dax: re-enable dax pmd mappings
Now that the get_user_pages() path knows how to handle dax-pmd mappings,
remove the protections that disabled dax-pmd support.
Tests available from github.com/pmem/ndctl:
make TESTS="lib/test-dax.sh lib/test-mmap.sh" check
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/dax.c b/fs/dax.c
index e1f251d..7af8797 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -592,7 +592,7 @@
sector_t block;
int result = 0;
- /* dax pmd mappings are broken wrt gup and fork */
+ /* dax pmd mappings require pfn_t_devmap() */
if (!IS_ENABLED(CONFIG_FS_DAX_PMD))
return VM_FAULT_FALLBACK;
@@ -717,11 +717,7 @@
goto fallback;
}
- /*
- * TODO: teach vmf_insert_pfn_pmd() to support
- * 'pte_special' for pmds
- */
- if (pfn_t_has_page(dax.pfn)) {
+ if (!pfn_t_devmap(dax.pfn)) {
dax_unmap_atomic(bdev, &dax);
dax_pmd_dbg(&bh, address, "pfn not in memmap");
goto fallback;