gve: Remove qpl_cfg struct since qpl_ids map with queues respectively

The qpl_cfg struct was used to make sure that no two different queues
are using QPL with the same qpl_id. We can remove that qpl_cfg struct
since now the qpl_ids map with the queues respectively as follows:
For tx queues: qpl_id = tx_qid
For rx queues: qpl_id = max_tx_queues + rx_qid

And when XDP is used, it will need the user to reduce the tx queues to
be at most half of the max_tx_queues. Then it will use the same number
of tx queues starting from the end of existing tx queues for XDP. So the
XDP queues will not exceed the max_tx_queues range and will not overlap
with the rx queues, where the qpl_ids will not have overlapping too.

Considering of that, we remove the qpl_cfg struct to get the qpl_id
directly based on the queue id. Unless we are erroneously allocating a
rx/tx queue that has already been allocated, we would never allocate
the qpl with the same qpl_id twice. In that case, it should fail much
earlier than the QPL assignment.

Suggested-by: Praveen Kaligineedi <pkaligineedi@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
Reviewed-by: Shailend Chand <shailend@google.com>
Link: https://lore.kernel.org/r/20240417205757.778551-1-ziweixiao@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

7 files changed, 20 insertions, 113 deletions

diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h
index e97633b68e25..53b5244dc7bc 100644
--- a/drivers/net/ethernet/google/gve/gve.h
+++ b/drivers/net/ethernet/google/gve/gve.h
@@ -639,7 +639,6 @@ struct gve_ptype_lut {
 
 /* Parameters for allocating queue page lists */
 struct gve_qpls_alloc_cfg {
-	struct gve_qpl_config *qpl_cfg;
 	struct gve_queue_config *tx_cfg;
 	struct gve_queue_config *rx_cfg;
 
@@ -655,9 +654,8 @@ struct gve_qpls_alloc_cfg {
 struct gve_tx_alloc_rings_cfg {
 	struct gve_queue_config *qcfg;
 
-	/* qpls and qpl_cfg must already be allocated */
+	/* qpls must already be allocated */
 	struct gve_queue_page_list *qpls;
-	struct gve_qpl_config *qpl_cfg;
 
 	u16 ring_size;
 	u16 start_idx;
@@ -674,9 +672,8 @@ struct gve_rx_alloc_rings_cfg {
 	struct gve_queue_config *qcfg;
 	struct gve_queue_config *qcfg_tx;
 
-	/* qpls and qpl_cfg must already be allocated */
+	/* qpls must already be allocated */
 	struct gve_queue_page_list *qpls;
-	struct gve_qpl_config *qpl_cfg;
 
 	u16 ring_size;
 	u16 packet_buffer_size;
@@ -732,7 +729,6 @@ struct gve_priv {
 	u16 num_xdp_queues;
 	struct gve_queue_config tx_cfg;
 	struct gve_queue_config rx_cfg;
-	struct gve_qpl_config qpl_cfg; /* map used QPL ids */
 	u32 num_ntfy_blks; /* spilt between TX and RX so must be even */
 
 	struct gve_registers __iomem *reg_bar0; /* see gve_register.h */
@@ -1053,37 +1049,6 @@ static inline u32 gve_get_rx_pages_per_qpl_dqo(u32 rx_desc_cnt)
 	return 2 * rx_desc_cnt;
 }
 
