Commit 5014e904 authored May 06, 2016 by Suzuki K Poulose Committed by Greg Kroah-Hartman Jun 16, 2016

coresight: Handle build path error



Enabling a component via sysfs (echo 1 > enable_source), would
trigger building a path from the enabled sources to the sink.
If there is an error in the process (e.g, sink not enabled or
the device (CPU corresponding to ETM) is not online), we never report
failure, except for leaving a message in the dmesg.

Do proper error checking for the build path and return the error.

Before:
 $ echo 0 > /sys/devices/system/cpu/cpu2/online
 $ echo 1 > /sys/devices/cs_etm/cpu2/enable_source
 $ echo $?
 0

After:
 $ echo 0 > /sys/devices/system/cpu/cpu2/online
 $ echo 1 > /sys/devices/cs_etm/cpu2/enable_source
 -bash: echo: write error: No such device or address

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

parent f3b8172f

drivers/hwtracing/coresight/coresight.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -425,6 +425,7 @@ static int _coresight_build_path(struct coresight_device *csdev,
		struct list_head coresight_build_path(struct coresight_device csdev)
		{
		struct list_head *path;
		int rc;

		path = kzalloc(sizeof(struct list_head), GFP_KERNEL);
		if (!path)
		@@ -432,9 +433,10 @@ struct list_head coresight_build_path(struct coresight_device csdev)

		INIT_LIST_HEAD(path);

		if (_coresight_build_path(csdev, path)) {
		rc = _coresight_build_path(csdev, path);
		if (rc) {
		kfree(path);
		path = NULL;
		return ERR_PTR(rc);
		}

		return path;
		@@ -507,8 +509,9 @@ int coresight_enable(struct coresight_device *csdev)
		goto out;

		path = coresight_build_path(csdev);
		if (!path) {
		if (IS_ERR(path)) {
		pr_err("building path(s) failed\n");
		ret = PTR_ERR(path);
		goto out;
		}