From: Dave Jiang <dave.jiang@intel.com>
Date: Fri, 27 Jul 2018 09:04:17 -0700
Subject: acpi/nfit: queue issuing of ars when an uc error notification comes in
Git-commit: cc3d3458d46f702b1d118fca8647dc9157887d9b
Patch-mainline: v4.19-rc1
References: FATE#326060

When the ACPI UC error notifier gets called and ARS_REQ bit is set
with the passed in flag, we can receive -EBUSY if ARS_REQ bit is already
set for the nfit_spa->ars_state. When that happens, the ARS request is
dropped. That can potentially cause us to miss the unreported errors that
the on going ARS request does not receive. Add an ARS_REQ_REDO state that
will request short ARS upon ARS completion to grab any errors we missed.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/acpi/nfit/core.c | 12 +++++++++---
 drivers/acpi/nfit/nfit.h |  1 +
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 2be8373153ed..31f6325ab3b5 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2567,7 +2567,12 @@ static void ars_complete(struct acpi_nfit_desc *acpi_desc,
 			test_bit(ARS_SHORT, &nfit_spa->ars_state)
 			? "short" : "long");
 	clear_bit(ARS_SHORT, &nfit_spa->ars_state);
-	set_bit(ARS_DONE, &nfit_spa->ars_state);
+	if (test_and_clear_bit(ARS_REQ_REDO, &nfit_spa->ars_state)) {
+		set_bit(ARS_SHORT, &nfit_spa->ars_state);
+		set_bit(ARS_REQ, &nfit_spa->ars_state);
+		dev_dbg(dev, "ARS: processing scrub request received while in progress\n");
+	} else
+		set_bit(ARS_DONE, &nfit_spa->ars_state);
 }
 
 static int ars_status_process_records(struct acpi_nfit_desc *acpi_desc)
@@ -3242,9 +3247,10 @@ int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc, unsigned long flags)
 		if (test_bit(ARS_FAILED, &nfit_spa->ars_state))
 			continue;
 
-		if (test_and_set_bit(ARS_REQ, &nfit_spa->ars_state))
+		if (test_and_set_bit(ARS_REQ, &nfit_spa->ars_state)) {
 			busy++;
-		else {
+			set_bit(ARS_REQ_REDO, &nfit_spa->ars_state);
+		} else {
 			if (test_bit(ARS_SHORT, &flags))
 				set_bit(ARS_SHORT, &nfit_spa->ars_state);
 			scheduled++;
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index 7d15856a739f..29466961426e 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -119,6 +119,7 @@ enum nfit_dimm_notifiers {
 
 enum nfit_ars_state {
 	ARS_REQ,
+	ARS_REQ_REDO,
 	ARS_DONE,
 	ARS_SHORT,
 	ARS_FAILED,