-/* Returns a pointer to the next available tx qpl in the list of qpls */
-static inline
-struct gve_queue_page_list *gve_assign_tx_qpl(struct gve_tx_alloc_rings_cfg *cfg,
-					      int tx_qid)
-{
-	/* QPL already in use */
-	if (test_bit(tx_qid, cfg->qpl_cfg->qpl_id_map))
-		return NULL;
-	set_bit(tx_qid, cfg->qpl_cfg->qpl_id_map);
-	return &cfg->qpls[tx_qid];
-}
-
-/* Returns a pointer to the next available rx qpl in the list of qpls */
-static inline
-struct gve_queue_page_list *gve_assign_rx_qpl(struct gve_rx_alloc_rings_cfg *cfg,
-					      int rx_qid)
-{
-	int id = gve_get_rx_qpl_id(cfg->qcfg_tx, rx_qid);
-	/* QPL already in use */
-	if (test_bit(id, cfg->qpl_cfg->qpl_id_map))
-		return NULL;
-	set_bit(id, cfg->qpl_cfg->qpl_id_map);
-	return &cfg->qpls[id];
-}
-
-/* Unassigns the qpl with the given id */
-static inline void gve_unassign_qpl(struct gve_qpl_config *qpl_cfg, int id)
-{
-	clear_bit(id, qpl_cfg->qpl_id_map);
-}
-
 /* Returns the correct dma direction for tx and rx qpls */
 static inline enum dma_data_direction gve_qpl_dma_dir(struct gve_priv *priv,
 						      int id)
diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c
index 299206d15c73..bd7632eed776 100644
--- a/drivers/net/ethernet/google/gve/gve_ethtool.c
+++ b/drivers/net/ethernet/google/gve/gve_ethtool.c
@@ -510,7 +510,6 @@ static int gve_adjust_ring_sizes(struct gve_priv *priv,
 	struct gve_tx_alloc_rings_cfg tx_alloc_cfg = {0};
 	struct gve_rx_alloc_rings_cfg rx_alloc_cfg = {0};
 	struct gve_qpls_alloc_cfg qpls_alloc_cfg = {0};
-	struct gve_qpl_config new_qpl_cfg;
 	int err;
 
 	/* get current queue configuration */
@@ -521,14 +520,6 @@ static int gve_adjust_ring_sizes(struct gve_priv *priv,
 	tx_alloc_cfg.ring_size = new_tx_desc_cnt;
 	rx_alloc_cfg.ring_size = new_rx_desc_cnt;
 
-	/* qpl_cfg is not read-only, it contains a map that gets updated as
-	 * rings are allocated, which is why we cannot use the yet unreleased
-	 * one in priv.
-	 */
-	qpls_alloc_cfg.qpl_cfg = &new_qpl_cfg;
-	tx_alloc_cfg.qpl_cfg = &new_qpl_cfg;
-	rx_alloc_cfg.qpl_cfg = &new_qpl_cfg;
-
 	if (netif_running(priv->dev)) {
 		err = gve_adjust_config(priv, &qpls_alloc_cfg,
 					&tx_alloc_cfg, &rx_alloc_cfg);
diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c
index a515e5af843c..61039e3dd2bb 100644
--- a/drivers/net/ethernet/google/gve/gve_main.c
+++ b/drivers/net/ethernet/google/gve/gve_main.c
@@ -829,7 +829,6 @@ static void gve_tx_get_curr_alloc_cfg(struct gve_priv *priv,
 	cfg->qcfg = &priv->tx_cfg;
 	cfg->raw_addressing = !gve_is_qpl(priv);
 	cfg->qpls = priv->qpls;
-	cfg->qpl_cfg = &priv->qpl_cfg;
 	cfg->ring_size = priv->tx_desc_cnt;
 	cfg->start_idx = 0;
 	cfg->num_rings = gve_num_tx_queues(priv);
@@ -1119,22 +1118,13 @@ static int gve_alloc_qpls(struct gve_priv *priv, struct gve_qpls_alloc_cfg *cfg,
 	if (!qpls)
 		return -ENOMEM;
 
