eth: fbnic: store NAPIs in an array instead of the list

We will need an array for storing NAPIs in the upcoming IRQ handler
reuse rework. Replace the current list we have, so that we are able
to reuse it later.

In a few places replace i as the iterator with t when we iterate
over triads, this seems slightly less confusing than having
i, j, k variables.

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

drivers/net/ethernet/meta/fbnic/fbnic_netdev.c

@@ -615,7 +615,6 @@ struct net_device *fbnic_netdev_alloc(struct fbnic_dev *fbd)
 
 	fbn->netdev = netdev;
 	fbn->fbd = fbd;
-	INIT_LIST_HEAD(&fbn->napis);
 
 	fbn->txq_size = FBNIC_TXQ_SIZE_DEFAULT;
 	fbn->hpq_size = FBNIC_HPQ_SIZE_DEFAULT;

drivers/net/ethernet/meta/fbnic/fbnic_netdev.h

@@ -11,10 +11,14 @@
 #include "fbnic_rpc.h"
 #include "fbnic_txrx.h"
 
+#define FBNIC_MAX_NAPI_VECTORS		128u
+
 struct fbnic_net {
 	struct fbnic_ring *tx[FBNIC_MAX_TXQS];
 	struct fbnic_ring *rx[FBNIC_MAX_RXQS];
 
+	struct fbnic_napi_vector *napi[FBNIC_MAX_NAPI_VECTORS];
+
 	struct net_device *netdev;
 	struct fbnic_dev *fbd;
 
@@ -56,8 +60,6 @@ struct fbnic_net {
 
 	/* Time stampinn filter config */
 	struct kernel_hwtstamp_config hwtstamp_config;
-
-	struct list_head napis;
 };
 
 int __fbnic_open(struct fbnic_net *fbn);

drivers/net/ethernet/meta/fbnic/fbnic_txrx.c

@@ -1116,16 +1116,17 @@ static void fbnic_free_napi_vector(struct fbnic_net *fbn,
 	fbnic_free_irq(fbd, v_idx, nv);
 	page_pool_destroy(nv->page_pool);
 	netif_napi_del(&nv->napi);
-	list_del(&nv->napis);
+	fbn->napi[fbnic_napi_idx(nv)] = NULL;
 	kfree(nv);
 }
 
 void fbnic_free_napi_vectors(struct fbnic_net *fbn)
 {
-	struct fbnic_napi_vector *nv, *temp;
+	int i;
 
-	list_for_each_entry_safe(nv, temp, &fbn->napis, napis)
-		fbnic_free_napi_vector(fbn, nv);
+	for (i = 0; i < fbn->num_napi; i++)
+		if (fbn->napi[i])
+			fbnic_free_napi_vector(fbn, fbn->napi[i]);
 }
 
 static void fbnic_name_napi_vector(struct fbnic_napi_vector *nv)
@@ -1222,7 +1223,7 @@ static int fbnic_alloc_napi_vector(struct fbnic_dev *fbd, struct fbnic_net *fbn,
 	nv->v_idx = v_idx;
 
 	/* Tie napi to netdev */
-	list_add(&nv->napis, &fbn->napis);
+	fbn->napi[fbnic_napi_idx(nv)] = nv;
 	netif_napi_add(fbn->netdev, &nv->napi, fbnic_poll);
 
 	/* Record IRQ to NAPI struct */
@@ -1307,7 +1308,7 @@ static int fbnic_alloc_napi_vector(struct fbnic_dev *fbd, struct fbnic_net *fbn,
 	page_pool_destroy(nv->page_pool);
 napi_del:
 	netif_napi_del(&nv->napi);
-	list_del(&nv->napis);
+	fbn->napi[fbnic_napi_idx(nv)] = NULL;
 	kfree(nv);
 	return err;
 }
@@ -1612,28 +1613,27 @@ static int fbnic_alloc_nv_resources(struct fbnic_net *fbn,
 
 void fbnic_free_resources(struct fbnic_net *fbn)
 {
-	struct fbnic_napi_vector *nv;
+	int i;
 
-	list_for_each_entry(nv, &fbn->napis, napis)
-		fbnic_free_nv_resources(fbn, nv);
+	for (i = 0; i < fbn->num_napi; i++)
+		fbnic_free_nv_resources(fbn, fbn->napi[i]);
 }
 
 int fbnic_alloc_resources(struct fbnic_net *fbn)
 {
-	struct fbnic_napi_vector *nv;
-	int err = -ENODEV;
+	int i, err = -ENODEV;
 
