[PATCH] pmem: report error on clear poison failure

From: Toshi Kani
Date: Thu Oct 13 2016 - 11:58:44 EST


ACPI Clear Uncorrectable Error DSM function may fail or may be
unsupported on a platform. pmem_clear_poison() returns without
clearing badblocks in such cases, which leads to a silent data
corruption.

Change pmem_do_bvec() and pmem_clear_poison() to return -EIO
so that filesystem can log an error message.

Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
---
drivers/nvdimm/pmem.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 42b3a82..2461843 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -47,7 +47,7 @@ static struct nd_region *to_region(struct pmem_device *pmem)
return to_nd_region(to_dev(pmem)->parent);
}

-static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
+static int pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
unsigned int len)
{
struct device *dev = to_dev(pmem);
@@ -62,8 +62,12 @@ static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
__func__, (unsigned long long) sector,
cleared / 512, cleared / 512 > 1 ? "s" : "");
badblocks_clear(&pmem->bb, sector, cleared / 512);
+ } else {
+ return -EIO;
}
+
invalidate_pmem(pmem->virt_addr + offset, len);
+ return 0;
}

static void write_pmem(void *pmem_addr, struct page *page,
@@ -123,7 +127,7 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
flush_dcache_page(page);
write_pmem(pmem_addr, page, off, len);
if (unlikely(bad_pmem)) {
- pmem_clear_poison(pmem, pmem_off, len);
+ rc = pmem_clear_poison(pmem, pmem_off, len);
write_pmem(pmem_addr, page, off, len);
}
}