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[1] - https://lore.kernel.org/linux-mm/cover.a7cdeffaaa366a10c65e2e7544285059cc5d55a4.1736299058.git-series.apopple@nvidia.com/ [2] - https://lore.kernel.org/linux-mm/cover.a782e309b1328f961da88abddbbc48e5b4579021.1739850794.git-series.apopple@nvidia.com/ All users of dax now require a ZONE_DEVICE page which is properly refcounted. This means there is no longer any need for the PFN_DEV, PFN_MAP and PFN_SPECIAL flags. Furthermore the PFN_SG_CHAIN and PFN_SG_LAST flags never appear to have been used. It is therefore possible to remove the pfn_t type and replace any usage with raw pfns. The remaining users of PFN_DEV have simply passed this to vmf_insert_mixed() to create pte_devmap() mappings. It is unclear why this was the case but presumably to ensure vm_normal_page() does not return these pages. These users can be trivially converted to raw pfns and creating a pXX_special() mapping to ensure vm_normal_page() still doesn't return these pages. Now that there are no users of PFN_DEV we can remove the devmap page table bit and all associated functions and macros, freeing up a software page table bit. --- Cc: gerald.schaefer@linux.ibm.com Cc: dan.j.williams@intel.com Cc: jgg@ziepe.ca Cc: willy@infradead.org Cc: david@redhat.com Cc: linux-kernel@vger.kernel.org Cc: nvdimm@lists.linux.dev Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-ext4@vger.kernel.org Cc: linux-xfs@vger.kernel.org Cc: jhubbard@nvidia.com Cc: hch@lst.de Cc: zhang.lyra@gmail.com Cc: debug@rivosinc.com Cc: bjorn@kernel.org Cc: balbirs@nvidia.com Alistair Popple (12): mm: Remove PFN_MAP, PFN_SG_CHAIN and PFN_SG_LAST mm: Convert pXd_devmap checks to vma_is_dax mm/pagewalk: Skip dax pages in pagewalk mm: Convert vmf_insert_mixed() from using pte_devmap to pte_special mm: Remove remaining uses of PFN_DEV mm/gup: Remove pXX_devmap usage from get_user_pages() mm: Remove redundant pXd_devmap calls mm/khugepaged: Remove redundant pmd_devmap() check powerpc: Remove checks for devmap pages and PMDs/PUDs mm: Remove devmap related functions and page table bits mm: Remove callers of pfn_t functionality mm/memremap: Remove unused devmap_managed_key Documentation/mm/arch_pgtable_helpers.rst | 6 +- arch/arm64/Kconfig | 1 +- arch/arm64/include/asm/pgtable-prot.h | 1 +- arch/arm64/include/asm/pgtable.h | 24 +--- arch/loongarch/Kconfig | 1 +- arch/loongarch/include/asm/pgtable-bits.h | 6 +- arch/loongarch/include/asm/pgtable.h | 19 +-- arch/powerpc/Kconfig | 1 +- arch/powerpc/include/asm/book3s/64/hash-4k.h | 6 +- arch/powerpc/include/asm/book3s/64/hash-64k.h | 7 +- arch/powerpc/include/asm/book3s/64/pgtable.h | 53 +------ arch/powerpc/include/asm/book3s/64/radix.h | 14 +-- arch/powerpc/mm/book3s64/hash_hugepage.c | 2 +- arch/powerpc/mm/book3s64/hash_pgtable.c | 3 +- arch/powerpc/mm/book3s64/hugetlbpage.c | 2 +- arch/powerpc/mm/book3s64/pgtable.c | 10 +- arch/powerpc/mm/book3s64/radix_pgtable.c | 5 +- arch/powerpc/mm/pgtable.c | 2 +- arch/riscv/Kconfig | 1 +- arch/riscv/include/asm/pgtable-64.h | 20 +-- arch/riscv/include/asm/pgtable-bits.h | 1 +- arch/riscv/include/asm/pgtable.h | 17 +-- arch/x86/Kconfig | 1 +- arch/x86/include/asm/pgtable.h | 51 +------ arch/x86/include/asm/pgtable_types.h | 5 +- arch/x86/mm/pat/memtype.c | 6 +- drivers/dax/device.c | 23 +-- drivers/dax/hmem/hmem.c | 1 +- drivers/dax/kmem.c | 1 +- drivers/dax/pmem.c | 1 +- drivers/dax/super.c | 3 +- drivers/gpu/drm/exynos/exynos_drm_gem.c | 1 +- drivers/gpu/drm/gma500/fbdev.c | 3 +- drivers/gpu/drm/i915/gem/i915_gem_mman.c | 1 +- drivers/gpu/drm/msm/msm_gem.c | 1 +- drivers/gpu/drm/omapdrm/omap_gem.c | 7 +- drivers/gpu/drm/v3d/v3d_bo.c | 1 +- drivers/md/dm-linear.c | 2 +- drivers/md/dm-log-writes.c | 2 +- drivers/md/dm-stripe.c | 2 +- drivers/md/dm-target.c | 2 +- drivers/md/dm-writecache.c | 9 +- drivers/md/dm.c | 2 +- drivers/nvdimm/pmem.c | 8 +- drivers/nvdimm/pmem.h | 4 +- drivers/s390/block/dcssblk.c | 10 +- drivers/vfio/pci/vfio_pci_core.c | 7 +- fs/cramfs/inode.c | 5 +- fs/dax.c | 55 ++---- fs/ext4/file.c | 2 +- fs/fuse/dax.c | 3 +- fs/fuse/virtio_fs.c | 5 +- fs/userfaultfd.c | 2 +- fs/xfs/xfs_file.c | 2 +- include/linux/dax.h | 9 +- include/linux/device-mapper.h | 2 +- include/linux/huge_mm.h | 19 +-- include/linux/memremap.h | 11 +- include/linux/mm.h | 11 +- include/linux/pfn.h | 9 +- include/linux/pfn_t.h | 131 +--------------- include/linux/pgtable.h | 25 +--- include/trace/events/fs_dax.h | 12 +- mm/Kconfig | 4 +- mm/debug_vm_pgtable.c | 60 +------- mm/gup.c | 162 +------------------- mm/hmm.c | 12 +- mm/huge_memory.c | 98 ++--------- mm/khugepaged.c | 2 +- mm/madvise.c | 8 +- mm/mapping_dirty_helpers.c | 4 +- mm/memory.c | 64 ++------ mm/memremap.c | 28 +--- mm/migrate.c | 1 +- mm/migrate_device.c | 2 +- mm/mprotect.c | 2 +- mm/mremap.c | 5 +- mm/page_vma_mapped.c | 5 +- mm/pagewalk.c | 20 +- mm/pgtable-generic.c | 7 +- mm/userfaultfd.c | 6 +- mm/vmscan.c | 5 +- tools/testing/nvdimm/pmem-dax.c | 6 +- tools/testing/nvdimm/test/iomap.c | 11 +- 84 files changed, 216 insertions(+), 955 deletions(-) delete mode 100644 include/linux/pfn_t.h base-commit: cf42737e247a159abe9b0dc065a3ea44808a83a0