Re: [PATCH v1 5/5] coresight: Refine error handling for device registration

On 12/05/2025 16:41, Leo Yan wrote:

When error happens in a device registration, the coresight_unregister() function is invoked for cleanup. coresight_unregister() includes the complete flow for unregisteration a CoreSight device, it causes redundant operations for some errors.

This commit changes to invoke more specific functions for cleanup resources for each error. This can allow the cleanup flow in better granularity.

As a result, the local "registered" variable is not used anymore, remove it.

Signed-off-by: Leo Yan leo.yan@arm.com

drivers/hwtracing/coresight/coresight-core.c | 26 ++++++++------------ 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index 4fc82206b326..1eb4f6f0fe40 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -1297,7 +1297,6 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) { int ret; struct coresight_device *csdev;

• bool registered = false;

csdev = kzalloc(sizeof(*csdev), GFP_KERNEL); if (!csdev) { @@ -1362,27 +1361,23 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) { ret = etm_perf_add_symlink_sink(csdev);

• if (ret) {
  

• 	device_unregister(&csdev->dev);
  

• if (ret)
  /*
   * As with the above, all resources are free'd
   * explicitly via coresight_device_release() triggered
   * from put_device(), which is in turn called from
   * function device_unregister().
   */
  

• 	goto out_unlock;
  

• }
  

• 	goto out_unregister_device;
  

  }

• /* Device is now registered */
• registered = true;

ret = coresight_create_conns_sysfs_group(csdev); if (ret)

• goto out_unlock;
  

• goto out_del_symlink_sink;
  

ret = coresight_fixup_orphan_conns(csdev); if (ret)

• goto out_unlock;
  

• goto out_remove_conns;
  

mutex_unlock(&coresight_mutex); @@ -1390,15 +1385,14 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) cti_assoc_ops->add(csdev); return csdev; +out_remove_conns:

• coresight_remove_conns_sysfs_group(csdev);

+out_del_symlink_sink:

• etm_perf_del_symlink_sink(csdev);

+out_unregister_device:

• device_unregister(&csdev->dev);

Is there any reason why we can't use the coresigh_unregister() ? I see the mutex_lock() needs to be released before calling it. But otherwise all of the above could be done from there ?

Also, again, after device_unregister(), we are not allowed to touch csdev. Another reason why the release_platform_data below is a problem.

Suzuki

out_unlock: mutex_unlock(&coresight_mutex);

• /* Unregister the device if needed */
• if (registered) {

• coresight_unregister(csdev);
  

• return ERR_PTR(ret);
  

• }
• err_out: /* Cleanup the connection information */ coresight_release_platform_data(NULL, csdev->dev.parent, desc->pdata);