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git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux
Pull dma-mapping fixes from Marek Szyprowski:
"Two last minute fixes for the recently modified DMA API infrastructure:
- proper handling of DMA_ATTR_MMIO in dma_iova_unlink() function (me)
- regression fix for the code refactoring related to P2PDMA (Pranjal
Shrivastava)"
* tag 'dma-mapping-6.18-2025-11-27' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
dma-direct: Fix missing sg_dma_len assignment in P2PDMA bus mappings
iommu/dma: add missing support for DMA_ATTR_MMIO for dma_iova_unlink()
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Prior to commit a25e7962db0d7 ("PCI/P2PDMA: Refactor the p2pdma mapping
helpers"), P2P segments were mapped using the pci_p2pdma_map_segment()
helper. This helper was responsible for populating sg->dma_address,
marking the bus address, and also setting sg_dma_len(sg).
The refactor[1] removed this helper and moved the mapping logic directly
into the callers. While iommu_dma_map_sg() was correctly updated to set
the length in the new flow, it was missed in dma_direct_map_sg().
Thus, in dma_direct_map_sg(), the PCI_P2PDMA_MAP_BUS_ADDR case sets the
dma_address and marks the segment, but immediately executes 'continue',
which causes the loop to skip the standard assignment logic at the end:
sg_dma_len(sg) = sg->length;
As a result, when CONFIG_NEED_SG_DMA_LENGTH is enabled, the dma_length
field remains uninitialized (zero) for P2P bus address mappings. This
breaks upper-layer drivers (for e.g. RDMA/IB) that rely on sg_dma_len()
to determine the transfer size.
Fix this by explicitly setting the DMA length in the
PCI_P2PDMA_MAP_BUS_ADDR case before continuing to the next scatterlist
entry.
Fixes: a25e7962db0d7 ("PCI/P2PDMA: Refactor the p2pdma mapping helpers")
Reported-by: Jacob Moroni <jmoroni@google.com>
Signed-off-by: Pranjal Shrivastava <praan@google.com>
[1]
https://lore.kernel.org/all/ac14a0e94355bf898de65d023ccf8a2ad22a3ece.1746424934.git.leon@kernel.org/
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Shivaji Kant <shivajikant@google.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20251126114112.3694469-1-praan@google.com
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Commit 370645f41e6e ("dma-mapping: force bouncing if the kmalloc() size is
not cache-line-aligned") introduced DMA_BOUNCE_UNALIGNED_KMALLOC feature
and permitted architecture specific code configure kmalloc slabs with
sizes smaller than the value of dma_get_cache_alignment().
When that feature is enabled, the physical address of some small
kmalloc()-ed buffers might be not aligned to the CPU cachelines, thus not
really suitable for typical DMA. To properly handle that case a SWIOTLB
buffer bouncing is used, so no CPU cache corruption occurs. When that
happens, there is no point reporting a false-positive DMA-API warning that
the buffer is not properly aligned, as this is not a client driver fault.
[m.szyprowski@samsung.com: replace is_swiotlb_allocated() with is_swiotlb_active(), per Catalin]
Link: https://lkml.kernel.org/r/20251010173009.3916215-1-m.szyprowski@samsung.com
Link: https://lkml.kernel.org/r/20251009141508.2342138-1-m.szyprowski@samsung.com
Fixes: 370645f41e6e ("dma-mapping: force bouncing if the kmalloc() size is not cache-line-aligned")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Inki Dae <m.szyprowski@samsung.com>
Cc: Robin Murohy <robin.murphy@arm.com>
Cc: "Isaac J. Manjarres" <isaacmanjarres@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux
Pull dma-mapping updates from Marek Szyprowski:
- Refactoring of DMA mapping API to physical addresses as the primary
interface instead of page+offset parameters
This gets much closer to Matthew Wilcox's long term wish for
struct-pageless IO to cacheable DRAM and is supporting memdesc
project which seeks to substantially transform how struct page works.
