[dpdk-dev] [PATCH v3 7/7] net/netvsc: do not spin forever waiting for reply

[Stephen Hemminger]

Because of bugs in driver or host a reply to a request might
never occur. Better to give an error than spin forever.

Fixes: 4e9c73e96e83 ("net/netvsc: add Hyper-V network device")
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
---
 drivers/net/netvsc/hn_rndis.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/net/netvsc/hn_rndis.c b/drivers/net/netvsc/hn_rndis.c
index 6a850ce5f226..d186ddeabda9 100644
--- a/drivers/net/netvsc/hn_rndis.c
+++ b/drivers/net/netvsc/hn_rndis.c
@@ -10,6 +10,7 @@
 #include <stdio.h>
 #include <errno.h>
 #include <unistd.h>
+#include <time.h>
 
 #include <rte_ethdev_driver.h>
 #include <rte_ethdev.h>
@@ -34,6 +35,9 @@
 #include "hn_rndis.h"
 #include "ndis.h"
 
+#define RNDIS_TIMEOUT_SEC 5
+#define RNDIS_DELAY_MS    10
+
 #define HN_RNDIS_XFER_SIZE             0x4000
 
 #define HN_NDIS_TXCSUM_CAP_IP4         \
@@ -354,7 +358,7 @@ void hn_rndis_receive_response(struct hn_data *hv,
        rte_smp_wmb();
 
        if (rte_atomic32_cmpset(&hv->rndis_pending, hdr->rid, 0) == 0) {
-               PMD_DRV_LOG(ERR,
+               PMD_DRV_LOG(NOTICE,
                            "received id %#x pending id %#x",
                            hdr->rid, (uint32_t)hv->rndis_pending);
        }
@@ -377,6 +381,11 @@ static int hn_rndis_exec1(struct hn_data *hv,
                return -EIO;
        }
 
+       if (rid == 0) {
+               PMD_DRV_LOG(ERR, "Invalid request id");
+               return -EINVAL;
+       }
+
        if (comp != NULL &&
            rte_atomic32_cmpset(&hv->rndis_pending, 0, rid) == 0) {
                PMD_DRV_LOG(ERR,
@@ -391,9 +400,26 @@ static int hn_rndis_exec1(struct hn_data *hv,
        }
 
        if (comp) {
+               time_t start = time(NULL);
+
                /* Poll primary channel until response received */
-               while (hv->rndis_pending == rid)
+               while (hv->rndis_pending == rid) {
+                       if (hv->closed)
+                               return -ENETDOWN;
+
+                       if (time(NULL) - start > RNDIS_TIMEOUT_SEC) {
+                               PMD_DRV_LOG(ERR,
+                                           "RNDIS response timed out");
+
+                               rte_atomic32_cmpset(&hv->rndis_pending, rid, 0);
+                               return -ETIMEDOUT;
+                       }
+
+                       if (rte_vmbus_chan_rx_empty(hv->primary->chan))
+                               rte_delay_ms(RNDIS_DELAY_MS);
+
                        hn_process_events(hv, 0, 1);
+               }
 
                memcpy(comp, hv->rndis_resp, comp_len);
        }
-- 
2.26.2