sfc: store PTP filters in a list

Instead of using a fixed sized array for the PTP filters, use a list.

This is not actually necessary at this point because the filters for
multicast PTP are a fixed number, but this is a preparation for the
following patches adding support for unicast PTP.

To avoid confusion with the new struct type efx_ptp_rxfilter, change the
name of some local variables from rxfilter to spec, given they're of the
type efx_filter_spec.
Reported-by: Yalin Li <yalli@redhat.com>
Signed-off-by: Íñigo Huguet <ihuguet@redhat.com>
Reviewed-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/sfc/ptp.c

@@ -33,6 +33,7 @@
 #include <linux/ip.h>
 #include <linux/udp.h>
 #include <linux/time.h>
+#include <linux/errno.h>
 #include <linux/ktime.h>
 #include <linux/module.h>
 #include <linux/pps_kernel.h>
@@ -118,8 +119,6 @@
 
 #define	PTP_MIN_LENGTH		63
 
-#define PTP_RXFILTERS_LEN	5
-
 #define PTP_ADDR_IPV4		0xe0000181	/* 224.0.1.129 */
 #define PTP_ADDR_IPV6		{0xff, 0x0e, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
 				0, 0x01, 0x81}	/* ff0e::181 */
@@ -213,6 +212,16 @@ struct efx_ptp_timeset {
 	u32 window;	/* Derived: end - start, allowing for wrap */
 };
 
+/**
+ * struct efx_ptp_rxfilter - Filter for PTP packets
+ * @list: Node of the list where the filter is added
+ * @handle: Handle ID for the MCDI filters table
+ */
+struct efx_ptp_rxfilter {
+	struct list_head list;
+	int handle;
+};
+
 /**
  * struct efx_ptp_data - Precision Time Protocol (PTP) state
  * @efx: The NIC context
@@ -229,8 +238,7 @@ struct efx_ptp_timeset {
  * @work: Work task
  * @reset_required: A serious error has occurred and the PTP task needs to be
  *                  reset (disable, enable).
- * @rxfilters: Receive filters when operating
- * @rxfilters_count: Num of installed rxfilters, should be == PTP_RXFILTERS_LEN
+ * @rxfilters_mcast: Receive filters for multicast PTP packets
  * @config: Current timestamp configuration
  * @enabled: PTP operation enabled
  * @mode: Mode in which PTP operating (PTP version)
@@ -299,8 +307,7 @@ struct efx_ptp_data {
 	struct workqueue_struct *workwq;
 	struct work_struct work;
 	bool reset_required;
-	u32 rxfilters[PTP_RXFILTERS_LEN];
-	size_t rxfilters_count;
+	struct list_head rxfilters_mcast;
 	struct hwtstamp_config config;
 	bool enabled;
 	unsigned int mode;
@@ -1292,11 +1299,13 @@ static inline void efx_ptp_process_rx(struct efx_nic *efx, struct sk_buff *skb)
 static void efx_ptp_remove_multicast_filters(struct efx_nic *efx)
 {
 	struct efx_ptp_data *ptp = efx->ptp_data;
+	struct efx_ptp_rxfilter *rxfilter, *tmp;
 
-	while (ptp->rxfilters_count) {
-		ptp->rxfilters_count--;
+	list_for_each_entry_safe(rxfilter, tmp, &ptp->rxfilters_mcast, list) {
 		efx_filter_remove_id_safe(efx, EFX_FILTER_PRI_REQUIRED,
-					  ptp->rxfilters[ptp->rxfilters_count]);
+					  rxfilter->handle);
+		list_del(&rxfilter->list);
+		kfree(rxfilter);
 	}
 }
 
@@ -1311,48 +1320,60 @@ static void efx_ptp_init_filter(struct efx_nic *efx,
 }
 
 static int efx_ptp_insert_filter(struct efx_nic *efx,
-				 struct efx_filter_spec *rxfilter)
+				 struct efx_filter_spec *spec)
 {
 	struct efx_ptp_data *ptp = efx->ptp_data;
+	struct efx_ptp_rxfilter *rxfilter;
+	int rc;
+
+	rxfilter = kzalloc(sizeof(*rxfilter), GFP_KERNEL);
+	if (!rxfilter)
+		return -ENOMEM;
 