An advantage of this approach is the possibility of introducing
DMA_ATTR_MMIO, which covers existing 'dma_map_resource' flow in the
common paths, what in turn lets to use recently introduced
dma_iova_link() API to map PCI P2P MMIO without creating struct page
Developped by Leon Romanovsky and Jason Gunthorpe
- Minor clean-up by Petr Tesarik and Qianfeng Rong
* tag 'dma-mapping-6.18-2025-09-30' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
kmsan: fix missed kmsan_handle_dma() signature conversion
mm/hmm: properly take MMIO path
mm/hmm: migrate to physical address-based DMA mapping API
dma-mapping: export new dma_*map_phys() interface
xen: swiotlb: Open code map_resource callback
dma-mapping: implement DMA_ATTR_MMIO for dma_(un)map_page_attrs()
kmsan: convert kmsan_handle_dma to use physical addresses
dma-mapping: convert dma_direct_*map_page to be phys_addr_t based
iommu/dma: implement DMA_ATTR_MMIO for iommu_dma_(un)map_phys()
iommu/dma: rename iommu_dma_*map_page to iommu_dma_*map_phys
dma-mapping: rename trace_dma_*map_page to trace_dma_*map_phys
dma-debug: refactor to use physical addresses for page mapping
iommu/dma: implement DMA_ATTR_MMIO for dma_iova_link().
dma-mapping: introduce new DMA attribute to indicate MMIO memory
swiotlb: Remove redundant __GFP_NOWARN
dma-direct: clean up the logic in __dma_direct_alloc_pages()
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- "mm, swap: improve cluster scan strategy" from Kairui Song improves
performance and reduces the failure rate of swap cluster allocation
- "support large align and nid in Rust allocators" from Vitaly Wool
permits Rust allocators to set NUMA node and large alignment when
perforning slub and vmalloc reallocs
- "mm/damon/vaddr: support stat-purpose DAMOS" from Yueyang Pan extend
DAMOS_STAT's handling of the DAMON operations sets for virtual
address spaces for ops-level DAMOS filters
- "execute PROCMAP_QUERY ioctl under per-vma lock" from Suren
Baghdasaryan reduces mmap_lock contention during reads of
/proc/pid/maps
- "mm/mincore: minor clean up for swap cache checking" from Kairui Song
performs some cleanup in the swap code
- "mm: vm_normal_page*() improvements" from David Hildenbrand provides
code cleanup in the pagemap code
- "add persistent huge zero folio support" from Pankaj Raghav provides
a block layer speedup by optionalls making the
huge_zero_pagepersistent, instead of releasing it when its refcount
falls to zero
- "kho: fixes and cleanups" from Mike Rapoport adds a few touchups to
the recently added Kexec Handover feature
- "mm: make mm->flags a bitmap and 64-bit on all arches" from Lorenzo
Stoakes turns mm_struct.flags into a bitmap. To end the constant
struggle with space shortage on 32-bit conflicting with 64-bit's
needs
- "mm/swapfile.c and swap.h cleanup" from Chris Li cleans up some swap
code
- "selftests/mm: Fix false positives and skip unsupported tests" from
Donet Tom fixes a few things in our selftests code
- "prctl: extend PR_SET_THP_DISABLE to only provide THPs when advised"
from David Hildenbrand "allows individual processes to opt-out of
THP=always into THP=madvise, without affecting other workloads on the
system".
It's a long story - the [1/N] changelog spells out the considerations
- "Add and use memdesc_flags_t" from Matthew Wilcox gets us started on
the memdesc project. Please see
https://kernelnewbies.org/MatthewWilcox/Memdescs and
https://blogs.oracle.com/linux/post/introducing-memdesc
- "Tiny optimization for large read operations" from Chi Zhiling
improves the efficiency of the pagecache read path
- "Better split_huge_page_test result check" from Zi Yan improves our
folio splitting selftest code
- "test that rmap behaves as expected" from Wei Yang adds some rmap
selftests
- "remove write_cache_pages()" from Christoph Hellwig removes that
function and converts its two remaining callers
- "selftests/mm: uffd-stress fixes" from Dev Jain fixes some UFFD
selftests issues
- "introduce kernel file mapped folios" from Boris Burkov introduces
the concept of "kernel file pages". Using these permits btrfs to
account its metadata pages to the root cgroup, rather than to the
cgroups of random inappropriate tasks
- "mm/pageblock: improve readability of some pageblock handling" from
Wei Yang provides some readability improvements to the page allocator
code
- "mm/damon: support ARM32 with LPAE" from SeongJae Park teaches DAMON
to understand arm32 highmem
- "tools: testing: Use existing atomic.h for vma/maple tests" from
Brendan Jackman performs some code cleanups and deduplication under
tools/testing/
- "maple_tree: Fix testing for 32bit compiles" from Liam Howlett fixes
a couple of 32-bit issues in tools/testing/radix-tree.c
- "kasan: unify kasan_enabled() and remove arch-specific
implementations" from Sabyrzhan Tasbolatov moves KASAN arch-specific
initialization code into a common arch-neutral implementation
- "mm: remove zpool" from Johannes Weiner removes zspool - an
indirection layer which now only redirects to a single thing
(zsmalloc)
- "mm: task_stack: Stack handling cleanups" from Pasha Tatashin makes a
couple of cleanups in the fork code
- "mm: remove nth_page()" from David Hildenbrand makes rather a lot of
