[dpdk-dev] [PATCH v2] kni: Fix request overwritten

[Elad Nachman <eladv6@gmail.com>]

Fix lack of multiple KNI requests handling support by introducing a
request in progress flag which will fail additional requests with
EAGAIN return code if the original request has not been processed
by user-space.

Bugzilla ID: 809
 
Signed-off-by: Elad Nachman <eladv6@gmail.com>
---
 kernel/linux/kni/kni_net.c | 9 +++++++++
 lib/kni/rte_kni.c          | 2 ++
 lib/kni/rte_kni_common.h   | 1 +
 3 files changed, 12 insertions(+)

diff --git a/kernel/linux/kni/kni_net.c b/kernel/linux/kni/kni_net.c
index 611719b5ee..927bf9537c 100644
--- a/kernel/linux/kni/kni_net.c
+++ b/kernel/linux/kni/kni_net.c
@@ -110,6 +110,7 @@ kni_net_process_request(struct net_device *dev, struct rte_kni_request *req)
 	void *resp_va;
 	uint32_t num;
 	int ret_val;
+	struct rte_kni_request *cur_req;
 
 	ASSERT_RTNL();
 
@@ -123,7 +124,15 @@ kni_net_process_request(struct net_device *dev, struct rte_kni_request *req)
 
 	mutex_lock(&kni->sync_lock);
 
+	/* Check that existing request has been processed: */
+	cur_req = (struct rte_kni_request *)kni->sync_kva;
+	if (cur_req->req_in_progress) {
+		ret = -EAGAIN;
+		goto fail;
+	}
+
 	/* Construct data */
+	req->req_in_progress = 1;
 	memcpy(kni->sync_kva, req, sizeof(struct rte_kni_request));
 	num = kni_fifo_put(kni->req_q, &kni->sync_va, 1);
 	if (num < 1) {
diff --git a/lib/kni/rte_kni.c b/lib/kni/rte_kni.c
index d3e236005e..0599e0356a 100644
--- a/lib/kni/rte_kni.c
+++ b/lib/kni/rte_kni.c
@@ -307,6 +307,7 @@ rte_kni_alloc(struct rte_mempool *pktmbuf_pool,
 	kni->sync_addr = kni->m_sync_addr->addr;
 	dev_info.sync_va = kni->m_sync_addr->addr;
 	dev_info.sync_phys = kni->m_sync_addr->iova;
+	memset(kni->sync_addr, 0, sizeof(struct rte_kni_request));
 
 	kni->pktmbuf_pool = pktmbuf_pool;
 	kni->group_id = conf->group_id;
@@ -596,6 +597,7 @@ rte_kni_handle_request(struct rte_kni *kni)
 		ret = kni_fifo_put(kni->resp_q, (void **)&req, 1);
 	else
 		ret = 1;
+	req->req_in_progress = 0;
 	if (ret != 1) {
 		RTE_LOG(ERR, KNI, "Fail to put the muf back to resp_q\n");
 		return -1; /* It is an error of can't putting the mbuf back */
diff --git a/lib/kni/rte_kni_common.h b/lib/kni/rte_kni_common.h
index b547ea5501..1973e467f9 100644
--- a/lib/kni/rte_kni_common.h
+++ b/lib/kni/rte_kni_common.h
@@ -40,6 +40,7 @@ enum rte_kni_req_id {
  */
 struct rte_kni_request {
 	uint32_t req_id;             /**< Request id */
+	uint32_t req_in_progress;    /**< Request in progress flag */
 	RTE_STD_C11
 	union {
 		uint32_t new_mtu;    /**< New MTU */
-- 
2.17.1