-	list_for_each_entry(nv, &fbn->napis, napis) {
-		err = fbnic_alloc_nv_resources(fbn, nv);
+	for (i = 0; i < fbn->num_napi; i++) {
+		err = fbnic_alloc_nv_resources(fbn, fbn->napi[i]);
 		if (err)
 			goto free_resources;
 	}
 
 	return 0;
 
 free_resources:
-	list_for_each_entry_continue_reverse(nv, &fbn->napis, napis)
-		fbnic_free_nv_resources(fbn, nv);
+	while (i--)
+		fbnic_free_nv_resources(fbn, fbn->napi[i]);
 
 	return err;
 }
@@ -1670,33 +1670,34 @@ static void fbnic_disable_rcq(struct fbnic_ring *rxr)
 
 void fbnic_napi_disable(struct fbnic_net *fbn)
 {
-	struct fbnic_napi_vector *nv;
+	int i;
 
-	list_for_each_entry(nv, &fbn->napis, napis) {
-		napi_disable(&nv->napi);
+	for (i = 0; i < fbn->num_napi; i++) {
+		napi_disable(&fbn->napi[i]->napi);
 
-		fbnic_nv_irq_disable(nv);
+		fbnic_nv_irq_disable(fbn->napi[i]);
 	}
 }
 
 void fbnic_disable(struct fbnic_net *fbn)
 {
 	struct fbnic_dev *fbd = fbn->fbd;
-	struct fbnic_napi_vector *nv;
-	int i, j;
+	int i, j, t;
+
+	for (i = 0; i < fbn->num_napi; i++) {
+		struct fbnic_napi_vector *nv = fbn->napi[i];
 
-	list_for_each_entry(nv, &fbn->napis, napis) {
 		/* Disable Tx queue triads */
-		for (i = 0; i < nv->txt_count; i++) {
-			struct fbnic_q_triad *qt = &nv->qt[i];
+		for (t = 0; t < nv->txt_count; t++) {
+			struct fbnic_q_triad *qt = &nv->qt[t];
 
 			fbnic_disable_twq0(&qt->sub0);
 			fbnic_disable_tcq(&qt->cmpl);
 		}
 
 		/* Disable Rx queue triads */
-		for (j = 0; j < nv->rxt_count; j++, i++) {
-			struct fbnic_q_triad *qt = &nv->qt[i];
+		for (j = 0; j < nv->rxt_count; j++, t++) {
+			struct fbnic_q_triad *qt = &nv->qt[t];
 
 			fbnic_disable_bdq(&qt->sub0, &qt->sub1);
 			fbnic_disable_rcq(&qt->cmpl);
@@ -1792,14 +1793,15 @@ int fbnic_wait_all_queues_idle(struct fbnic_dev *fbd, bool may_fail)
 
 void fbnic_flush(struct fbnic_net *fbn)
 {
-	struct fbnic_napi_vector *nv;
+	int i;
 
-	list_for_each_entry(nv, &fbn->napis, napis) {
-		int i, j;
+	for (i = 0; i < fbn->num_napi; i++) {
+		struct fbnic_napi_vector *nv = fbn->napi[i];
+		int j, t;
 
 		/* Flush any processed Tx Queue Triads and drop the rest */
-		for (i = 0; i < nv->txt_count; i++) {
-			struct fbnic_q_triad *qt = &nv->qt[i];
+		for (t = 0; t < nv->txt_count; t++) {
+			struct fbnic_q_triad *qt = &nv->qt[t];
 			struct netdev_queue *tx_queue;
 
 			/* Clean the work queues of unprocessed work */
@@ -1823,8 +1825,8 @@ void fbnic_flush(struct fbnic_net *fbn)
 		}
 
 		/* Flush any processed Rx Queue Triads and drop the rest */
-		for (j = 0; j < nv->rxt_count; j++, i++) {
-			struct fbnic_q_triad *qt = &nv->qt[i];
+		for (j = 0; j < nv->rxt_count; j++, t++) {
+			struct fbnic_q_triad *qt = &nv->qt[t];
 
 			/* Clean the work queues of unprocessed work */
 			fbnic_clean_bdq(nv, 0, &qt->sub0, qt->sub0.tail);
@@ -1845,14 +1847,15 @@ void fbnic_flush(struct fbnic_net *fbn)
 
 void fbnic_fill(struct fbnic_net *fbn)
 {
-	struct fbnic_napi_vector *nv;
+	int i;
 
-	list_for_each_entry(nv, &fbn->napis, napis) {
-		int i, j;
+	for (i = 0; i < fbn->num_napi; i++) {
+		struct fbnic_napi_vector *nv = fbn->napi[i];
+		int j, t;
 
 		/* Configure NAPI mapping for Tx */
-		for (i = 0; i < nv->txt_count; i++) {
-			struct fbnic_q_triad *qt = &nv->qt[i];
+		for (t = 0; t < nv->txt_count; t++) {
+			struct fbnic_q_triad *qt = &nv->qt[t];
 
