MEMORY_DEVICE_FS_DAX relies on typical page semantics whereby ->mapping is only ever cleared by truncation, not final put.
Without this fix dax pages may forget their mapping association at the end of every page pin event. Move this atypical behavior that HMM wants into the HMM ->page_free() callback. Cc: <[email protected]> Cc: Jan Kara <[email protected]> Cc: Jérôme Glisse <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Ross Zwisler <[email protected]> Fixes: d2c997c0f145 ("fs, dax: use page->mapping...") Signed-off-by: Dan Williams <[email protected]> --- kernel/memremap.c | 1 - mm/hmm.c | 2 ++ 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/memremap.c b/kernel/memremap.c index 5857267a4af5..62603634a1d2 100644 --- a/kernel/memremap.c +++ b/kernel/memremap.c @@ -339,7 +339,6 @@ void __put_devmap_managed_page(struct page *page) __ClearPageActive(page); __ClearPageWaiters(page); - page->mapping = NULL; mem_cgroup_uncharge(page); page->pgmap->page_free(page, page->pgmap->data); diff --git a/mm/hmm.c b/mm/hmm.c index de7b6bf77201..f9d1d89dec4d 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -963,6 +963,8 @@ static void hmm_devmem_free(struct page *page, void *data) { struct hmm_devmem *devmem = data; + page->mapping = NULL; + devmem->ops->free(devmem, page); } _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
