[PATCH 4.19 80/96] nfit/ars: Avoid stale ARS results

Greg Kroah-Hartman
2019-04-24T17:32:40Z

commit 78153dd45e7e0596ba32b15d02bda08e1513111e upstream.

Gate ARS result consumption on whether the OS issued start-ARS since the
previous consumption. The BIOS may only clear its result buffers after a
successful start-ARS.

Fixes: 0caeef63e6d2 ("libnvdimm: Add a poison list and export badblocks")
Cc: <stable@vger.kernel.org>
Reported-by: Krzysztof Rusocki <krzysztof.rusocki@intel.com>
Reported-by: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/acpi/nfit/core.c | 17 ++++++++++++++++-
drivers/acpi/nfit/nfit.h | 1 +
2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 4b489d14a680..925dbc751322 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2540,7 +2540,10 @@ static int ars_start(struct acpi_nfit_desc *acpi_desc,

if (rc < 0)
return rc;
- return cmd_rc;
+ if (cmd_rc < 0)
+ return cmd_rc;
+ set_bit(ARS_VALID, &acpi_desc->scrub_flags);
+ return 0;
}

static int ars_continue(struct acpi_nfit_desc *acpi_desc)
@@ -2633,6 +2636,17 @@ static int ars_status_process_records(struct acpi_nfit_desc *acpi_desc)
*/
if (ars_status->out_length < 44)
return 0;
+
+ /*
+ * Ignore potentially stale results that are only refreshed
+ * after a start-ARS event.
+ */
+ if (!test_and_clear_bit(ARS_VALID, &acpi_desc->scrub_flags)) {
+ dev_dbg(acpi_desc->dev, "skip %d stale records\n",
+ ars_status->num_records);
+ return 0;
+ }
+
for (i = 0; i < ars_status->num_records; i++) {
/* only process full records */
if (ars_status->out_length
@@ -3117,6 +3131,7 @@ static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
struct nfit_spa *nfit_spa;
int rc;

+ set_bit(ARS_VALID, &acpi_desc->scrub_flags);
list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
switch (nfit_spa_type(nfit_spa->spa)) {
case NFIT_SPA_VOLATILE:
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index b5fd3522abc7..68848fc4b7c9 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -184,6 +184,7 @@ struct nfit_mem {
enum scrub_flags {
ARS_BUSY,
ARS_CANCEL,
+ ARS_VALID,
ARS_POLL,
};

--
2.19.1