 			/* Nothing to do if Tx queue is disabled */
 			if (qt->sub0.flags & FBNIC_RING_F_DISABLED)
@@ -1866,8 +1869,8 @@ void fbnic_fill(struct fbnic_net *fbn)
 		/* Configure NAPI mapping and populate pages
 		 * in the BDQ rings to use for Rx
 		 */
-		for (j = 0; j < nv->rxt_count; j++, i++) {
-			struct fbnic_q_triad *qt = &nv->qt[i];
+		for (j = 0; j < nv->rxt_count; j++, t++) {
+			struct fbnic_q_triad *qt = &nv->qt[t];
 
 			/* Associate Rx queue with NAPI */
 			netif_queue_set_napi(nv->napi.dev, qt->cmpl.q_idx,
@@ -2025,21 +2028,23 @@ static void fbnic_enable_rcq(struct fbnic_napi_vector *nv,
 void fbnic_enable(struct fbnic_net *fbn)
 {
 	struct fbnic_dev *fbd = fbn->fbd;
-	struct fbnic_napi_vector *nv;
-	int i, j;
+	int i;
+
+	for (i = 0; i < fbn->num_napi; i++) {
+		struct fbnic_napi_vector *nv = fbn->napi[i];
+		int j, t;
 
-	list_for_each_entry(nv, &fbn->napis, napis) {
 		/* Setup Tx Queue Triads */
-		for (i = 0; i < nv->txt_count; i++) {
-			struct fbnic_q_triad *qt = &nv->qt[i];
+		for (t = 0; t < nv->txt_count; t++) {
+			struct fbnic_q_triad *qt = &nv->qt[t];
 
 			fbnic_enable_twq0(&qt->sub0);
 			fbnic_enable_tcq(nv, &qt->cmpl);
 		}
 
 		/* Setup Rx Queue Triads */
-		for (j = 0; j < nv->rxt_count; j++, i++) {
-			struct fbnic_q_triad *qt = &nv->qt[i];
+		for (j = 0; j < nv->rxt_count; j++, t++) {
+			struct fbnic_q_triad *qt = &nv->qt[t];
 
 			fbnic_enable_bdq(&qt->sub0, &qt->sub1);
 			fbnic_config_drop_mode_rcq(nv, &qt->cmpl);
@@ -2064,10 +2069,11 @@ void fbnic_napi_enable(struct fbnic_net *fbn)
 {
 	u32 irqs[FBNIC_MAX_MSIX_VECS / 32] = {};
 	struct fbnic_dev *fbd = fbn->fbd;
-	struct fbnic_napi_vector *nv;
 	int i;
 
-	list_for_each_entry(nv, &fbn->napis, napis) {
+	for (i = 0; i < fbn->num_napi; i++) {
+		struct fbnic_napi_vector *nv = fbn->napi[i];
+
 		napi_enable(&nv->napi);
 
 		fbnic_nv_irq_enable(nv);
@@ -2096,17 +2102,18 @@ void fbnic_napi_depletion_check(struct net_device *netdev)
 	struct fbnic_net *fbn = netdev_priv(netdev);
 	u32 irqs[FBNIC_MAX_MSIX_VECS / 32] = {};
 	struct fbnic_dev *fbd = fbn->fbd;
-	struct fbnic_napi_vector *nv;
-	int i, j;
+	int i, j, t;
+
+	for (i = 0; i < fbn->num_napi; i++) {
+		struct fbnic_napi_vector *nv = fbn->napi[i];
 
-	list_for_each_entry(nv, &fbn->napis, napis) {
 		/* Find RQs which are completely out of pages */
-		for (i = nv->txt_count, j = 0; j < nv->rxt_count; j++, i++) {
+		for (t = nv->txt_count, j = 0; j < nv->rxt_count; j++, t++) {
 			/* Assume 4 pages is always enough to fit a packet
 			 * and therefore generate a completion and an IRQ.
 			 */
-			if (fbnic_desc_used(&nv->qt[i].sub0) < 4 ||
-			    fbnic_desc_used(&nv->qt[i].sub1) < 4)
+			if (fbnic_desc_used(&nv->qt[t].sub0) < 4 ||
+			    fbnic_desc_used(&nv->qt[t].sub1) < 4)
 				irqs[nv->v_idx / 32] |= BIT(nv->v_idx % 32);
 		}
 	}

drivers/net/ethernet/meta/fbnic/fbnic_txrx.h

@@ -110,8 +110,6 @@ struct fbnic_napi_vector {
 	u8 txt_count;
 	u8 rxt_count;
 
-	struct list_head napis;
-
 	struct fbnic_q_triad qt[];
 };
 
@@ -137,4 +135,9 @@ void fbnic_fill(struct fbnic_net *fbn);
 void fbnic_napi_depletion_check(struct net_device *netdev);
 int fbnic_wait_all_queues_idle(struct fbnic_dev *fbd, bool may_fail);
 
+static inline int fbnic_napi_idx(const struct fbnic_napi_vector *nv)
+{
+	return nv->v_idx - FBNIC_NON_NAPI_VECTORS;
+}
+
 #endif /* _FBNIC_TXRX_H_ */