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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>
This commit is contained in:
Suzuki K Poulose 2016-05-06 15:35:50 +01:00 committed by Greg Kroah-Hartman
parent f3b8172fe1
commit 5014e90468
1 changed files with 6 additions and 3 deletions
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9
drivers/hwtracing/coresight/coresight.c
View File

@ -425,6 +425,7 @@ out:
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;
}