extern int efx_probe_filters(struct efx_nic *efx);
 extern void efx_restore_filters(struct efx_nic *efx);
 extern void efx_remove_filters(struct efx_nic *efx);
-extern int efx_filter_insert_filter(struct efx_nic *efx,
+extern s32 efx_filter_insert_filter(struct efx_nic *efx,
                                    struct efx_filter_spec *spec,
                                    bool replace);
 extern int efx_filter_remove_filter(struct efx_nic *efx,
 
 
 static int efx_filter_search(struct efx_filter_table *table,
                             struct efx_filter_spec *spec, u32 key,
-                            bool for_insert, int *depth_required)
+                            bool for_insert, unsigned int *depth_required)
 {
        unsigned hash, incr, filter_idx, depth, depth_max;
 
  * On success, return the filter ID.
  * On failure, return a negative error code.
  */
-int efx_filter_insert_filter(struct efx_nic *efx, struct efx_filter_spec *spec,
+s32 efx_filter_insert_filter(struct efx_nic *efx, struct efx_filter_spec *spec,
                             bool replace)
 {
        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;
-       int filter_idx, depth;
+       unsigned int filter_idx, depth;
        u32 key;
        int rc;
 
 
 static void efx_filter_table_clear_entry(struct efx_nic *efx,
                                         struct efx_filter_table *table,
-                                        int filter_idx)
+                                        unsigned int filter_idx)
 {
        static efx_oword_t filter;
 
        struct efx_filter_table *table = efx_filter_spec_table(state, spec);
        struct efx_filter_spec *saved_spec;
        efx_oword_t filter;
-       int filter_idx, depth;
+       unsigned int filter_idx, depth;
        u32 key;
        int rc;
 
 {
        struct efx_filter_state *state = efx->filter_state;
        struct efx_filter_table *table = &state->table[table_id];
-       int filter_idx;
+       unsigned int filter_idx;
 
        spin_lock_bh(&state->lock);
 
        enum efx_filter_table_id table_id;
        struct efx_filter_table *table;
        efx_oword_t filter;
-       int filter_idx;
+       unsigned int filter_idx;
 
        spin_lock_bh(&state->lock);