1 files changed, 66 insertions, 23 deletions

diff --git a/drivers/net/ethernet/sfc/filter.c b/drivers/net/ethernet/sfc/filter.c
index 769560a2cb34..0de8daf01c01 100644
--- a/drivers/net/ethernet/sfc/filter.c
+++ b/drivers/net/ethernet/sfc/filter.c
@@ -66,6 +66,10 @@ struct efx_filter_state {
 #endif
 };
 
+static void efx_filter_table_clear_entry(struct efx_nic *efx,
+					 struct efx_filter_table *table,
+					 unsigned int filter_idx);
+
 /* The filter hash function is LFSR polynomial x^16 + x^3 + 1 of a 32-bit
  * key derived from the n-tuple.  The initial LFSR state is 0xffff. */
 static u16 efx_filter_hash(u32 key)
@@ -626,9 +630,9 @@ s32 efx_filter_insert_filter(struct efx_nic *efx, struct efx_filter_spec *spec,
 {
 	struct efx_filter_state *state = efx->filter_state;
 	struct efx_filter_table *table = efx_filter_spec_table(state, spec);
-	struct efx_filter_spec *saved_spec;
 	efx_oword_t filter;
-	unsigned int filter_idx, depth = 0;
+	int rep_index, ins_index;
+	unsigned int depth = 0;
 	int rc;
 
 	if (!table || table->size == 0)
@@ -643,44 +647,74 @@ s32 efx_filter_insert_filter(struct efx_nic *efx, struct efx_filter_spec *spec,
 		BUILD_BUG_ON(EFX_FILTER_INDEX_UC_DEF != 0);
 		BUILD_BUG_ON(EFX_FILTER_INDEX_MC_DEF !=
 			     EFX_FILTER_MC_DEF - EFX_FILTER_UC_DEF);
-		filter_idx = spec->type - EFX_FILTER_INDEX_UC_DEF;
+		rep_index = spec->type - EFX_FILTER_INDEX_UC_DEF;
+		ins_index = rep_index;
 
 		spin_lock_bh(&state->lock);
 	} else {
+		/* Search concurrently for
+		 * (1) a filter to be replaced (rep_index): any filter
+		 *     with the same match values, up to the current
+		 *     search depth for this type, and
+		 * (2) the insertion point (ins_index): (1) or any
+		 *     free slot before it or up to the maximum search
+		 *     depth for this priority
+		 * We fail if we cannot find (2).
+		 *
+		 * We can stop once either
+		 * (a) we find (1), in which case we have definitely
+		 *     found (2) as well; or
+		 * (b) we have searched exhaustively for (1), and have
+		 *     either found (2) or searched exhaustively for it
+		 */
 		u32 key = efx_filter_build(&filter, spec);
 		unsigned int hash = efx_filter_hash(key);
 		unsigned int incr = efx_filter_increment(key);
-		unsigned int depth_max =
+		unsigned int max_rep_depth = table->search_depth[spec->type];
+		unsigned int max_ins_depth =
 			spec->priority <= EFX_FILTER_PRI_HINT ?
 			FILTER_CTL_SRCH_HINT_MAX : FILTER_CTL_SRCH_MAX;
+		unsigned int i = hash & (table->size - 1);
 
-		filter_idx = hash & (table->size - 1);
+		ins_index = -1;
 		depth = 1;
 
 		spin_lock_bh(&state->lock);
 
 		for (;;) {
-			if (!test_bit(filter_idx, table->used_bitmap) ||
-			    efx_filter_equal(spec, &table->spec[filter_idx]))
+			if (!test_bit(i, table->used_bitmap)) {
+				if (ins_index < 0)
+					ins_index = i;
+			} else if (efx_filter_equal(spec, &table->spec[i])) {
+				/* Case (a) */
+				if (ins_index < 0)
+					ins_index = i;
+				rep_index = i;
 				break;
+			}
 
-			/* Return failure if we reached the maximum search
-			 * depth
-			 */
-			if (depth == depth_max) {
-				rc = -EBUSY;
-				goto out;
+			if (depth >= max_rep_depth &&
+			    (ins_index >= 0 || depth >= max_ins_depth)) {
+				/* Case (b) */
+				if (ins_index < 0) {
+					rc = -EBUSY;
+					goto out;
+				}
+				rep_index = -1;
+				break;
 			}
 
-			filter_idx = (filter_idx + incr) & (table->size - 1);
+			i = (i + incr) & (table->size - 1);
 			++depth;
 		}
 	}
 
-	saved_spec = &table->spec[filter_idx];
+	/* If we found a filter to be replaced, check whether we
+	 * should do so
+	 */
+	if (rep_index >= 0) {
+		struct efx_filter_spec *saved_spec = &table->spec[rep_index];
 
-	if (test_bit(filter_idx, table->used_bitmap)) {
-		/* Should we replace the existing filter? */
 		if (spec->priority == saved_spec->priority && !replace_equal) {
 			rc = -EEXIST;
 			goto out;
@@ -689,11 +723,14 @@ s32 efx_filter_insert_filter(struct efx_nic *efx, struct efx_filter_spec *spec,
 			rc = -EPERM;
 			goto out;
 		}
-	} else {
-		__set_bit(filter_idx, table->used_bitmap);
+	}
+
+	/* Insert the filter */
+	if (ins_index != rep_index) {
+		__set_bit(ins_index, table->used_bitmap);
 		++table->used;
 	}
-	*saved_spec = *spec;
+	table->spec[ins_index] = *spec;
 
 	if (table->id == EFX_FILTER_TABLE_RX_DEF) {
 		efx_filter_push_rx_config(efx);
@@ -707,13 +744,19 @@ s32 efx_filter_insert_filter(struct efx_nic *efx, struct efx_filter_spec *spec,
 		}
 
 		efx_writeo(efx, &filter,
-			   table->offset + table->step * filter_idx);
+			   table->offset + table->step * ins_index);
+
+		/* If we were able to replace a filter by inserting
+		 * at a lower depth, clear the replaced filter
+		 */
+		if (ins_index != rep_index && rep_index >= 0)
+			efx_filter_table_clear_entry(efx, table, rep_index);
 	}
 
 	netif_vdbg(efx, hw, efx->net_dev,
 		   "%s: filter type %d index %d rxq %u set",
-		   __func__, spec->type, filter_idx, spec->dmaq_id);
-	rc = efx_filter_make_id(spec, filter_idx);
+		   __func__, spec->type, ins_index, spec->dmaq_id);
+	rc = efx_filter_make_id(spec, ins_index);
 
 out:
 	spin_unlock_bh(&state->lock);