-	cfg->qpl_cfg->qpl_map_size = BITS_TO_LONGS(max_queues) *
-		sizeof(unsigned long) * BITS_PER_BYTE;
-	cfg->qpl_cfg->qpl_id_map = kvcalloc(BITS_TO_LONGS(max_queues),
-					    sizeof(unsigned long), GFP_KERNEL);
-	if (!cfg->qpl_cfg->qpl_id_map) {
-		err = -ENOMEM;
-		goto free_qpl_array;
-	}
-
 	/* Allocate TX QPLs */
 	page_count = priv->tx_pages_per_qpl;
 	tx_num_qpls = gve_num_tx_qpls(cfg->tx_cfg, cfg->num_xdp_queues,
 				      gve_is_qpl(priv));
 	err = gve_alloc_n_qpls(priv, qpls, page_count, 0, tx_num_qpls);
 	if (err)
-		goto free_qpl_map;
+		goto free_qpl_array;
 
 	/* Allocate RX QPLs */
 	rx_start_id = gve_rx_start_qpl_id(cfg->tx_cfg);
@@ -1157,9 +1147,6 @@ static int gve_alloc_qpls(struct gve_priv *priv, struct gve_qpls_alloc_cfg *cfg,
 
 free_tx_qpls:
 	gve_free_n_qpls(priv, qpls, 0, tx_num_qpls);
-free_qpl_map:
-	kvfree(cfg->qpl_cfg->qpl_id_map);
-	cfg->qpl_cfg->qpl_id_map = NULL;
 free_qpl_array:
 	kvfree(qpls);
 	return err;
@@ -1175,9 +1162,6 @@ static void gve_free_qpls(struct gve_priv *priv,
 	if (!qpls)
 		return;
 
-	kvfree(cfg->qpl_cfg->qpl_id_map);
-	cfg->qpl_cfg->qpl_id_map = NULL;
-
 	for (i = 0; i < max_queues; i++)
 		gve_free_queue_page_list(priv, &qpls[i], i);
 
@@ -1292,7 +1276,6 @@ static void gve_qpls_get_curr_alloc_cfg(struct gve_priv *priv,
 	  cfg->raw_addressing = !gve_is_qpl(priv);
 	  cfg->is_gqi = gve_is_gqi(priv);
 	  cfg->num_xdp_queues = priv->num_xdp_queues;
-	  cfg->qpl_cfg = &priv->qpl_cfg;
 	  cfg->tx_cfg = &priv->tx_cfg;
 	  cfg->rx_cfg = &priv->rx_cfg;
 	  cfg->qpls = priv->qpls;
@@ -1306,7 +1289,6 @@ static void gve_rx_get_curr_alloc_cfg(struct gve_priv *priv,
 	cfg->raw_addressing = !gve_is_qpl(priv);
 	cfg->enable_header_split = priv->header_split_enabled;
 	cfg->qpls = priv->qpls;
-	cfg->qpl_cfg = &priv->qpl_cfg;
 	cfg->ring_size = priv->rx_desc_cnt;
 	cfg->packet_buffer_size = gve_is_gqi(priv) ?
 				  GVE_DEFAULT_RX_BUFFER_SIZE :
@@ -1419,7 +1401,6 @@ static int gve_queues_start(struct gve_priv *priv,
 	priv->rx = rx_alloc_cfg->rx;
 
 	/* Record new configs into priv */
-	priv->qpl_cfg = *qpls_alloc_cfg->qpl_cfg;
 	priv->tx_cfg = *tx_alloc_cfg->qcfg;
 	priv->rx_cfg = *rx_alloc_cfg->qcfg;
 	priv->tx_desc_cnt = tx_alloc_cfg->ring_size;
@@ -1916,20 +1897,11 @@ int gve_adjust_queues(struct gve_priv *priv,
 	struct gve_tx_alloc_rings_cfg tx_alloc_cfg = {0};
 	struct gve_rx_alloc_rings_cfg rx_alloc_cfg = {0};
 	struct gve_qpls_alloc_cfg qpls_alloc_cfg = {0};
-	struct gve_qpl_config new_qpl_cfg;
 	int err;
 
 	gve_get_curr_alloc_cfgs(priv, &qpls_alloc_cfg,
 				&tx_alloc_cfg, &rx_alloc_cfg);
 
