From: Dan Williams <dan.j.williams@intel.com>
Date: Mon, 2 Apr 2018 23:40:04 +0000 (-0700)
Subject: nfit, address-range-scrub: fix scrub in-progress reporting
X-Git-Tag: v4.9.96~49
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1c72e231eb06499e376842defa03e1e295d63ba0;p=platform%2Fkernel%2Flinux-amlogic.git

nfit, address-range-scrub: fix scrub in-progress reporting

commit 78727137fdf49edf9f731bde79d7189067b4047a upstream.

There is a small window whereby ARS scan requests can schedule work that
userspace will miss when polling scrub_show. Hold the init_mutex lock
over calls to report the status to close this potential escape. Also,
make sure that requests to cancel the ARS workqueue are treated as an
idle event.

Cc: <stable@vger.kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Fixes: 37b137ff8c83 ("nfit, libnvdimm: allow an ARS scrub...")
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 37032545c58e..3874eec972cd 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -967,8 +967,11 @@ static ssize_t scrub_show(struct device *dev,
 	if (nd_desc) {
 		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
 
+		mutex_lock(&acpi_desc->init_mutex);
 		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
-				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+				work_busy(&acpi_desc->work)
+				&& !acpi_desc->cancel ? "+\n" : "\n");
+		mutex_unlock(&acpi_desc->init_mutex);
 	}
 	device_unlock(dev);
 	return rc;