adjustments at various nth_page() callsites, eventually permitting
the removal of that undesirable helper function
- "introduce kasan.write_only option in hw-tags" from Yeoreum Yun
creates a KASAN read-only mode for ARM, using that architecture's
memory tagging feature. It is felt that a read-only mode KASAN is
suitable for use in production systems rather than debug-only
- "mm: hugetlb: cleanup hugetlb folio allocation" from Kefeng Wang does
some tidying in the hugetlb folio allocation code
- "mm: establish const-correctness for pointer parameters" from Max
Kellermann makes quite a number of the MM API functions more accurate
about the constness of their arguments. This was getting in the way
of subsystems (in this case CEPH) when they attempt to improving
their own const/non-const accuracy
- "Cleanup free_pages() misuse" from Vishal Moola fixes a number of
code sites which were confused over when to use free_pages() vs
__free_pages()
- "Add Rust abstraction for Maple Trees" from Alice Ryhl makes the
mapletree code accessible to Rust. Required by nouveau and by its
forthcoming successor: the new Rust Nova driver
- "selftests/mm: split_huge_page_test: split_pte_mapped_thp
improvements" from David Hildenbrand adds a fix and some cleanups to
the thp selftesting code
- "mm, swap: introduce swap table as swap cache (phase I)" from Chris
Li and Kairui Song is the first step along the path to implementing
"swap tables" - a new approach to swap allocation and state tracking
which is expected to yield speed and space improvements. This
patchset itself yields a 5-20% performance benefit in some situations
- "Some ptdesc cleanups" from Matthew Wilcox utilizes the new memdesc
layer to clean up the ptdesc code a little
- "Fix va_high_addr_switch.sh test failure" from Chunyu Hu fixes some
issues in our 5-level pagetable selftesting code
- "Minor fixes for memory allocation profiling" from Suren Baghdasaryan
addresses a couple of minor issues in relatively new memory
allocation profiling feature
- "Small cleanups" from Matthew Wilcox has a few cleanups in
preparation for more memdesc work
- "mm/damon: add addr_unit for DAMON_LRU_SORT and DAMON_RECLAIM" from
Quanmin Yan makes some changes to DAMON in furtherance of supporting
arm highmem
- "selftests/mm: Add -Wunreachable-code and fix warnings" from Muhammad
Anjum adds that compiler check to selftests code and fixes the
fallout, by removing dead code
- "Improvements to Victim Process Thawing and OOM Reaper Traversal
Order" from zhongjinji makes a number of improvements in the OOM
killer: mainly thawing a more appropriate group of victim threads so
they can release resources
- "mm/damon: misc fixups and improvements for 6.18" from SeongJae Park
is a bunch of small and unrelated fixups for DAMON
- "mm/damon: define and use DAMON initialization check function" from
SeongJae Park implement reliability and maintainability improvements
to a recently-added bug fix
- "mm/damon/stat: expose auto-tuned intervals and non-idle ages" from
SeongJae Park provides additional transparency to userspace clients
of the DAMON_STAT information
- "Expand scope of khugepaged anonymous collapse" from Dev Jain removes
some constraints on khubepaged's collapsing of anon VMAs. It also
increases the success rate of MADV_COLLAPSE against an anon vma
- "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()"
from Lorenzo Stoakes moves us further towards removal of
file_operations.mmap(). This patchset concentrates upon clearing up
the treatment of stacked filesystems
- "mm: Improve mlock tracking for large folios" from Kiryl Shutsemau
provides some fixes and improvements to mlock's tracking of large
folios. /proc/meminfo's "Mlocked" field became more accurate
- "mm/ksm: Fix incorrect accounting of KSM counters during fork" from
Donet Tom fixes several user-visible KSM stats inaccuracies across
forks and adds selftest code to verify these counters
- "mm_slot: fix the usage of mm_slot_entry" from Wei Yang addresses
some potential but presently benign issues in KSM's mm_slot handling
* tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (372 commits)
mm: swap: check for stable address space before operating on the VMA
mm: convert folio_page() back to a macro
mm/khugepaged: use start_addr/addr for improved readability
hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list
alloc_tag: fix boot failure due to NULL pointer dereference
mm: silence data-race in update_hiwater_rss
mm/memory-failure: don't select MEMORY_ISOLATION
mm/khugepaged: remove definition of struct khugepaged_mm_slot
mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL
hugetlb: increase number of reserving hugepages via cmdline
selftests/mm: add fork inheritance test for ksm_merging_pages counter
mm/ksm: fix incorrect KSM counter handling in mm_struct during fork
drivers/base/node: fix double free in register_one_node()
mm: remove PMD alignment constraint in execmem_vmalloc()
mm/memory_hotplug: fix typo 'esecially' -> 'especially'
mm/rmap: improve mlock tracking for large folios
mm/filemap: map entire large folio faultaround
mm/fault: try to map the entire file folio in finish_fault()
mm/rmap: mlock large folios in try_to_unmap_one()
mm/rmap: fix a mlock race condition in folio_referenced_one()
...
