[ovs-dev] [PATCH] ofp-actions: Right-justify the value in ofpact_reg_load 'subvalue' member.

[Ben Pfaff]

This is what I intended when I suggested using mf_subvalue, but I didn't
notice the difference until after applying the patch.

Signed-off-by: Ben Pfaff <blp at nicira.com>
---
 lib/learn.c       |    4 +++-
 lib/meta-flow.c   |    2 +-
 lib/nx-match.c    |   25 +++++--------------------
 lib/ofp-actions.h |    2 +-
 4 files changed, 10 insertions(+), 23 deletions(-)

diff --git a/lib/learn.c b/lib/learn.c
index 7504227..b9bbc97 100644
--- a/lib/learn.c
+++ b/lib/learn.c
@@ -346,7 +346,9 @@ learn_execute(const struct ofpact_learn *learn, const struct flow *flow,
                 load->dst.field = spec->dst.field;
                 load->dst.ofs = spec->dst.ofs + ofs;
                 load->dst.n_bits = chunk;
-                load->subvalue = value;
+                bitwise_copy(&value, sizeof value, ofs,
+                             &load->subvalue, sizeof load->subvalue, 0,
+                             chunk);
             }
             break;
 
diff --git a/lib/meta-flow.c b/lib/meta-flow.c
index fd33726..aa44ce8 100644
--- a/lib/meta-flow.c
+++ b/lib/meta-flow.c
@@ -2164,7 +2164,7 @@ mf_write_subfield_flow(const struct mf_subfield *sf,
     union mf_value value;
 
     mf_get_value(field, flow, &value);
-    bitwise_copy(x, sizeof *x, sf->ofs, &value, field->n_bytes,
+    bitwise_copy(x, sizeof *x, 0, &value, field->n_bytes,
                  sf->ofs, sf->n_bits);
     mf_set_flow_value(field, &value, flow);
 }
diff --git a/lib/nx-match.c b/lib/nx-match.c
index 1ff58bb..17ef1600 100644
--- a/lib/nx-match.c
+++ b/lib/nx-match.c
@@ -989,7 +989,6 @@ nxm_parse_reg_load(struct ofpact_reg_load *load, const char *s)
 {
     const char *full_s = s;
     uint64_t value = strtoull(s, (char **) &s, 0);
-    ovs_be64 value_be = htonll(value);
 
     if (strncmp(s, "->", 2)) {
         ovs_fatal(0, "%s: missing `->' following value", full_s);
@@ -1005,10 +1004,8 @@ nxm_parse_reg_load(struct ofpact_reg_load *load, const char *s)
                   full_s, value, load->dst.n_bits);
     }
 
-    memset(&load->subvalue, 0, sizeof &load->subvalue);
-    bitwise_copy(&value_be, sizeof value_be, 0,
-                 &load->subvalue, sizeof load->subvalue, load->dst.ofs,
-                 load->dst.n_bits);
+    load->subvalue.be64[0] = htonll(0);
+    load->subvalue.be64[1] = htonll(value);
 }
 
 /* nxm_format_reg_move(), nxm_format_reg_load(). */
@@ -1025,15 +1022,8 @@ nxm_format_reg_move(const struct ofpact_reg_move *move, struct ds *s)
 void
 nxm_format_reg_load(const struct ofpact_reg_load *load, struct ds *s)
 {
-    union mf_subvalue right_justified;
-
-    memset(&right_justified, 0, sizeof right_justified);
-    bitwise_copy(&load->subvalue, sizeof load->subvalue, load->dst.ofs,
-                 &right_justified, sizeof right_justified, 0,
-                 load->dst.n_bits);
-
     ds_put_cstr(s, "load:");
-    mf_format_subvalue(&right_justified, s);
+    mf_format_subvalue(&load->subvalue, s);
     ds_put_cstr(s, "->");
     mf_format_subfield(&load->dst, s);
 }
@@ -1065,10 +1055,7 @@ nxm_reg_load_from_openflow(const struct nx_action_reg_load *narl,
     load->dst.field = mf_from_nxm_header(ntohl(narl->dst));
     load->dst.ofs = nxm_decode_ofs(narl->ofs_nbits);
     load->dst.n_bits = nxm_decode_n_bits(narl->ofs_nbits);
-    memset(&load->subvalue, 0, sizeof &load->subvalue);
-    bitwise_copy(&narl->value, sizeof narl->value, 0,
-                 &load->subvalue, sizeof load->subvalue, load->dst.ofs,
-                 load->dst.n_bits);
+    load->subvalue.be64[1] = narl->value;
 
     /* Reject 'narl' if a bit numbered 'n_bits' or higher is set to 1 in
      * narl->value. */
@@ -1122,9 +1109,7 @@ nxm_reg_load_to_nxast(const struct ofpact_reg_load *load,
     narl = ofputil_put_NXAST_REG_LOAD(openflow);
     narl->ofs_nbits = nxm_encode_ofs_nbits(load->dst.ofs, load->dst.n_bits);
     narl->dst = htonl(load->dst.field->nxm_header);
-    narl->value = htonll(0);
-    bitwise_copy(&load->subvalue, sizeof load->subvalue, load->dst.ofs,
-                 &narl->value, sizeof narl->value, 0, load->dst.n_bits);
+    narl->value = load->subvalue.be64[1];
 }
 
 /* nxm_execute_reg_move(), nxm_execute_reg_load(). */
diff --git a/lib/ofp-actions.h b/lib/ofp-actions.h
index 58383e7..75ccc26 100644
--- a/lib/ofp-actions.h
+++ b/lib/ofp-actions.h
@@ -275,7 +275,7 @@ struct ofpact_reg_move {
 struct ofpact_reg_load {
     struct ofpact ofpact;
     struct mf_subfield dst;
-    union mf_subvalue subvalue;
+    union mf_subvalue subvalue; /* Least-significant bits are used. */
 };
 
 /* OFPACT_SET_TUNNEL.
-- 
1.7.2.5