-	/* qpl_cfg is not read-only, it contains a map that gets updated as
-	 * rings are allocated, which is why we cannot use the yet unreleased
-	 * one in priv.
-	 */
-	qpls_alloc_cfg.qpl_cfg = &new_qpl_cfg;
-	tx_alloc_cfg.qpl_cfg = &new_qpl_cfg;
-	rx_alloc_cfg.qpl_cfg = &new_qpl_cfg;
-
 	/* Relay the new config from ethtool */
 	qpls_alloc_cfg.tx_cfg = &new_tx_config;
 	tx_alloc_cfg.qcfg = &new_tx_config;
@@ -2121,18 +2093,10 @@ static int gve_set_features(struct net_device *netdev,
 	struct gve_rx_alloc_rings_cfg rx_alloc_cfg = {0};
 	struct gve_qpls_alloc_cfg qpls_alloc_cfg = {0};
 	struct gve_priv *priv = netdev_priv(netdev);
-	struct gve_qpl_config new_qpl_cfg;
 	int err;
 
 	gve_get_curr_alloc_cfgs(priv, &qpls_alloc_cfg,
 				&tx_alloc_cfg, &rx_alloc_cfg);
-	/* qpl_cfg is not read-only, it contains a map that gets updated as
-	 * rings are allocated, which is why we cannot use the yet unreleased
-	 * one in priv.
-	 */
-	qpls_alloc_cfg.qpl_cfg = &new_qpl_cfg;
-	tx_alloc_cfg.qpl_cfg = &new_qpl_cfg;
-	rx_alloc_cfg.qpl_cfg = &new_qpl_cfg;
 
 	if ((netdev->features & NETIF_F_LRO) != (features & NETIF_F_LRO)) {
 		netdev->features ^= NETIF_F_LRO;
diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c
index cd727e55ae0f..9b56e89c4f43 100644
--- a/drivers/net/ethernet/google/gve/gve_rx.c
+++ b/drivers/net/ethernet/google/gve/gve_rx.c
@@ -38,7 +38,6 @@ static void gve_rx_unfill_pages(struct gve_priv *priv,
 		for (i = 0; i < slots; i++)
 			page_ref_sub(rx->data.page_info[i].page,
 				     rx->data.page_info[i].pagecnt_bias - 1);
-		gve_unassign_qpl(cfg->qpl_cfg, rx->data.qpl->id);
 		rx->data.qpl = NULL;
 
 		for (i = 0; i < rx->qpl_copy_pool_mask + 1; i++) {
@@ -145,13 +144,11 @@ static int gve_rx_prefill_pages(struct gve_rx_ring *rx,
 		return -ENOMEM;
 
 	if (!rx->data.raw_addressing) {
-		rx->data.qpl = gve_assign_rx_qpl(cfg, rx->q_num);
-		if (!rx->data.qpl) {
-			kvfree(rx->data.page_info);
-			rx->data.page_info = NULL;
-			return -ENOMEM;
-		}
+		u32 qpl_id = gve_get_rx_qpl_id(cfg->qcfg_tx, rx->q_num);
+
+		rx->data.qpl = &cfg->qpls[qpl_id];
 	}
+
 	for (i = 0; i < slots; i++) {
 		if (!rx->data.raw_addressing) {
 			struct page *page = rx->data.qpl->pages[i];
@@ -204,7 +201,6 @@ alloc_err_qpl:
 		page_ref_sub(rx->data.page_info[i].page,
 			     rx->data.page_info[i].pagecnt_bias - 1);
 