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dma_common_contiguous_remap() is used to remap an "allocated contiguous
region". Within a single allocation, there is no need to use nth_page()
anymore.
Neither the buddy, nor hugetlb, nor CMA will hand out problematic page
ranges.
Link: https://lkml.kernel.org/r/20250901150359.867252-24-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Introduce new DMA mapping functions dma_map_phys() and dma_unmap_phys()
that operate directly on physical addresses instead of page+offset
parameters. This provides a more efficient interface for drivers that
already have physical addresses available.
The new functions are implemented as the primary mapping layer, with
the existing dma_map_page_attrs()/dma_map_resource() and
dma_unmap_page_attrs()/dma_unmap_resource() functions converted to simple
wrappers around the phys-based implementations.
In case dma_map_page_attrs(), the struct page is converted to physical
address with help of page_to_phys() function and dma_map_resource()
provides physical address as is together with addition of DMA_ATTR_MMIO
attribute.
The old page-based API is preserved in mapping.c to ensure that existing
code won't be affected by changing EXPORT_SYMBOL to EXPORT_SYMBOL_GPL
variant for dma_*map_phys().
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/54cc52af91777906bbe4a386113437ba0bcfba9c.1757423202.git.leonro@nvidia.com
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Make dma_map_page_attrs() and dma_map_page_attrs() respect
DMA_ATTR_MMIO.
DMA_ATR_MMIO makes the functions behave the same as
dma_(un)map_resource():
- No swiotlb is possible
- Legacy dma_ops arches use ops->map_resource()
- No kmsan
- No arch_dma_map_phys_direct()
The prior patches have made the internal functions called here
support DMA_ATTR_MMIO.
This is also preparation for turning dma_map_resource() into an inline
calling dma_map_phys(DMA_ATTR_MMIO) to consolidate the flows.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/3660e2c78ea409d6c483a215858fb3af52cd0ed3.1757423202.git.leonro@nvidia.com
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Convert the KMSAN DMA handling function from page-based to physical
address-based interface.
The refactoring renames kmsan_handle_dma() parameters from accepting
(struct page *page, size_t offset, size_t size) to (phys_addr_t phys,
size_t size). The existing semantics where callers are expected to
provide only kmap memory is continued here.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/3557cbaf66e935bc794f37d2b891ef75cbf2c80c.1757423202.git.leonro@nvidia.com
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Convert the DMA direct mapping functions to accept physical addresses
directly instead of page+offset parameters. The functions were already
operating on physical addresses internally, so this change eliminates
the redundant page-to-physical conversion at the API boundary.
The functions dma_direct_map_page() and dma_direct_unmap_page() are
renamed to dma_direct_map_phys() and dma_direct_unmap_phys() respectively,
with their calling convention changed from (struct page *page,
unsigned long offset) to (phys_addr_t phys).
Architecture-specific functions arch_dma_map_page_direct() and
arch_dma_unmap_page_direct() are similarly renamed to
arch_dma_map_phys_direct() and arch_dma_unmap_phys_direct().
The is_pci_p2pdma_page() checks are replaced with DMA_ATTR_MMIO checks
to allow integration with dma_direct_map_resource and dma_direct_map_phys()
is extended to support MMIO path either.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/bb15a22f76dc2e26683333ff54e789606cfbfcf0.1757423202.git.leonro@nvidia.com
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Rename the IOMMU DMA mapping functions to better reflect their actual
calling convention. The functions iommu_dma_map_page() and
iommu_dma_unmap_page() are renamed to iommu_dma_map_phys() and
iommu_dma_unmap_phys() respectively, as they already operate on physical
addresses rather than page structures.
