[ltt-dev] [PATCH 08/10] Return -EEXIST when the old cpu call_rcu_data has not been removed

[Lai Jiangshan]

To make it matches the comments.

It is the caller's responsibility to use
set_cpu_call_rcu_data(cpu, NULL) to remove the CPU's
call_rcu_data structure and dispose it.

Signed-off-by: Lai Jiangshan <laijs at cn.fujitsu.com>
---
 urcu-call-rcu-impl.h |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/urcu-call-rcu-impl.h b/urcu-call-rcu-impl.h
index c822646..ae93468 100644
--- a/urcu-call-rcu-impl.h
+++ b/urcu-call-rcu-impl.h
@@ -396,11 +396,19 @@ int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp)
 		errno = EINVAL;
 		return -EINVAL;
 	}
+
 	if (per_cpu_call_rcu_data == NULL) {
 		call_rcu_unlock(&call_rcu_mutex);
 		errno = ENOMEM;
 		return -ENOMEM;
 	}
+
+	if (per_cpu_call_rcu_data[cpu] != NULL && crdp != NULL) {
+		call_rcu_unlock(&call_rcu_mutex);
+		errno = EEXIST;
+		return -EEXIST;
+	}
+
 	per_cpu_call_rcu_data[cpu] = crdp;
 	call_rcu_unlock(&call_rcu_mutex);
 	return 0;
-- 
1.7.4.4