[PATCH AUTOSEL 4.18 47/92] coresight: Handle errors in finding input/output ports

[Sasha Levin]

From: Suzuki K Poulose <suzuki.poul...@arm.com>

[ Upstream commit fe470f5f7f684ed15bc49b6183a64237547910ff ]

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.poir...@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poir...@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
---
 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 29e834aab539..b673718952f6 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -108,7 +108,7 @@ 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,
@@ -126,7 +126,7 @@ 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)
@@ -179,6 +179,9 @@ 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);
-- 
2.17.1