The calling convention changes from accepting (struct page *page,
unsigned long offset) to (phys_addr_t phys), which eliminates the need
for page-to-physical address conversion within the functions. This
renaming prepares for the broader DMA API conversion from page-based
to physical address-based mapping throughout the kernel.
All callers are updated to pass physical addresses directly, including
dma_map_page_attrs(), scatterlist mapping functions, and DMA page
allocation helpers. The change simplifies the code by removing the
page_to_phys() + offset calculation that was previously done inside
the IOMMU functions.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/ed172f95f8f57782beae04f782813366894e98df.1757423202.git.leonro@nvidia.com
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As a preparation for following map_page -> map_phys API conversion,
let's rename trace_dma_*map_page() to be trace_dma_*map_phys().
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/c0c02d7d8bd4a148072d283353ba227516a76682.1757423202.git.leonro@nvidia.com
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Convert the DMA debug infrastructure from page-based to physical address-based
mapping as a preparation to rely on physical address for DMA mapping routines.
The refactoring renames debug_dma_map_page() to debug_dma_map_phys() and
changes its signature to accept a phys_addr_t parameter instead of struct page
and offset. Similarly, debug_dma_unmap_page() becomes debug_dma_unmap_phys().
A new dma_debug_phy type is introduced to distinguish physical address mappings
from other debug entry types. All callers throughout the codebase are updated
to pass physical addresses directly, eliminating the need for page-to-physical
conversion in the debug layer.
This refactoring eliminates the need to convert between page pointers and
physical addresses in the debug layer, making the code more efficient and
consistent with the DMA mapping API's physical address focus.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
[mszyprow: added a fixup]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/56d1a6769b68dfcbf8b26a75a7329aeb8e3c3b6a.1757423202.git.leonro@nvidia.com
Link: https://lore.kernel.org/all/20250910052618.GH341237@unreal/
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dma-mapping fix for Linux 6.17
- one more fix for DMA API debugging infrastructure (Baochen Qiang)
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As discussed in [1], there is no need to enforce dma mapping check on
noncoherent allocations, a simple test on the returned CPU address is
good enough.
Add a new pair of debug helpers and use them for noncoherent alloc/free
to fix this issue.
Fixes: efa70f2fdc84 ("dma-mapping: add a new dma_alloc_pages API")
Link: https://lore.kernel.org/all/ff6c1fe6-820f-4e58-8395-df06aa91706c@oss.qualcomm.com # 1
Signed-off-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250828-dma-debug-fix-noncoherent-dma-check-v1-1-76e9be0dd7fc@oss.qualcomm.com
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When CONFIG_DMA_DIRECT_REMAP is enabled, atomic pool pages are
remapped via dma_common_contiguous_remap() using the supplied
pgprot. Currently, the mapping uses
pgprot_dmacoherent(PAGE_KERNEL), which leaves the memory encrypted
on systems with memory encryption enabled (e.g., ARM CCA Realms).
This can cause the DMA layer to fail or crash when accessing the
memory, as the underlying physical pages are not configured as
expected.
Fix this by requesting a decrypted mapping in the vmap() call:
pgprot_decrypted(pgprot_dmacoherent(PAGE_KERNEL))
This ensures that atomic pool memory is consistently mapped
unencrypted.
Cc: stable@vger.kernel.org
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250811181759.998805-1-sdonthineni@nvidia.com
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Restructure the call site for dma_contiguous_early_fixup() to
where the reserved_mem nodes are being parsed from the DT so that
dma_mmu_remap[] is populated before dma_contiguous_remap() is called.
Fixes: 8a6e02d0c00e ("of: reserved_mem: Restructure how the reserved memory regions are processed")
Signed-off-by: Oreoluwa Babatunde <oreoluwa.babatunde@oss.qualcomm.com>
Tested-by: William Zhang <william.zhang@broadcom.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250806172421.2748302-1-oreoluwa.babatunde@oss.qualcomm.com
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Commit 16f5dfbc851b ("gfp: include __GFP_NOWARN in GFP_NOWAIT")
made GFP_NOWAIT implicitly include __GFP_NOWARN.
Therefore, explicit __GFP_NOWARN combined with GFP_NOWAIT
(e.g., `GFP_NOWAIT | __GFP_NOWARN`) is now redundant. Let's clean
up these redundant flags across subsystems.
No functional changes.
Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250805023222.332920-1-rongqianfeng@vivo.com
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Convert a goto-based loop to a while() loop. To allow the simplification,
return early when allocation from CMA is successful. As a bonus, this early
return avoids a repeated dma_coherent_ok() check.
No functional change.
