VM_MIXEDMAP is used by dax to direct mm paths like vm_normal_page() that
the memory page it is dealing with is not typical memory from the linear
map. The get_user_pages_fast() path, since it does not resolve the vma,
is already using {pte,pmd}_devmap() as a stand-in for VM_MIXEDMAP, so we
use that as a VM_MIXEDMAP replacement in some locations. In the cases
where there is no pte to consult we fallback to using vma_is_dax() to
detect the VM_MIXEDMAP special case.Now that we always have pages for DAX we can stop setting VM_MIXEDMAP. This also means we no longer need to worry about safely manipulating vm_flags in a future where we support dynamically changing the dax mode of a file. Cc: Jan Kara <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Jeff Moyer <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Ross Zwisler <[email protected]> Cc: "Kirill A. Shutemov" <[email protected]> Signed-off-by: Dan Williams <[email protected]> --- drivers/dax/device.c | 2 +- fs/ext2/file.c | 1 - fs/ext4/file.c | 2 +- fs/xfs/xfs_file.c | 2 +- mm/huge_memory.c | 8 ++++---- mm/ksm.c | 3 +++ mm/madvise.c | 2 +- mm/memory.c | 20 ++++++++++++++++++-- mm/migrate.c | 3 ++- mm/mlock.c | 3 ++- mm/mmap.c | 3 ++- 11 files changed, 35 insertions(+), 14 deletions(-) diff --git a/drivers/dax/device.c b/drivers/dax/device.c index e9f3b3e4bbf4..ed79d006026e 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -450,7 +450,7 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma) return rc; vma->vm_ops = &dax_vm_ops; - vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; + vma->vm_flags |= VM_HUGEPAGE; return 0; } diff --git a/fs/ext2/file.c b/fs/ext2/file.c index ff3a3636a5ca..70657e8550ed 100644 --- a/fs/ext2/file.c +++ b/fs/ext2/file.c @@ -125,7 +125,6 @@ static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) file_accessed(file); vma->vm_ops = &ext2_dax_vm_ops; - vma->vm_flags |= VM_MIXEDMAP; return 0; } #else diff --git a/fs/ext4/file.c b/fs/ext4/file.c index b1da660ac3bc..0cc9d205bd96 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -352,7 +352,7 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma) file_accessed(file); if (IS_DAX(file_inode(file))) { vma->vm_ops = &ext4_dax_vm_ops; - vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; + vma->vm_flags |= VM_HUGEPAGE; } else { vma->vm_ops = &ext4_file_vm_ops; } diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index ebdd0bd2b261..dece8fe937f5 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1131,7 +1131,7 @@ xfs_file_mmap( file_accessed(filp); vma->vm_ops = &xfs_file_vm_ops; if (IS_DAX(file_inode(filp))) - vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; + vma->vm_flags |= VM_HUGEPAGE; return 0; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 269b5df58543..c69d30e27fd9 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -765,11 +765,11 @@ int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, * but we need to be consistent with PTEs and architectures that * can't support a 'special' bit. */ - BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); + BUG_ON(!((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) + || pfn_t_devmap(pfn))); BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == (VM_PFNMAP|VM_MIXEDMAP)); BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); - BUG_ON(!pfn_t_devmap(pfn)); if (addr < vma->vm_start || addr >= vma->vm_end) return VM_FAULT_SIGBUS; @@ -824,11 +824,11 @@ int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, * but we need to be consistent with PTEs and architectures that * can't support a 'special' bit. */ - BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); + BUG_ON(!((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) + || pfn_t_devmap(pfn))); BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == (VM_PFNMAP|VM_MIXEDMAP)); BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); - BUG_ON(!pfn_t_devmap(pfn)); if (addr < vma->vm_start || addr >= vma->vm_end) return VM_FAULT_SIGBUS; diff --git a/mm/ksm.c b/mm/ksm.c index 15dd7415f7b3..787dfe4f3d44 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2358,6 +2358,9 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start, VM_HUGETLB | VM_MIXEDMAP)) return 0; /* just ignore the advice */ + if (vma_is_dax(vma)) + return 0; + #ifdef VM_SAO if (*vm_flags & VM_SAO) return 0; diff --git a/mm/madvise.c b/mm/madvise.c index 21261ff0466f..40344d43e565 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -95,7 +95,7 @@ static long madvise_behavior(struct vm_area_struct *vma, new_flags |= VM_DONTDUMP; break; case MADV_DODUMP: - if (new_flags & VM_SPECIAL) { + if (vma_is_dax(vma) || (new_flags & VM_SPECIAL)) { error = -EINVAL; goto out; } diff --git a/mm/memory.c b/mm/memory.c index ec4e15494901..771acaf54fe6 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -830,6 +830,8 @@ struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr, return vma->vm_ops->find_special_page(vma, addr); if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) return NULL; + if (pte_devmap(pte)) + return NULL; if (is_zero_pfn(pfn)) return NULL; @@ -917,6 +919,8 @@ struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, } } + if (pmd_devmap(pmd)) + return NULL; if (is_zero_pfn(pfn)) return NULL; if (unlikely(pfn > highest_memmap_pfn)) @@ -1227,7 +1231,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, * efficient than faulting. */ if (!(vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) && - !vma->anon_vma) + !vma->anon_vma && !vma_is_dax(vma)) return 0; if (is_vm_hugetlb_page(vma)) @@ -1896,12 +1900,24 @@ int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, } EXPORT_SYMBOL(vm_insert_pfn_prot); +static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) +{ + /* these checks mirror the abort conditions in vm_normal_page */ + if (vma->vm_flags & VM_MIXEDMAP) + return true; + if (pfn_t_devmap(pfn)) + return true; + if (is_zero_pfn(pfn_t_to_pfn(pfn))) + return true; + return false; +} + static int __vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, pfn_t pfn, bool mkwrite) { pgprot_t pgprot = vma->vm_page_prot; - BUG_ON(!(vma->vm_flags & VM_MIXEDMAP)); + BUG_ON(!vm_mixed_ok(vma, pfn)); if (addr < vma->vm_start || addr >= vma->vm_end) return -EFAULT; diff --git a/mm/migrate.c b/mm/migrate.c index 6954c1435833..179a84a311f6 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2927,7 +2927,8 @@ int migrate_vma(const struct migrate_vma_ops *ops, /* Sanity check the arguments */ start &= PAGE_MASK; end &= PAGE_MASK; - if (!vma || is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) + if (!vma || is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL) + || vma_is_dax(dma)) return -EINVAL; if (start < vma->vm_start || start >= vma->vm_end) return -EINVAL; diff --git a/mm/mlock.c b/mm/mlock.c index dfc6f1912176..4d009350893f 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -520,7 +520,8 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, vm_flags_t old_flags = vma->vm_flags; if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) || - is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm)) + is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm) || + vma_is_dax(vma)) /* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */ goto out; diff --git a/mm/mmap.c b/mm/mmap.c index 680506faceae..2f3971a051c6 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1723,7 +1723,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); if (vm_flags & VM_LOCKED) { if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || - vma == get_gate_vma(current->mm))) + vma == get_gate_vma(current->mm) || + vma_is_dax(vma))) mm->locked_vm += (len >> PAGE_SHIFT); else vma->vm_flags &= VM_LOCKED_CLEAR_MASK; _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
