linux.git/kernel/dma/remap.c, branch v7.0 Linux kernel source tree Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-22T01:09:51+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-02-22T00:37:42+00:00 bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43 This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21T09:02:28+00:00 Kees Cook kees@kernel.org 2026-02-21T07:49:23+00:00 69050f8d6d075dc01af7a5f2f550a8067510366f This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook <kees@kernel.org> 
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
dma-remap: drop nth_page() in dma_common_contiguous_remap() 2025-09-21T21:22:06+00:00 David Hildenbrand david@redhat.com 2025-09-01T15:03:44+00:00 a16c46c2402026162111ed9fd1fc28d25223443e 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> 
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>
dma-mapping: use bit masking to check VM_DMA_COHERENT 2024-08-22T04:15:35+00:00 Yosry Ahmed yosryahmed@google.com 2024-08-10T00:59:11+00:00 fa3c109a6d302b56437a6412c5f3044c3e12de03 In dma_common_find_pages(), area->flags are compared directly with VM_DMA_COHERENT. This works because VM_DMA_COHERENT is the only set flag. During development of a new feature (ASI [1]), a new VM flag is introduced, and that flag can be injected into VM_DMA_COHERENT mappings (among others). The presence of that flag caused dma_common_find_pages() to return NULL for VM_DMA_COHERENT addresses, leading to a lot of problems ending in crashing during boot. It took a bit of time to figure this problem out. It was a mistake to inject a VM flag to begin with, but it took a significant amount of debugging to figure out the problem. Most users of area->flags use bitmasking rather than equivalency to check for flags. Update dma_common_find_pages() and dma_common_free_remap() to do the same, which would have avoided the boot crashing. Instead, add a warning in dma_common_find_pages() if any extra VM flags are set to catch such problems more easily during development. No functional change intended. [1]https://lore.kernel.org/lkml/20240712-asi-rfc-24-v1-0-144b319a40d8@google.com/ Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Christoph Hellwig <hch@lst.de> 
In dma_common_find_pages(), area->flags are compared directly with
VM_DMA_COHERENT. This works because VM_DMA_COHERENT is the only set
flag.

During development of a new feature (ASI [1]), a new VM flag is
introduced, and that flag can be injected into VM_DMA_COHERENT mappings
(among others).  The presence of that flag caused
dma_common_find_pages() to return NULL for VM_DMA_COHERENT addresses,
leading to a lot of problems ending in crashing during boot. It took a
bit of time to figure this problem out.

It was a mistake to inject a VM flag to begin with, but it took a
significant amount of debugging to figure out the problem. Most users of
area->flags use bitmasking rather than equivalency to check for flags.
Update dma_common_find_pages() and dma_common_free_remap() to do the
same, which would have avoided the boot crashing. Instead, add a warning
in dma_common_find_pages() if any extra VM flags are set to catch such
problems more easily during development.

No functional change intended.

[1]https://lore.kernel.org/lkml/20240712-asi-rfc-24-v1-0-144b319a40d8@google.com/

Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
dma-remap: use kvmalloc_array/kvfree for larger dma memory remap 2023-06-07T13:06:28+00:00 gaoxu gaoxu2@hihonor.com 2023-06-06T12:47:37+00:00 51ff97d54f02b4444dfc42e380ac4c058e12d5dd If dma_direct_alloc() alloc memory in size of 64MB, the inner function dma_common_contiguous_remap() will allocate 128KB memory by invoking the function kmalloc_array(). and the kmalloc_array seems to fail to try to allocate 128KB mem. Call trace: [14977.928623] qcrosvm: page allocation failure: order:5, mode:0x40cc0 [14977.928638] dump_backtrace.cfi_jt+0x0/0x8 [14977.928647] dump_stack_lvl+0x80/0xb8 [14977.928652] warn_alloc+0x164/0x200 [14977.928657] __alloc_pages_slowpath+0x9f0/0xb4c [14977.928660] __alloc_pages+0x21c/0x39c [14977.928662] kmalloc_order+0x48/0x108 [14977.928666] kmalloc_order_trace+0x34/0x154 [14977.928668] __kmalloc+0x548/0x7e4 [14977.928673] dma_direct_alloc+0x11c/0x4f8 [14977.928678] dma_alloc_attrs+0xf4/0x138 [14977.928680] gh_vm_ioctl_set_fw_name+0x3c4/0x610 [gunyah] [14977.928698] gh_vm_ioctl+0x90/0x14c [gunyah] [14977.928705] __arm64_sys_ioctl+0x184/0x210 work around by doing kvmalloc_array instead. Signed-off-by: Gao Xu <gaoxu2@hihonor.com> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Christoph Hellwig <hch@lst.de> 
If dma_direct_alloc() alloc memory in size of 64MB, the inner function
dma_common_contiguous_remap() will allocate 128KB memory by invoking
the function kmalloc_array(). and the kmalloc_array seems to fail to try to
allocate 128KB mem.

Call trace:
[14977.928623] qcrosvm: page allocation failure: order:5, mode:0x40cc0
[14977.928638] dump_backtrace.cfi_jt+0x0/0x8
[14977.928647] dump_stack_lvl+0x80/0xb8
[14977.928652] warn_alloc+0x164/0x200
[14977.928657] __alloc_pages_slowpath+0x9f0/0xb4c
[14977.928660] __alloc_pages+0x21c/0x39c
[14977.928662] kmalloc_order+0x48/0x108
[14977.928666] kmalloc_order_trace+0x34/0x154
[14977.928668] __kmalloc+0x548/0x7e4
[14977.928673] dma_direct_alloc+0x11c/0x4f8
[14977.928678] dma_alloc_attrs+0xf4/0x138
[14977.928680] gh_vm_ioctl_set_fw_name+0x3c4/0x610 [gunyah]
[14977.928698] gh_vm_ioctl+0x90/0x14c [gunyah]
[14977.928705] __arm64_sys_ioctl+0x184/0x210

work around by doing kvmalloc_array instead.

