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 <dave.jiang@intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index de2f829..93e2405 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -470,7 +470,7 @@
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 047c327..28b2609 100644
--- a/fs/ext2/file.c
+++ b/fs/ext2/file.c
@@ -126,7 +126,6 @@
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 7f80233..69d65d4 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -374,7 +374,7 @@
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 a3e7767..d14d0f7 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1171,7 +1171,7 @@
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/hmm.c b/mm/hmm.c
index de7b6bf..f40e8ad 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -676,7 +676,8 @@
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 @@
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;
}
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1cd7c1a..962bedc 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -762,11 +762,11 @@
* 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 a6d43cf..9b855a8 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2430,6 +2430,9 @@
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/memory.c b/mm/memory.c
index 7206a63..98a099b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -853,6 +853,10 @@
return NULL;
}
}
+
+ if (pte_devmap(pte))
+ return NULL;
+
print_bad_pte(vma, addr, pte, NULL);
return NULL;
}
@@ -917,6 +921,8 @@
}
}
+ if (pmd_devmap(pmd))
+ return NULL;
if (is_zero_pfn(pfn))
return NULL;
if (unlikely(pfn > highest_memmap_pfn))
diff --git a/mm/migrate.c b/mm/migrate.c
index 8c0af0f..4a83268 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2951,7 +2951,8 @@
/* 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(vma))
return -EINVAL;
if (start < vma->vm_start || start >= vma->vm_end)
return -EINVAL;
diff --git a/mm/mlock.c b/mm/mlock.c
index 74e5a65..41cc47e 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -527,7 +527,8 @@
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 d1eb87e..9859cd4 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1796,11 +1796,12 @@
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)))
- mm->locked_vm += (len >> PAGE_SHIFT);
- else
+ if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) ||
+ is_vm_hugetlb_page(vma) ||
+ vma == get_gate_vma(current->mm))
vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
+ else
+ mm->locked_vm += (len >> PAGE_SHIFT);
}
if (file)
