Signed-off-by: Bhanuprakash Bodireddy <[email protected]>
Signed-off-by: Antonio Fischetti <[email protected]>
---
lib/flow.h | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/lib/flow.h b/lib/flow.h
index ea24e28..4eb19ae 100644
--- a/lib/flow.h
+++ b/lib/flow.h
@@ -570,15 +570,27 @@ struct mf_for_each_in_map_aux {
const uint64_t *values;
};
+/*
+ * Parse the bitmap mask of the subtable and output the next value
+ * from the search-key.
+ */
static inline bool
mf_get_next_in_map(struct mf_for_each_in_map_aux *aux,
uint64_t *value)
{
- map_t *map, *fmap;
+ map_t *map; /* map refers to the bitmap mask of the subtable. */
+ map_t *fmap; /* fmap refers to the bitmap of the search-key. */
map_t rm1bit;
+ /* The bitmap mask selects which value must be considered from the
+ * search-key. We process the corresponding 'unit' of size 64 bits.
+ * 'aux->unit' is an index to the current unit of 64 bits. */
while (OVS_UNLIKELY(!*(map = &aux->map.bits[aux->unit]))) {
- /* Skip remaining data in the previous unit. */
+ /* No bits are enabled, so no search-key value will be output.
+ * In case some of the corresponding data chunks in the search-key
+ * bitmap are set, the data chunks must be skipped, as they are not
+ * considered by this mask. This is handled by incrementing aux->values
+ * accordingly. */
aux->values += count_1bits(aux->fmap.bits[aux->unit]);
if (++aux->unit == FLOWMAP_UNITS) {
return false;
@@ -589,7 +601,12 @@ mf_get_next_in_map(struct mf_for_each_in_map_aux *aux,
*map -= rm1bit;
fmap = &aux->fmap.bits[aux->unit];
+ /* If the 8-byte value referred by 'rm1bit' is present in the
+ * search-key return 'value', otherwise return 0. */
if (OVS_LIKELY(*fmap & rm1bit)) {
+ /* The value is in the search-key, if the search-key contains other
+ * values preceeding the 'rm1bit' bit, we consider it trash and the
+ * corresponding data chunks should be skipped accordingly. */
map_t trash = *fmap & (rm1bit - 1);
*fmap -= trash;
@@ -600,6 +617,8 @@ mf_get_next_in_map(struct mf_for_each_in_map_aux *aux,
*value = *aux->values;
} else {
+ /* The search-key does not contain a value that corresponds to
+ * rm1bit. */
*value = 0;
}
return true;
--
2.4.11
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