sfc: add functions to allocate/free MAE counters

efx_tc_flower_get_counter_index() will create an MAE counter mapped to
 the passed (TC filter) cookie, or increment the reference if one already
 exists for that cookie.
Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/mae.c

@@ -434,6 +434,57 @@ int efx_mae_match_check_caps(struct efx_nic *efx,
 #undef CHECK_BIT
 #undef CHECK
 
+int efx_mae_allocate_counter(struct efx_nic *efx, struct efx_tc_counter *cnt)
+{
+	MCDI_DECLARE_BUF(outbuf, MC_CMD_MAE_COUNTER_ALLOC_OUT_LEN(1));
+	MCDI_DECLARE_BUF(inbuf, MC_CMD_MAE_COUNTER_ALLOC_V2_IN_LEN);
+	size_t outlen;
+	int rc;
+
+	if (!cnt)
+		return -EINVAL;
+
+	MCDI_SET_DWORD(inbuf, MAE_COUNTER_ALLOC_V2_IN_REQUESTED_COUNT, 1);
+	MCDI_SET_DWORD(inbuf, MAE_COUNTER_ALLOC_V2_IN_COUNTER_TYPE, cnt->type);
+	rc = efx_mcdi_rpc(efx, MC_CMD_MAE_COUNTER_ALLOC, inbuf, sizeof(inbuf),
+			  outbuf, sizeof(outbuf), &outlen);
+	if (rc)
+		return rc;
+	/* pcol says this can't happen, since count is 1 */
+	if (outlen < sizeof(outbuf))
+		return -EIO;
+	cnt->fw_id = MCDI_DWORD(outbuf, MAE_COUNTER_ALLOC_OUT_COUNTER_ID);
+	cnt->gen = MCDI_DWORD(outbuf, MAE_COUNTER_ALLOC_OUT_GENERATION_COUNT);
+	return 0;
+}
+
+int efx_mae_free_counter(struct efx_nic *efx, struct efx_tc_counter *cnt)
+{
+	MCDI_DECLARE_BUF(outbuf, MC_CMD_MAE_COUNTER_FREE_OUT_LEN(1));
+	MCDI_DECLARE_BUF(inbuf, MC_CMD_MAE_COUNTER_FREE_V2_IN_LEN);
+	size_t outlen;
+	int rc;
+
+	MCDI_SET_DWORD(inbuf, MAE_COUNTER_FREE_V2_IN_COUNTER_ID_COUNT, 1);
+	MCDI_SET_DWORD(inbuf, MAE_COUNTER_FREE_V2_IN_FREE_COUNTER_ID, cnt->fw_id);
+	MCDI_SET_DWORD(inbuf, MAE_COUNTER_FREE_V2_IN_COUNTER_TYPE, cnt->type);
+	rc = efx_mcdi_rpc(efx, MC_CMD_MAE_COUNTER_FREE, inbuf, sizeof(inbuf),
+			  outbuf, sizeof(outbuf), &outlen);
+	if (rc)
+		return rc;
+	/* pcol says this can't happen, since count is 1 */
+	if (outlen < sizeof(outbuf))
+		return -EIO;
+	/* FW freed a different ID than we asked for, should also never happen.
+	 * Warn because it means we've now got a different idea to the FW of
+	 * what counters exist, which could cause mayhem later.
+	 */
+	if (WARN_ON(MCDI_DWORD(outbuf, MAE_COUNTER_FREE_OUT_FREED_COUNTER_ID) !=
+		    cnt->fw_id))
+		return -EIO;
+	return 0;
+}
+
 static bool efx_mae_asl_id(u32 id)
 {
 	return !!(id & BIT(31));

drivers/net/ethernet/sfc/mae.h

@@ -45,6 +45,9 @@ int efx_mae_match_check_caps(struct efx_nic *efx,
 			     const struct efx_tc_match_fields *mask,
 			     struct netlink_ext_ack *extack);
 
+int efx_mae_allocate_counter(struct efx_nic *efx, struct efx_tc_counter *cnt);
+int efx_mae_free_counter(struct efx_nic *efx, struct efx_tc_counter *cnt);
+
 int efx_mae_alloc_action_set(struct efx_nic *efx, struct efx_tc_action_set *act);
 int efx_mae_free_action_set(struct efx_nic *efx, u32 fw_id);
 

drivers/net/ethernet/sfc/tc_counters.c

@@ -74,6 +74,115 @@ void efx_tc_fini_counters(struct efx_nic *efx)
 	rhashtable_free_and_destroy(&efx->tc->counter_ht, efx_tc_counter_free, NULL);
 }
 
