[PATCH ncns v1 3/4] chnet: ring: Make sure we are holding the lock when calling `cqe_size()`

[Ammar Faizi <ammarfaizi2@gnuweeb.org>]

In `CNRingCtx::WaitCQE`, the first call to `cqe_size()` is not protected
by the cqe_lock. Protect it.

Fixes: a04f582cdbdbcefa3c08ce123696d0fd08a20702 ("chnet: Full refactor CNRing and change the interface")
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
---
 chnet/chnet_ring.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/chnet/chnet_ring.cc b/chnet/chnet_ring.cc
index c9a3da5..e9d0d57 100644
--- a/chnet/chnet_ring.cc
+++ b/chnet/chnet_ring.cc
@@ -366,6 +366,7 @@ uint32_t CNRingCtx::SubmitSQE(uint32_t to_submit)
 void CNRingCtx::WaitCQE(uint32_t to_wait)
 {
 	uint32_t max_to_wait;
+	uint32_t cq_size;
 
 	if (unlikely(!to_wait))
 		return;
@@ -375,10 +376,11 @@ void CNRingCtx::WaitCQE(uint32_t to_wait)
 		to_wait = max_to_wait;
 
 	NotifyWaitCQEFreeSlot();
-	if (to_wait <= cqe_size())
-		return;
 
 	std::unique_lock<std::mutex> cqe_lock(state_->cqe_lock_);
+	cq_size = cqe_size();
+	if (to_wait <= cq_size)
+		return;
 
 	state_->cqe_to_wait_.store(to_wait);
 	state_->cqe_cond_.wait(cqe_lock, [this, to_wait]{
-- 
Ammar Faizi