From e1fb4a0864958fac2fb1b23f9f4562a9f90e3e8f Mon Sep 17 00:00:00 2001 From: Dave Jiang Date: Fri, 17 Aug 2018 15:43:40 -0700 Subject: dax: remove VM_MIXEDMAP for fsdax and device dax This patch is reworked from an earlier patch that Dan has posted: https://patchwork.kernel.org/patch/10131727/ 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 have explicit driver pfn_t-flag opt-in/opt-out for get_user_pages() support 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. DAX should also now be supported with madvise_behavior(), vma_merge(), and copy_page_range(). This patch has been tested against ndctl unit test. It has also been tested against xfstests commit: 625515d using fake pmem created by memmap and no additional issues have been observed. Link: http://lkml.kernel.org/r/152847720311.55924.16999195879201817653.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang Acked-by: Dan Williams Cc: Jan Kara Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hmm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'mm/hmm.c') diff --git a/mm/hmm.c b/mm/hmm.c index de7b6bf77201..f40e8add84b5 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -676,7 +676,8 @@ int hmm_vma_get_pfns(struct hmm_range *range) return -EINVAL; /* FIXME support hugetlb fs */ - if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) { + if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL) || + vma_is_dax(vma)) { hmm_pfns_special(range); return -EINVAL; } @@ -849,7 +850,8 @@ int hmm_vma_fault(struct hmm_range *range, bool block) return -EINVAL; /* FIXME support hugetlb fs */ - if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) { + if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL) || + vma_is_dax(vma)) { hmm_pfns_special(range); return -EINVAL; } -- cgit