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250710083829.1853466-1-ptesarik@suse.com
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When porting a cma related usage from x86_64 server to arm64 server,
the "cma=4G@4G" setup failed on arm64. The reason is arm64 and some
other architectures have specific physical address limit for reserved
cma area, like 4GB due to the device's need for 32 bit dma. Actually
lots of platforms of those architectures don't have this device dma
limit, but still have to obey it, and are not able to reserve a huge
cma pool.
This situation could be improved by honoring the user input cma
physical address than the arch limit. As when users specify it, they
already knows what the default is which probably can't suit them.
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250612021417.44929-1-feng.tang@linux.alibaba.com
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git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux
Pull dma-mapping updates from Marek Szyprowski:
"New two step DMA mapping API, which is is a first step to a long path
to provide alternatives to scatterlist and to remove hacks, abuses and
design mistakes related to scatterlists.
This new approach optimizes some calls to DMA-IOMMU layer and cache
maintenance by batching them, reduces memory usage as it is no need to
store mapped DMA addresses to unmap them, and reduces some function
call overhead. It is a combination effort of many people, lead and
developed by Christoph Hellwig and Leon Romanovsky"
* tag 'dma-mapping-6.16-2025-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
docs: core-api: document the IOVA-based API
dma-mapping: add a dma_need_unmap helper
dma-mapping: Implement link/unlink ranges API
iommu/dma: Factor out a iommu_dma_map_swiotlb helper
dma-mapping: Provide an interface to allow allocate IOVA
iommu: add kernel-doc for iommu_unmap_fast
iommu: generalize the batched sync after map interface
dma-mapping: move the PCI P2PDMA mapping helpers to pci-p2pdma.h
PCI/P2PDMA: Refactor the p2pdma mapping helpers
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Add helper that allows a driver to skip calling dma_unmap_*
if the DMA layer can guarantee that they are no-nops.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
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To support the upcoming non-scatterlist mapping helpers, we need to go
back to have them called outside of the DMA API. Thus move them out of
dma-map-ops.h, which is only for DMA API implementations to pci-p2pdma.h,
which is for driver use.
Note that the core helper is still not exported as the mapping is
expected to be done only by very highlevel subsystem code at least for
now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
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The current scheme with a single helper to determine the P2P status
and map a scatterlist segment force users to always use the map_sg
helper to DMA map, which we're trying to get away from because they
are very cache inefficient.
Refactor the code so that there is a single helper that checks the P2P
state for a page, including the result that it is not a P2P page to
simplify the callers, and a second one to perform the address translation
for a bus mapped P2P transfer that does not depend on the scatterlist
structure.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
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When a reserved memory region described in the device tree is attached
to a device, it is expected that the device's limitations are correctly
included in that description.
However, if the device driver failed to implement DMA address masking
or addressing beyond the default 32 bits (on arm64), then bad things
could happen because the DMA address was truncated, such as playing
back audio with no actual audio coming out, or DMA overwriting random
blocks of kernel memory.
Check against the coherent DMA mask when the memory regions are attached
to the device. Give a warning when the memory region can not be covered
by the mask.
A warning instead of a hard error was chosen, because it is possible
that existing drivers could be working fine even if they forgot to
extend the coherent DMA mask.
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250421083930.374173-1-wenst@chromium.org
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lkp reported a warning about missing prototype for a recent patch.
The kernel-doc style comments are out of sync, move them to the right
function.
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Christoph Hellwig <hch@lst.de>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202504190615.g9fANxHw-lkp@intel.com/
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
[mszyprow: reformatted subject]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250422114034.3535515-1-balbirs@nvidia.com
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In the debug and resolution of an issue involving forced use of bounce
buffers, 7170130e4c72 ("x86/mm/init: Handle the special case of device
private pages in add_pages(), to not increase max_pfn and trigger
dma_addressing_limited() bounce buffers"). It would have been easier
to debug the issue if dma_addressing_limited() had debug information
about the device not being able to address all of memory and thus forcing
all accesses through a bounce buffer. Please see[2]
Implement dev_dbg to debug the potential use of bounce buffers
when we hit the condition. When swiotlb is used,
dma_addressing_limited() is used to determine the size of maximum dma
buffer size in dma_direct_max_mapping_size(). The debug prints could be
triggered in that check as well (when enabled).
