meta-flow: Add comment.

Acked-by: Numan Siddique <nusiddiq@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

diff --git a/lib/meta-flow.c b/lib/meta-flow.c
index 1724e46e1b976be0175445b3609764df975b59ec..e3274b97f3352b43cfd3c1b1d05b62d7668c37c0 100644 (file)
--- a/lib/meta-flow.c
+++ b/lib/meta-flow.c
@@ -2287,6 +2287,12 @@ mf_set(const struct mf_field *mf,
         *err_str = NULL;
     }
 
+    /* The cases where 'mask' is all-1-bits or all-0-bits were already handled
+     * above[*], so the code below only needs to work for the remaining cases
+     * of a nontrivial mask.
+     *
+     * [*] Except where the field is a tunnel metadata field and 'mask' is
+     *     all-0-bits; see above. */
     switch (mf->id) {
     case MFF_CT_ZONE:
     case MFF_CT_NW_PROTO: