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coresight: Handle build path error

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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>
(cherry picked from commit 5014e904681ddbdf663bb20f134eb053ddccb181)
This commit is contained in:
Suzuki K Poulose 2016-05-06 15:35:50 +01:00 • committed by Mathieu Poirier
parent 04874216ce
commit 288bbf9d8d
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;
}