Link: https://lore.kernel.org/lkml/20250401000752.249348-1-balbirs@nvidia.com/ [1]
Link: https://lore.kernel.org/lkml/20250310112206.4168-1-spasswolf@web.de/ [2]
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250414113752.3298276-1-balbirs@nvidia.com
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When building with W=1, this variable is unused for configs with
CONFIG_CMA_SIZE_SEL_PERCENTAGE=y:
kernel/dma/contiguous.c:67:26: error: 'size_bytes' defined but not used [-Werror=unused-const-variable=]
Change this to a macro to avoid the warning.
Fixes: c64be2bb1c6e ("drivers: add Contiguous Memory Allocator")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250409151557.3890443-1-arnd@kernel.org
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As discussed in [1], if 'bdr' is set once, it would never get
cleared, hence 0 is always returned.
Refactor the range check hunk into a new helper dma_find_range(),
which allows 'bdr' to be cleared in each iteration.
Link: https://lore.kernel.org/all/64931fac-085b-4ff3-9314-84bac2fa9bdb@quicinc.com/ # [1]
Fixes: a409d9600959 ("dma-mapping: fix dma_addressing_limited() if dma_range_map can't cover all system RAM")
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Baochen Qiang <quic_bqiang@quicinc.com>
Link: https://lore.kernel.org/r/20250307030350.69144-1-quic_bqiang@quicinc.com
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
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Offset into the page should also be considered while calculating a physical
address for struct dma_debug_entry. page_to_phys() just shifts the value
PAGE_SHIFT bits to the left so offset part is zero-filled.
An example (wrong) debug assertion failure with CONFIG_DMA_API_DEBUG
enabled which is observed during systemd boot process after recent
dma-debug changes:
DMA-API: e1000 0000:00:03.0: cacheline tracking EEXIST, overlapping mappings aren't supported
WARNING: CPU: 4 PID: 941 at kernel/dma/debug.c:596 add_dma_entry
CPU: 4 UID: 0 PID: 941 Comm: ip Not tainted 6.12.0+ #288
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:add_dma_entry kernel/dma/debug.c:596
Call Trace:
<TASK>
debug_dma_map_page kernel/dma/debug.c:1236
dma_map_page_attrs kernel/dma/mapping.c:179
e1000_alloc_rx_buffers drivers/net/ethernet/intel/e1000/e1000_main.c:4616
...
Found by Linux Verification Center (linuxtesting.org).
Fixes: 9d4f645a1fd4 ("dma-debug: store a phys_addr_t in struct dma_debug_entry")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
[hch: added a little helper to clean up the code]
Signed-off-by: Christoph Hellwig <hch@lst.de>
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On RZ/Five, which is non-coherent, and uses CONFIG_DMA_GLOBAL_POOL=y:
Oops - store (or AMO) access fault [#1]
CPU: 0 UID: 0 PID: 1 Comm: swapper Not tainted 6.12.0-rc1-00015-g8a6e02d0c00e #201
Hardware name: Renesas SMARC EVK based on r9a07g043f01 (DT)
epc : __memset+0x60/0x100
ra : __dma_alloc_from_coherent+0x150/0x17a
epc : ffffffff8062d2bc ra : ffffffff80053a94 sp : ffffffc60000ba20
gp : ffffffff812e9938 tp : ffffffd601920000 t0 : ffffffc6000d0000
t1 : 0000000000000000 t2 : ffffffffe9600000 s0 : ffffffc60000baa0
s1 : ffffffc6000d0000 a0 : ffffffc6000d0000 a1 : 0000000000000000
a2 : 0000000000001000 a3 : ffffffc6000d1000 a4 : 0000000000000000
a5 : 0000000000000000 a6 : ffffffd601adacc0 a7 : ffffffd601a841a8
s2 : ffffffd6018573c0 s3 : 0000000000001000 s4 : ffffffd6019541e0
s5 : 0000000200000022 s6 : ffffffd6018f8410 s7 : ffffffd6018573e8
s8 : 0000000000000001 s9 : 0000000000000001 s10: 0000000000000010
s11: 0000000000000000 t3 : 0000000000000000 t4 : ffffffffdefe62d1
t5 : 000000001cd6a3a9 t6 : ffffffd601b2aad6
status: 0000000200000120 badaddr: ffffffc6000d0000 cause: 0000000000000007
[<ffffffff8062d2bc>] __memset+0x60/0x100
[<ffffffff80053e1a>] dma_alloc_from_global_coherent+0x1c/0x28
[<ffffffff80053056>] dma_direct_alloc+0x98/0x112
[<ffffffff8005238c>] dma_alloc_attrs+0x78/0x86
[<ffffffff8035fdb4>] rz_dmac_probe+0x3f6/0x50a
[<ffffffff803a0694>] platform_probe+0x4c/0x8a
If CONFIG_DMA_GLOBAL_POOL=y, the reserved_mem structure passed to
rmem_dma_setup() is saved for later use, by saving the passed pointer.
