[PATCH 00/21] mm: Add vma_lookup()

Liam Howlett
2021-05-10T17:02:22Z

Many places in the kernel use find_vma() to get a vma and then check the
start address of the vma to ensure the next vma was not returned.

Other places use the find_vma_intersection() call with add, addr + 1 as
the range; looking for just the vma at a specific address.

The third use of find_vma() is by developers who do not know that the
function starts searching at the provided address upwards for the next
vma. This results in a bug that is often overlooked for a long time.

Adding the new vma_lookup() function will allow for cleaner code by
removing the find_vma() calls which check limits, making
find_vma_intersection() calls of a single address to be shorter, and
potentially reduce the incorrect uses of find_vma().

This patch set was originally part of the maple tree patch set.
Changes since being broken out on its own:
- Changed initial implementation of vma_lookup() to use find_vma() as requested
by Michel Lespinasse.
- Updated commit comments to be more descriptive

These patches are based on next-20210506

Liam R. Howlett (22):
mm: Add vma_lookup()
drm/i915/selftests: Use vma_lookup() in __igt_mmap()
arch/arc/kernel/troubleshoot: use vma_lookup() instead of find_vma()
arch/arm64/kvm: Use vma_lookup() instead of find_vma_intersection()
arch/powerpc/kvm/book3s_hv_uvmem: Use vma_lookup() instead of
find_vma_intersection()
arch/powerpc/kvm/book3s: Use vma_lookup() in
kvmppc_hv_setup_htab_rma()
arch/mips/kernel/traps: Use vma_lookup() instead of find_vma()
arch/m68k/kernel/sys_m68k: Use vma_lookup() in sys_cacheflush()
x86/sgx: Use vma_lookup() in sgx_encl_find()
virt/kvm: Use vma_lookup() instead of find_vma_intersection()
vfio: Use vma_lookup() instead of find_vma_intersection()
net/ipv5/tcp: Use vma_lookup() in tcp_zerocopy_receive()
drm/amdgpu: Use vma_lookup() in amdgpu_ttm_tt_get_user_pages()
media: videobuf2: Use vma_lookup() in get_vaddr_frames()
misc/sgi-gru/grufault: Use vma_lookup() in gru_find_vma()
kernel/events/uprobes: Use vma_lookup() in find_active_uprobe()
lib/test_hmm: Use vma_lookup() in dmirror_migrate()
mm/ksm: Use vma_lookup() in find_mergeable_vma()
mm/migrate: Use vma_lookup() in do_pages_stat_array()
mm/mremap: Use vma_lookup() in vma_to_resize()
mm/memory.c: Use vma_lookup() in __access_remote_vm()
mm/mempolicy: Use vma_lookup() in __access_remote_vm()

arch/arc/kernel/troubleshoot.c | 8 ++++----
arch/arm64/kvm/mmu.c | 2 +-
arch/m68k/kernel/sys_m68k.c | 4 ++--
arch/mips/kernel/traps.c | 4 +---
arch/powerpc/kvm/book3s_hv.c | 4 ++--
arch/powerpc/kvm/book3s_hv_uvmem.c | 2 +-
arch/x86/kernel/cpu/sgx/encl.h | 4 ++--
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 4 ++--
.../gpu/drm/i915/gem/selftests/i915_gem_mman.c | 2 +-
drivers/media/common/videobuf2/frame_vector.c | 2 +-
drivers/misc/sgi-gru/grufault.c | 4 ++--
drivers/vfio/vfio_iommu_type1.c | 2 +-
include/linux/mm.h | 18 ++++++++++++++++++
kernel/events/uprobes.c | 4 ++--
lib/test_hmm.c | 5 ++---
mm/ksm.c | 6 ++----
mm/memory.c | 4 ++--
mm/mempolicy.c | 2 +-
mm/migrate.c | 4 ++--
mm/mremap.c | 4 ++--
net/ipv4/tcp.c | 4 ++--
virt/kvm/kvm_main.c | 2 +-
22 files changed, 54 insertions(+), 41 deletions(-)

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2.30.2