+/* Counter allocation */
+
+static struct efx_tc_counter *efx_tc_flower_allocate_counter(struct efx_nic *efx,
+							     int type)
+{
+	struct efx_tc_counter *cnt;
+	int rc, rc2;
+
+	cnt = kzalloc(sizeof(*cnt), GFP_USER);
+	if (!cnt)
+		return ERR_PTR(-ENOMEM);
+
+	cnt->type = type;
+
+	rc = efx_mae_allocate_counter(efx, cnt);
+	if (rc)
+		goto fail1;
+	rc = rhashtable_insert_fast(&efx->tc->counter_ht, &cnt->linkage,
+				    efx_tc_counter_ht_params);
+	if (rc)
+		goto fail2;
+	return cnt;
+fail2:
+	/* If we get here, it implies that we couldn't insert into the table,
+	 * which in turn probably means that the fw_id was already taken.
+	 * In that case, it's unclear whether we really 'own' the fw_id; but
+	 * the firmware seemed to think we did, so it's proper to free it.
+	 */
+	rc2 = efx_mae_free_counter(efx, cnt);
+	if (rc2)
+		netif_warn(efx, hw, efx->net_dev,
+			   "Failed to free MAE counter %u, rc %d\n",
+			   cnt->fw_id, rc2);
+fail1:
+	kfree(cnt);
+	return ERR_PTR(rc > 0 ? -EIO : rc);
+}
+
+static void efx_tc_flower_release_counter(struct efx_nic *efx,
+					  struct efx_tc_counter *cnt)
+{
+	int rc;
+
+	rhashtable_remove_fast(&efx->tc->counter_ht, &cnt->linkage,
+			       efx_tc_counter_ht_params);
+	rc = efx_mae_free_counter(efx, cnt);
+	if (rc)
+		netif_warn(efx, hw, efx->net_dev,
+			   "Failed to free MAE counter %u, rc %d\n",
+			   cnt->fw_id, rc);
+	/* This doesn't protect counter updates coming in arbitrarily long
+	 * after we deleted the counter.  The RCU just ensures that we won't
+	 * free the counter while another thread has a pointer to it.
+	 * Ensuring we don't update the wrong counter if the ID gets re-used
+	 * is handled by the generation count.
+	 */
+	synchronize_rcu();
+	kfree(cnt);
+}
+
+/* TC cookie to counter mapping */
+
+void efx_tc_flower_put_counter_index(struct efx_nic *efx,
+				     struct efx_tc_counter_index *ctr)
+{
+	if (!refcount_dec_and_test(&ctr->ref))
+		return; /* still in use */
+	rhashtable_remove_fast(&efx->tc->counter_id_ht, &ctr->linkage,
+			       efx_tc_counter_id_ht_params);
+	efx_tc_flower_release_counter(efx, ctr->cnt);
+	kfree(ctr);
+}
+
+struct efx_tc_counter_index *efx_tc_flower_get_counter_index(
+				struct efx_nic *efx, unsigned long cookie,
+				enum efx_tc_counter_type type)
+{
+	struct efx_tc_counter_index *ctr, *old;
+	struct efx_tc_counter *cnt;
+
+	ctr = kzalloc(sizeof(*ctr), GFP_USER);
+	if (!ctr)
+		return ERR_PTR(-ENOMEM);
+	ctr->cookie = cookie;
+	old = rhashtable_lookup_get_insert_fast(&efx->tc->counter_id_ht,
+						&ctr->linkage,
+						efx_tc_counter_id_ht_params);
+	if (old) {
+		/* don't need our new entry */
+		kfree(ctr);
+		if (!refcount_inc_not_zero(&old->ref))
+			return ERR_PTR(-EAGAIN);
+		/* existing entry found */
+		ctr = old;
+	} else {
+		cnt = efx_tc_flower_allocate_counter(efx, type);
+		if (IS_ERR(cnt)) {
+			rhashtable_remove_fast(&efx->tc->counter_id_ht,
+					       &ctr->linkage,
+					       efx_tc_counter_id_ht_params);
+			kfree(ctr);
+			return (void *)cnt; /* it's an ERR_PTR */
+		}
+		ctr->cnt = cnt;
+		refcount_set(&ctr->ref, 1);
+	}
+	return ctr;
+}
+
 /* TC Channel.  Counter updates are delivered on this channel's RXQ. */
 
 static void efx_tc_handle_no_channel(struct efx_nic *efx)

drivers/net/ethernet/sfc/tc_counters.h

@@ -26,6 +26,7 @@ struct efx_tc_counter {
 	u32 fw_id; /* index in firmware counter table */
 	enum efx_tc_counter_type type;
 	struct rhash_head linkage; /* efx->tc->counter_ht */
+	u32 gen; /* Generation count at which this counter is current */
 };
 
 struct efx_tc_counter_index {
@@ -40,6 +41,12 @@ int efx_tc_init_counters(struct efx_nic *efx);
 void efx_tc_destroy_counters(struct efx_nic *efx);
 void efx_tc_fini_counters(struct efx_nic *efx);
 
+struct efx_tc_counter_index *efx_tc_flower_get_counter_index(
+				struct efx_nic *efx, unsigned long cookie,
+				enum efx_tc_counter_type type);
+void efx_tc_flower_put_counter_index(struct efx_nic *efx,
+				     struct efx_tc_counter_index *ctr);
+
 extern const struct efx_channel_type efx_tc_channel_type;
 
 #endif /* EFX_TC_COUNTERS_H */