diff mbox series

[v7,21/25] coresight: cti: increase reference count when enabling cti

Message ID 20200805025458.2978-22-tingwei@codeaurora.org (mailing list archive)
State New, archived
Headers show
Series coresight: allow to build coresight as modules | expand

Commit Message

Tingwei Zhang Aug. 5, 2020, 2:54 a.m. UTC 
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>
---
 drivers/hwtracing/coresight/coresight.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index b35f5b270a94..78439b7cd8ba 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -242,19 +242,30 @@  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;
 		}
 	}