[PATCH v2 01/10] coresight: Document error handling in coresight_register
From: suzuki.poulose@arm.com (Suzuki K Poulose)
Date: 2018-07-19 10:55:44
Also in:
linux-devicetree, lkml
Subsystem:
arm/coresight framework and drivers, hardware tracing facilities, the rest · Maintainers:
Suzuki K Poulose, Alexander Shishkin, Linus Torvalds
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 <redacted>
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