hw/rdma: Protect against concurrent execution of poll_cq

The function rdma_poll_cq is called from two contexts - completion
handler thread which sense new completion on backend channel and
explicitly as result of guest issuing poll_cq command.

Add lock to protect against concurrent executions.

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Message-Id: <1552300155-25216-4-git-send-email-yuval.shaia@oracle.com>
Reviewed-by: Kamal Heib <kamalheib1@gmail.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/hw/rdma/rdma_backend.c b/hw/rdma/rdma_backend.c
index 37edf42..1897540 100644
--- a/hw/rdma/rdma_backend.c
+++ b/hw/rdma/rdma_backend.c
@@ -70,6 +70,7 @@ static void rdma_poll_cq(RdmaDeviceResources *rdma_dev_res, struct ibv_cq *ibcq)
     BackendCtx *bctx;
     struct ibv_wc wc[2];
 
+    qemu_mutex_lock(&rdma_dev_res->lock);
     do {
         ne = ibv_poll_cq(ibcq, ARRAY_SIZE(wc), wc);
 
@@ -89,6 +90,7 @@ static void rdma_poll_cq(RdmaDeviceResources *rdma_dev_res, struct ibv_cq *ibcq)
             g_free(bctx);
         }
     } while (ne > 0);
+    qemu_mutex_unlock(&rdma_dev_res->lock);
 
     if (ne < 0) {
         rdma_error_report("ibv_poll_cq fail, rc=%d, errno=%d", ne, errno);