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Subject[PATCH v2 01/10] coresight: Document error handling in coresight_register
Date
commit 6403587a930c ("coresight: use put_device() instead of kfree()")
fixes the double freeing of resources and ensures that the device
refcount is dropped properly. Add a comment to explain this to
help the readers and prevent people trying to "unfix" it again.

While at it, rename the labels for better readability.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
Change since v1:
- Document the error handling than trying to "unfix" the
problem.
---
drivers/hwtracing/coresight/coresight.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 3e07fd3..9fd0c38 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -1006,7 +1006,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
if (!csdev) {
ret = -ENOMEM;
- goto err_kzalloc_csdev;
+ goto err_out;
}

if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
@@ -1022,7 +1022,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
if (!refcnts) {
ret = -ENOMEM;
- goto err_kzalloc_refcnts;
+ goto err_free_csdev;
}

csdev->refcnt = refcnts;
@@ -1035,7 +1035,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
if (!conns) {
ret = -ENOMEM;
- goto err_kzalloc_conns;
+ goto err_free_refcnts;
}

for (i = 0; i < csdev->nr_outport; i++) {
@@ -1062,7 +1062,11 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
ret = device_register(&csdev->dev);
if (ret) {
put_device(&csdev->dev);
- goto err_kzalloc_csdev;
+ /*
+ * All resources are free'd explicitly via
+ * coresight_device_release(), triggered from put_device().
+ */
+ goto err_out;
}

mutex_lock(&coresight_mutex);
@@ -1074,11 +1078,11 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)

return csdev;

-err_kzalloc_conns:
+err_free_refcnts:
kfree(refcnts);
-err_kzalloc_refcnts:
+err_free_csdev:
kfree(csdev);
-err_kzalloc_csdev:
+err_out:
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(coresight_register);
--
2.7.4
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