However, when dma_init_reserved_memory() is called later, the pointer
has become stale, causing a crash.
E.g. in the RZ/Five case, the referenced memory now contains the
reserved_mem structure for the "mmode_resv0@30000" node (with base
0x30000 and size 0x10000), instead of the correct "pma_resv0@58000000"
node (with base 0x58000000 and size 0x8000000).
Fix this by saving the needed reserved_mem structure's contents instead.
Fixes: 8a6e02d0c00e7b62 ("of: reserved_mem: Restructure how the reserved memory regions are processed")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Oreoluwa Babatunde <quic_obabatun@quicinc.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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trace_dma_alloc_sgt_err was called with the dir and flags arguments
swapped. Fix this.
Fixes: 68b6dbf1f441 ("dma-mapping: trace more error paths")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202410302243.1wnTlPk3-lkp@intel.com/
Signed-off-by: Christoph Hellwig <hch@lst.de>
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It can be surprising to the user if DMA functions are only traced on
success. On failure, it can be unclear what the source of the problem
is. Fix this by tracing all functions even when they fail. Cases where
we BUG/WARN are skipped, since those should be sufficiently noisy
already.
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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In some cases, we use trace_dma_map to trace dma_alloc* functions. This
generally follows dma_debug. However, this does not record all of the
relevant information for allocations, such as GFP flags. Create new
dma_alloc tracepoints for these functions. Note that while
dma_alloc_noncontiguous may allocate discontiguous pages (from the CPU's
point of view), the device will only see one contiguous mapping.
Therefore, we just need to trace dma_addr and size.
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
|
In preparation for using these tracepoints in a few more places, trace
the DMA direction as well. For coherent allocations this is always
bidirectional.
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
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The scatterlist validity checks are pretty simple and cheap, perform them
unconditionally.
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
|
dma-debug goes to great length to split incoming physical addresses into
a PFN and offset to store them in struct dma_debug_entry, just to
recombine those for all meaningful uses. Just store a phys_addr_t
instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
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|
radix_lock() shouldn't be held while holding dma_hash_entry[idx].lock
otherwise, there's a possible deadlock scenario when
dma debug API is called holding rq_lock():
CPU0 CPU1 CPU2
dma_free_attrs()
check_unmap() add_dma_entry() __schedule() //out
(A) rq_lock()
get_hash_bucket()
(A) dma_entry_hash
check_sync()
(A) radix_lock() (W) dma_entry_hash
dma_entry_free()
(W) radix_lock()
// CPU2's one
(W) rq_lock()
CPU1 situation can happen when it extending radix tree and
it tries to wake up kswapd via wake_all_kswapd().
CPU2 situation can happen while perf_event_task_sched_out()
(i.e. dma sync operation is called while deleting perf_event using
etm and etr tmc which are Arm Coresight hwtracing driver backends).
To remove this possible situation, call dma_entry_free() after
put_hash_bucket() in check_unmap().
Reported-by: Denis Nikitin <denik@chromium.org>
Closes: https://lists.linaro.org/archives/list/coresight@lists.linaro.org/thread/2WMS7BBSF5OZYB63VT44U5YWLFP5HL6U/#RWM6MLQX5ANBTEQ2PRM7OXCBGCE6NPWU
Signed-off-by: Levi Yun <yeoreum.yun@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
|
While using the IOMMU DMA path, the dma_addressing_limited() function
checks ops struct which doesn't exist in the IOMMU case. This causes
to the kernel panic while loading ADMGPU driver.
BUG: kernel NULL pointer dereference, address: 00000000000000a0
PGD 0 P4D 0
Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 10 UID: 0 PID: 611 Comm: (udev-worker) Tainted: G T 6.11.0-clang-07154-g726e2d0cf2bb #257
Tainted: [T]=RANDSTRUCT
Hardware name: ASUS System Product Name/ROG STRIX Z690-G GAMING WIFI, BIOS 3701 07/03/2024
RIP: 0010:dma_addressing_limited+0x53/0xa0
Code: 8b 93 48 02 00 00 48 39 d1 49 89 d6 4c 0f 42 f1 48 85 d2 4c 0f 44 f1 f6 83 fc 02 00 00 40 75 0a 48 89 df e8 1f 09 00 00 eb 24 <4c> 8b 1c 25 a0 00 00 00 4d 85 db 74 17 48 89 df 41 ba |
