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path: root/drivers/hwtracing/stm/policy.c
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Diffstat (limited to 'drivers/hwtracing/stm/policy.c')
-rw-r--r--drivers/hwtracing/stm/policy.c25
1 files changed, 19 insertions, 6 deletions
diff --git a/drivers/hwtracing/stm/policy.c b/drivers/hwtracing/stm/policy.c
index 11ab6d01a..1db189657 100644
--- a/drivers/hwtracing/stm/policy.c
+++ b/drivers/hwtracing/stm/policy.c
@@ -272,13 +272,17 @@ void stp_policy_unbind(struct stp_policy *policy)
{
struct stm_device *stm = policy->stm;
+ /*
+ * stp_policy_release() will not call here if the policy is already
+ * unbound; other users should not either, as no link exists between
+ * this policy and anything else in that case
+ */
if (WARN_ON_ONCE(!policy->stm))
return;
- mutex_lock(&stm->policy_mutex);
- stm->policy = NULL;
- mutex_unlock(&stm->policy_mutex);
+ lockdep_assert_held(&stm->policy_mutex);
+ stm->policy = NULL;
policy->stm = NULL;
stm_put_device(stm);
@@ -287,8 +291,16 @@ void stp_policy_unbind(struct stp_policy *policy)
static void stp_policy_release(struct config_item *item)
{
struct stp_policy *policy = to_stp_policy(item);
+ struct stm_device *stm = policy->stm;
+ /* a policy *can* be unbound and still exist in configfs tree */
+ if (!stm)
+ return;
+
+ mutex_lock(&stm->policy_mutex);
stp_policy_unbind(policy);
+ mutex_unlock(&stm->policy_mutex);
+
kfree(policy);
}
@@ -320,10 +332,11 @@ stp_policies_make(struct config_group *group, const char *name)
/*
* node must look like <device_name>.<policy_name>, where
- * <device_name> is the name of an existing stm device and
- * <policy_name> is an arbitrary string
+ * <device_name> is the name of an existing stm device; may
+ * contain dots;
+ * <policy_name> is an arbitrary string; may not contain dots
*/
- p = strchr(devname, '.');
+ p = strrchr(devname, '.');
if (!p) {
kfree(devname);
return ERR_PTR(-EINVAL);