat.com/
Link: https://lore.kernel.org/linux-mm/c41149a8-211e-390b-af1d-d5eee690fecb@linux.alibaba.com/Reported-by: Qian Cai <cai@redhat.com>
Reported-by: Alex Shi <alex.shi@linux.alibaba.com>
Bisected-and-analyzed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull bootconfig fixes from Steven Rostedt:
 "A couple of fixes for bootconfig.

  Masami discovered two bugs which this fixes and he added tests to
  cover these issues.

   - Fix a bug that breaks bootconfig tree nodes

   - Fix a bug that does not truncate whitespace properly

   - Add tests to cover the above two cases"

* tag 'trace-v5.9-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tools/bootconfig: Add testcase for tailing space
  tools/bootconfig: Add testcases for repeated key with brace
  lib/bootconfig: Fix to remove tailing spaces after value
  lib/bootconfig: Fix a bug of breaking existing tree nodes

Merge tag 'for-5.9/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - DM core fix for incorrect double bio splitting. Keep "fixing" this
   because past attempts didn't fully appreciate the liability relative
   to recursive bio splitting. This fix limits DM's bio splitting to a
   single method and does _not_ use blk_queue_split() for normal IO.

 - DM crypt Documentation updates for features added during 5.9 merge.

* tag 'for-5.9/dm-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm crypt: document encrypted keyring key option
  dm crypt: document new no_workqueue flags
  dm: fix comment in dm_process_bio()
  dm: fix bio splitting and its bio completion order for regular IO

Pull btrfs fixes from David Sterba:
 "syzkaller started to hit us with reports, here's a fix for one type
  (stack overflow when printing checksums on read error).

  The other patch is a fix for sysfs object, we have a test for that and
  it leads to a crash."

* tag 'for-5.9-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix put of uninitialized kobject after seed device delete
  btrfs: fix overflow when copying corrupt csums for a message

This completes the split of the non-present and present pte cases by
moving the check for the source pte being present into the single
caller, which also means that we clearly separate out the very different
return value case for a non-present pte.

The present pte case currently always succeeds.

This is a pure code re-organization with no semantic change: the intent
is to make it much easier to add a new return case to the present pte
case for when we do early COW at page table copy time.

This was split out from the previous commit simply to make it easy to
visually see that there were no semantic changes from this code
re-organization.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>