-	int rc = efx_filter_insert_filter(efx, rxfilter, true);
+	rc = efx_filter_insert_filter(efx, spec, true);
 	if (rc < 0)
-		return rc;
-	ptp->rxfilters[ptp->rxfilters_count] = rc;
-	ptp->rxfilters_count++;
+		goto fail;
+
+	rxfilter->handle = rc;
+	list_add(&rxfilter->list, &ptp->rxfilters_mcast);
+
 	return 0;
+
+fail:
+	kfree(rxfilter);
+	return rc;
 }
 
 static int efx_ptp_insert_ipv4_filter(struct efx_nic *efx, u16 port)
 {
-	struct efx_filter_spec rxfilter;
+	struct efx_filter_spec spec;
 
-	efx_ptp_init_filter(efx, &rxfilter);
-	efx_filter_set_ipv4_local(&rxfilter, IPPROTO_UDP, htonl(PTP_ADDR_IPV4),
+	efx_ptp_init_filter(efx, &spec);
+	efx_filter_set_ipv4_local(&spec, IPPROTO_UDP, htonl(PTP_ADDR_IPV4),
 				  htons(port));
-	return efx_ptp_insert_filter(efx, &rxfilter);
+	return efx_ptp_insert_filter(efx, &spec);
 }
 
 static int efx_ptp_insert_ipv6_filter(struct efx_nic *efx, u16 port)
 {
 	const struct in6_addr addr = {{PTP_ADDR_IPV6}};
-	struct efx_filter_spec rxfilter;
+	struct efx_filter_spec spec;
 
-	efx_ptp_init_filter(efx, &rxfilter);
-	efx_filter_set_ipv6_local(&rxfilter, IPPROTO_UDP, &addr, htons(port));
-	return efx_ptp_insert_filter(efx, &rxfilter);
+	efx_ptp_init_filter(efx, &spec);
+	efx_filter_set_ipv6_local(&spec, IPPROTO_UDP, &addr, htons(port));
+	return efx_ptp_insert_filter(efx, &spec);
 }
 
 static int efx_ptp_insert_eth_filter(struct efx_nic *efx)
 {
 	const u8 addr[ETH_ALEN] = PTP_ADDR_ETHER;
-	struct efx_filter_spec rxfilter;
+	struct efx_filter_spec spec;
 
-	efx_ptp_init_filter(efx, &rxfilter);
-	efx_filter_set_eth_local(&rxfilter, EFX_FILTER_VID_UNSPEC, addr);
-	rxfilter.match_flags |= EFX_FILTER_MATCH_ETHER_TYPE;
-	rxfilter.ether_type = htons(ETH_P_1588);
-	return efx_ptp_insert_filter(efx, &rxfilter);
+	efx_ptp_init_filter(efx, &spec);
+	efx_filter_set_eth_local(&spec, EFX_FILTER_VID_UNSPEC, addr);
+	spec.match_flags |= EFX_FILTER_MATCH_ETHER_TYPE;
+	spec.ether_type = htons(ETH_P_1588);
+	return efx_ptp_insert_filter(efx, &spec);
 }
 
 static int efx_ptp_insert_multicast_filters(struct efx_nic *efx)
@@ -1360,7 +1381,7 @@ static int efx_ptp_insert_multicast_filters(struct efx_nic *efx)
 	struct efx_ptp_data *ptp = efx->ptp_data;
 	int rc;
 
-	if (!ptp->channel || ptp->rxfilters_count)
+	if (!ptp->channel || !list_empty(&ptp->rxfilters_mcast))
 		return 0;
 
 	/* Must filter on both event and general ports to ensure
@@ -1566,6 +1587,8 @@ int efx_ptp_probe(struct efx_nic *efx, struct efx_channel *channel)
 	for (pos = 0; pos < MAX_RECEIVE_EVENTS; pos++)
 		list_add(&ptp->rx_evts[pos].link, &ptp->evt_free_list);
 
+	INIT_LIST_HEAD(&ptp->rxfilters_mcast);
+
 	/* Get the NIC PTP attributes and set up time conversions */
 	rc = efx_ptp_get_attributes(efx);
 	if (rc < 0)