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Commit e1fb4a08 authored by Dave Jiang's avatar Dave Jiang Committed by Linus Torvalds
Browse files

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: default avatarDave Jiang <dave.jiang@intel.com>
Acked-by: default avatarDan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e36488c8

drivers/dax/device.c

+1 −1
Original line number Diff line number Diff line
@@ -474,7 +474,7 @@ 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;

}

fs/ext2/file.c

+0 −1
Original line number Diff line number Diff line
@@ -126,7 +126,6 @@ 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

fs/ext4/file.c

+1 −1
Original line number Diff line number Diff line
@@ -374,7 +374,7 @@ 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;

	}

fs/xfs/xfs_file.c

+1 −1
Original line number Diff line number Diff line
@@ -1169,7 +1169,7 @@ 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;

}

mm/hmm.c

+4 −2
Original line number Diff line number Diff line
@@ -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;

	}