dpif: Make dpif_flow_dump_next() thread-safe.

This patch makes it the caller's responsibility to initialize a
per-thread 'state' object and pass it down to the dpif_flow_dump_next()
implementation. The implementation can expect to be called from multiple
threads with the same 'iter' and different 'state' objects.

When flow_dump_next() returns non-zero, the implementation must ensure
that subsequent calls with the same arguments also return non-zero.
Subsequent calls with the same 'iter' and different 'state' may return
zero, but should make progress towards returning non-zero.

Signed-off-by: Joe Stringer <joestringer@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/utilities/ovs-dpctl.c b/utilities/ovs-dpctl.c
index 66f87fe55..8f1716d05 100644
--- a/utilities/ovs-dpctl.c
+++ b/utilities/ovs-dpctl.c
@@ -764,6 +764,7 @@ dpctl_dump_flows(int argc, char *argv[])
     char *name, *error, *filter = NULL;
     struct flow flow_filter;
     struct flow_wildcards wc_filter;
+    void *state = NULL;
 
     if (argc > 1 && !strncmp(argv[argc - 1], "filter=", 7)) {
         filter = xstrdup(argv[--argc] + 7);
@@ -791,9 +792,10 @@ dpctl_dump_flows(int argc, char *argv[])
 
     ds_init(&ds);
     dpif_flow_dump_start(&flow_dump, dpif);
-    while (dpif_flow_dump_next(&flow_dump, &key, &key_len,
-                               &mask, &mask_len,
-                               &actions, &actions_len, &stats)) {
+    dpif_flow_dump_state_init(dpif, &state);
+    while (dpif_flow_dump_next(&flow_dump, state, &key, &key_len,
+                               &mask, &mask_len, &actions, &actions_len,
+                               &stats)) {
         if (filter) {
             struct flow flow;
             struct flow_wildcards wc;
@@ -824,6 +826,7 @@ dpctl_dump_flows(int argc, char *argv[])
         format_odp_actions(&ds, actions, actions_len);
         printf("%s\n", ds_cstr(&ds));
     }
+    dpif_flow_dump_state_uninit(dpif, state);
     dpif_flow_dump_done(&flow_dump);
 
     free(filter);