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From fe470f5f7f684ed15bc49b6183a64237547910ff Mon Sep 17 00:00:00 2001
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: Wed, 11 Jul 2018 13:40:28 -0600
Subject: [PATCH] coresight: Handle errors in finding input/output ports
Git-commit: fe470f5f7f684ed15bc49b6183a64237547910ff
Patch-mainline: v4.19-rc1
References: bsc#1051510

If we fail to find the input / output port for a LINK component
while enabling a path, we should fail gracefully rather than
assuming port "0".

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/hwtracing/coresight/coresight.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 4969b329511c..7f2b478a048f 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -107,7 +107,7 @@ static int coresight_find_link_inport(struct coresight_device *csdev,
 	dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s\n",
 		dev_name(&parent->dev), dev_name(&csdev->dev));
 
-	return 0;
+	return -ENODEV;
 }
 
 static int coresight_find_link_outport(struct coresight_device *csdev,
@@ -125,7 +125,7 @@ static int coresight_find_link_outport(struct coresight_device *csdev,
 	dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s\n",
 		dev_name(&csdev->dev), dev_name(&child->dev));
 
-	return 0;
+	return -ENODEV;
 }
 
 static int coresight_enable_sink(struct coresight_device *csdev, u32 mode)
@@ -178,6 +178,9 @@ static int coresight_enable_link(struct coresight_device *csdev,
 	else
 		refport = 0;
 
+	if (refport < 0)
+		return refport;
+
 	if (atomic_inc_return(&csdev->refcnt[refport]) == 1) {
 		if (link_ops(csdev)->enable) {
 			ret = link_ops(csdev)->enable(csdev, inport, outport);
-- 
2.18.0