pmem_mkpage_present() is called after persistent-memory poison has been cleared. It only needs to clear PG_hwpoison and undo the MCE nospec state for PFNs that are still marked poisoned.
For clean PFNs, test_and_clear_pmem_poison() has no semantic effect, but it still performs an atomic clear operation against struct page flags. That is unnecessary today and conflicts with the FS-DAX vmemmap optimization added later in the series, where clean PFNs may be backed by shared read-only metadata. Check PageHWPoison() first so only poisoned PFNs update the page state. Poison recovery keeps the same behavior, while clean PFNs no longer require writable per-PFN metadata. Signed-off-by: Muchun Song <[email protected]> --- drivers/nvdimm/pmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 30a51c365ce8..b14f75daeda7 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -80,7 +80,7 @@ static void pmem_mkpage_present(struct pmem_device *pmem, phys_addr_t offset, * here since we're in the driver I/O path and * outstanding I/O requests pin the dev_pagemap. */ - if (test_and_clear_pmem_poison(page)) + if (PageHWPoison(page) && test_and_clear_pmem_poison(page)) clear_mce_nospec(pfn); } } -- 2.54.0
