[PATCH] net/netvsc: Fix on race condition of multiple commands

[Madhuker Mythri <madhukar.mythri@gmail.com>]

When multiple processes issue command requests(like: device info get
and link-status) at same-time, then we could see the command request
failures, due to race-condition of common function execution.

So, to avoid such race-condition introduced a new spin-lock to protect
the code of critical section.

Fixes: 4e9c73e96e83 ("net/netvsc: add Hyper-V network device")
Signed-off-by: Madhuker Mythri <madhukar.mythri@gmail.com>
---
 drivers/net/netvsc/hn_ethdev.c | 1 +
 drivers/net/netvsc/hn_rndis.c  | 2 ++
 drivers/net/netvsc/hn_var.h    | 1 +
 3 files changed, 4 insertions(+)

diff --git a/drivers/net/netvsc/hn_ethdev.c b/drivers/net/netvsc/hn_ethdev.c
index 6584819f4f..b525e287fa 100644
--- a/drivers/net/netvsc/hn_ethdev.c
+++ b/drivers/net/netvsc/hn_ethdev.c
@@ -1310,6 +1310,7 @@ eth_hn_dev_init(struct rte_eth_dev *eth_dev)
 	PMD_INIT_FUNC_TRACE();
 
 	rte_spinlock_init(&hv->hotadd_lock);
+	rte_spinlock_init(&hv->cmd_lock);
 	LIST_INIT(&hv->hotadd_list);
 
 	vmbus = container_of(device, struct rte_vmbus_device, device);
diff --git a/drivers/net/netvsc/hn_rndis.c b/drivers/net/netvsc/hn_rndis.c
index 7c54eebcef..8a0716df89 100644
--- a/drivers/net/netvsc/hn_rndis.c
+++ b/drivers/net/netvsc/hn_rndis.c
@@ -500,8 +500,10 @@ hn_rndis_query(struct hn_data *hv, uint32_t oid,
 	/* Input data immediately follows RNDIS query. */
 	memcpy(req + 1, idata, idlen);
 
+	rte_spinlock_lock(&hv->cmd_lock);
 	error = hn_rndis_execute(hv, rid, req, reqlen,
 				 comp, comp_len, RNDIS_QUERY_CMPLT);
+	rte_spinlock_unlock(&hv->cmd_lock);
 
 	if (error)
 		goto done;
diff --git a/drivers/net/netvsc/hn_var.h b/drivers/net/netvsc/hn_var.h
index 17c1d5d07b..66ed186c0a 100644
--- a/drivers/net/netvsc/hn_var.h
+++ b/drivers/net/netvsc/hn_var.h
@@ -179,6 +179,7 @@ struct hn_data {
 	struct vmbus_channel *channels[HN_MAX_CHANNELS];
 
 	rte_spinlock_t	hotadd_lock;
+	rte_spinlock_t	cmd_lock;
 	LIST_HEAD(hotadd_list, hv_hotadd_context) hotadd_list;
 };
 
-- 
2.50.1 (Apple Git-155)