net/netvsc: resize event buffer as needed

The event buffer was changed to be a fixed size value,
had a couple of issues. The big one is that rte_free was still
being called for a pointer that was not setup with rte_malloc().

The event buffer was also too small to handle heavy receive
traffic; and running the event buffer out would crash
the application.

Fix by going back to a dynamically resized event buffer.
And grow it by 25% to avoid lots of realloc's.

Fixes: 530af95a7849 ("bus/vmbus: avoid signalling host on read")
Cc: stable@dpdk.org
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>

diff --git a/drivers/net/netvsc/hn_rxtx.c b/drivers/net/netvsc/hn_rxtx.c
index 24abc2a..cb5bc60 100644 (file)
--- a/drivers/net/netvsc/hn_rxtx.c
+++ b/drivers/net/netvsc/hn_rxtx.c
@@ -10,6 +10,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <strings.h>
+#include <malloc.h>
 
 #include <rte_ethdev.h>
 #include <rte_memcpy.h>
@@ -718,16 +719,24 @@ struct hn_rx_queue *hn_rx_queue_alloc(struct hn_data *hv,
 {
        struct hn_rx_queue *rxq;
 
-       rxq = rte_zmalloc_socket("HN_RXQ",
-                                sizeof(*rxq) + HN_RXQ_EVENT_DEFAULT,
+       rxq = rte_zmalloc_socket("HN_RXQ", sizeof(*rxq),
                                 RTE_CACHE_LINE_SIZE, socket_id);
-       if (rxq) {
-               rxq->hv = hv;
-               rxq->chan = hv->channels[queue_id];
-               rte_spinlock_init(&rxq->ring_lock);
-               rxq->port_id = hv->port_id;
-               rxq->queue_id = queue_id;
+       if (!rxq)
+               return NULL;
+
+       rxq->hv = hv;
+       rxq->chan = hv->channels[queue_id];
+       rte_spinlock_init(&rxq->ring_lock);
+       rxq->port_id = hv->port_id;
+       rxq->queue_id = queue_id;
+       rxq->event_sz = HN_RXQ_EVENT_DEFAULT;
+       rxq->event_buf = rte_malloc_socket("HN_EVENTS", HN_RXQ_EVENT_DEFAULT,
+                                          RTE_CACHE_LINE_SIZE, socket_id);
+       if (!rxq->event_buf) {
+               rte_free(rxq);
+               return NULL;
        }
+
        return rxq;
 }
 
@@ -863,19 +872,34 @@ uint32_t hn_process_events(struct hn_data *hv, uint16_t queue_id,
 
        for (;;) {
                const struct vmbus_chanpkt_hdr *pkt;
-               uint32_t len = HN_RXQ_EVENT_DEFAULT;
+               uint32_t len = rxq->event_sz;
                const void *data;
 
+retry:
                ret = rte_vmbus_chan_recv_raw(rxq->chan, rxq->event_buf, &len);
                if (ret == -EAGAIN)
                        break;  /* ring is empty */
 
-               else if (ret == -ENOBUFS)
-                       rte_exit(EXIT_FAILURE, "event buffer not big enough (%u < %u)",
-                                HN_RXQ_EVENT_DEFAULT, len);
-               else if (ret <= 0)
+               if (unlikely(ret == -ENOBUFS)) {
+                       /* event buffer not large enough to read ring */
+
+                       PMD_DRV_LOG(DEBUG,
+                                   "event buffer expansion (need %u)", len);
+                       rxq->event_sz = len + len / 4;
+                       rxq->event_buf = rte_realloc(rxq->event_buf, rxq->event_sz,
+                                                    RTE_CACHE_LINE_SIZE);
+                       if (rxq->event_buf)
+                               goto retry;
+                       /* out of memory, no more events now */
+                       rxq->event_sz = 0;
+                       break;
+               }
+
+               if (unlikely(ret <= 0)) {
+                       /* This indicates a failure to communicate (or worse) */
                        rte_exit(EXIT_FAILURE,
                                 "vmbus ring buffer error: %d", ret);
+               }
 
                bytes_read += ret;
                pkt = (const struct vmbus_chanpkt_hdr *)rxq->event_buf;

diff --git a/drivers/net/netvsc/hn_var.h b/drivers/net/netvsc/hn_var.h
index fec8d7c..b42bd97 100644 (file)
--- a/drivers/net/netvsc/hn_var.h
+++ b/drivers/net/netvsc/hn_var.h
@@ -80,7 +80,7 @@ struct hn_rx_queue {
        struct hn_stats stats;
        uint64_t ring_full;
 
-       uint8_t event_buf[];
+       void *event_buf;
 };