From: Tingwei Zhang <tingwei@codeaurora.org>
Date: Mon, 28 Sep 2020 10:35:08 -0600
Subject: coresight: cti: Increase reference count when enabling cti

Git-commit: f02b089e7bddd2f66e63f926960a4e384b1f436d
Patch-mainline: v5.10-rc1
References: jsc#SLE-13629,jsc#SLE-14776

CTI device is enabled when associated coresight device is enabled.
Increase the module and device reference count for CTI device
when it's enabled. This can prevent CTI device be removed or
module be unloaded when CTI device is enabled by an active trace
session.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200928163513.70169-21-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
 drivers/hwtracing/coresight/coresight.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 711beb92166a..546c97045afe 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -241,19 +241,30 @@ coresight_control_assoc_ectdev(struct coresight_device *csdev, bool enable)
 {
 	int ect_ret = 0;
 	struct coresight_device *ect_csdev = csdev->ect_dev;
+	struct module *mod;
 
 	if (!ect_csdev)
 		return 0;
 	if ((!ect_ops(ect_csdev)->enable) || (!ect_ops(ect_csdev)->disable))
 		return 0;
 
+	mod = ect_csdev->dev.parent->driver->owner;
 	if (enable) {
-		ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
-		if (!ect_ret)
-			csdev->ect_enabled = true;
+		if (try_module_get(mod)) {
+			ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
+			if (ect_ret) {
+				module_put(mod);
+			} else {
+				get_device(ect_csdev->dev.parent);
+				csdev->ect_enabled = true;
+			}
+		} else
+			ect_ret = -ENODEV;
 	} else {
 		if (csdev->ect_enabled) {
 			ect_ret = ect_ops(ect_csdev)->disable(ect_csdev);
+			put_device(ect_csdev->dev.parent);
+			module_put(mod);
 			csdev->ect_enabled = false;
 		}
 	}
-- 
2.26.2