Signed-off-by: Gao Xu <gaoxu2@hihonor.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
kernel/dma: remove unnecessary unmap_kernel_range 2021-04-30T18:20:40+00:00 Nicholas Piggin npiggin@gmail.com 2021-04-30T05:58:55+00:00 e82b9b3086b93857b1b46341714751b123a4d08b vunmap will remove ptes. Link: https://lkml.kernel.org/r/20210322021806.892164-3-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Cédric Le Goater <clg@kaod.org> Cc: Uladzislau Rezki <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
vunmap will remove ptes.

Link: https://lkml.kernel.org/r/20210322021806.892164-3-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Cédric Le Goater <clg@kaod.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dma-mapping: move more functions to dma-map-ops.h 2020-10-20T08:41:07+00:00 Christoph Hellwig hch@lst.de 2020-10-20T08:41:07+00:00 695cebe58dcf3d9802cdfa9c327b5c7641a5914b Due to a mismerge a bunch of prototypes that should have moved to dma-map-ops.h are still in dma-mapping.h, fix that up. Signed-off-by: Christoph Hellwig <hch@lst.de> 
Due to a mismerge a bunch of prototypes that should have moved to
dma-map-ops.h are still in dma-mapping.h, fix that up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
dma-remap: align the size in dma_common_*_remap() 2020-06-23T12:14:41+00:00 Eric Auger eric.auger@redhat.com 2020-06-23T12:07:55+00:00 8e36baf97b252cdcafa53589e8227cbb1e85f0b0 Running a guest with a virtio-iommu protecting virtio devices is broken since commit 515e5b6d90d4 ("dma-mapping: use vmap insted of reimplementing it"). Before the conversion, the size was page aligned in __get_vm_area_node(). Doing so fixes the regression. Fixes: 515e5b6d90d4 ("dma-mapping: use vmap insted of reimplementing it") Signed-off-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> 
Running a guest with a virtio-iommu protecting virtio devices
is broken since commit 515e5b6d90d4 ("dma-mapping: use vmap insted
of reimplementing it"). Before the conversion, the size was
page aligned in __get_vm_area_node(). Doing so fixes the
regression.

Fixes: 515e5b6d90d4 ("dma-mapping: use vmap insted of reimplementing it")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Merge tag 'dma-mapping-5.8' of git://git.infradead.org/users/hch/dma-mapping 2020-06-06T18:43:23+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-06-06T18:43:23+00:00 1ee18de92927f37e6948d5a6fc73cbf89f806905 Pull dma-mapping updates from Christoph Hellwig: - enhance the dma pool to allow atomic allocation on x86 with AMD SEV (David Rientjes) - two small cleanups (Jason Yan and Peter Collingbourne) * tag 'dma-mapping-5.8' of git://git.infradead.org/users/hch/dma-mapping: dma-contiguous: fix comment for dma_release_from_contiguous dma-pool: scale the default DMA coherent pool size with memory capacity x86/mm: unencrypted non-blocking DMA allocations use coherent pools dma-pool: add pool sizes to debugfs dma-direct: atomic allocations must come from atomic coherent pools dma-pool: dynamically expanding atomic pools dma-pool: add additional coherent pools to map to gfp mask dma-remap: separate DMA atomic pools from direct remap code dma-debug: make __dma_entry_alloc_check_leak() static 
Pull dma-mapping updates from Christoph Hellwig:

 - enhance the dma pool to allow atomic allocation on x86 with AMD SEV
   (David Rientjes)

 - two small cleanups (Jason Yan and Peter Collingbourne)

* tag 'dma-mapping-5.8' of git://git.infradead.org/users/hch/dma-mapping:
  dma-contiguous: fix comment for dma_release_from_contiguous
  dma-pool: scale the default DMA coherent pool size with memory capacity
  x86/mm: unencrypted non-blocking DMA allocations use coherent pools
  dma-pool: add pool sizes to debugfs
  dma-direct: atomic allocations must come from atomic coherent pools
  dma-pool: dynamically expanding atomic pools
  dma-pool: add additional coherent pools to map to gfp mask
  dma-remap: separate DMA atomic pools from direct remap code
  dma-debug: make __dma_entry_alloc_check_leak() static
dma-mapping: use vmap insted of reimplementing it 2020-06-02T17:59:10+00:00 Christoph Hellwig hch@lst.de 2020-06-02T04:50:32+00:00 515e5b6d90d410a3b0b433853c367936830a45a4 Replace the open coded instance of vmap with the actual function. In the non-contiguous (IOMMU) case this requires an extra find_vm_area, but given that this isn't a fast path function that is a small price to pay. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Airlie <airlied@linux.ie> Cc: Gao Xiang <xiang@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Michael Kelley <mikelley@microsoft.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Wei Liu <wei.liu@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Link: http://lkml.kernel.org/r/20200414131348.444715-6-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Replace the open coded instance of vmap with the actual function.  In
the non-contiguous (IOMMU) case this requires an extra find_vm_area,
but given that this isn't a fast path function that is a small price
to pay.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>