-	gve_unassign_qpl(cfg->qpl_cfg, rx->data.qpl->id);
 	rx->data.qpl = NULL;
 
 	return err;
diff --git a/drivers/net/ethernet/google/gve/gve_rx_dqo.c b/drivers/net/ethernet/google/gve/gve_rx_dqo.c
index 15108407b54f..53fd2d87233f 100644
--- a/drivers/net/ethernet/google/gve/gve_rx_dqo.c
+++ b/drivers/net/ethernet/google/gve/gve_rx_dqo.c
@@ -247,10 +247,8 @@ static void gve_rx_free_ring_dqo(struct gve_priv *priv, struct gve_rx_ring *rx,
 		if (bs->page_info.page)
 			gve_free_page_dqo(priv, bs, !rx->dqo.qpl);
 	}
-	if (rx->dqo.qpl) {
-		gve_unassign_qpl(cfg->qpl_cfg, rx->dqo.qpl->id);
-		rx->dqo.qpl = NULL;
-	}
+
+	rx->dqo.qpl = NULL;
 
 	if (rx->dqo.bufq.desc_ring) {
 		size = sizeof(rx->dqo.bufq.desc_ring[0]) * buffer_queue_slots;
@@ -359,9 +357,9 @@ static int gve_rx_alloc_ring_dqo(struct gve_priv *priv,
 		goto err;
 
 	if (!cfg->raw_addressing) {
-		rx->dqo.qpl = gve_assign_rx_qpl(cfg, rx->q_num);
-		if (!rx->dqo.qpl)
-			goto err;
+		u32 qpl_id = gve_get_rx_qpl_id(cfg->qcfg_tx, rx->q_num);
+
+		rx->dqo.qpl = &cfg->qpls[qpl_id];
 		rx->dqo.next_qpl_page_idx = 0;
 	}
 
diff --git a/drivers/net/ethernet/google/gve/gve_tx.c b/drivers/net/ethernet/google/gve/gve_tx.c
index 4b9853adc113..f805700d67e7 100644
--- a/drivers/net/ethernet/google/gve/gve_tx.c
+++ b/drivers/net/ethernet/google/gve/gve_tx.c
@@ -225,7 +225,6 @@ static void gve_tx_free_ring_gqi(struct gve_priv *priv, struct gve_tx_ring *tx,
 
 	if (!tx->raw_addressing) {
 		gve_tx_fifo_release(priv, &tx->tx_fifo);
-		gve_unassign_qpl(cfg->qpl_cfg, tx->tx_fifo.qpl->id);
 		tx->tx_fifo.qpl = NULL;
 	}
 
@@ -280,12 +279,12 @@ static int gve_tx_alloc_ring_gqi(struct gve_priv *priv,
 	tx->raw_addressing = cfg->raw_addressing;
 	tx->dev = hdev;
 	if (!tx->raw_addressing) {
-		tx->tx_fifo.qpl = gve_assign_tx_qpl(cfg, idx);
-		if (!tx->tx_fifo.qpl)
-			goto abort_with_desc;
+		u32 qpl_id = gve_tx_qpl_id(priv, tx->q_num);
+
+		tx->tx_fifo.qpl = &cfg->qpls[qpl_id];
 		/* map Tx FIFO */
 		if (gve_tx_fifo_init(priv, &tx->tx_fifo))
-			goto abort_with_qpl;
+			goto abort_with_desc;
 	}
 
 	tx->q_resources =
@@ -301,9 +300,6 @@ static int gve_tx_alloc_ring_gqi(struct gve_priv *priv,
 abort_with_fifo:
 	if (!tx->raw_addressing)
 		gve_tx_fifo_release(priv, &tx->tx_fifo);
-abort_with_qpl:
-	if (!tx->raw_addressing)
-		gve_unassign_qpl(cfg->qpl_cfg, tx->tx_fifo.qpl->id);
 abort_with_desc:
 	dma_free_coherent(hdev, bytes, tx->desc, tx->bus);
 	tx->desc = NULL;
diff --git a/drivers/net/ethernet/google/gve/gve_tx_dqo.c b/drivers/net/ethernet/google/gve/gve_tx_dqo.c
index 70f29b90a982..3d825e406c4b 100644
--- a/drivers/net/ethernet/google/gve/gve_tx_dqo.c
+++ b/drivers/net/ethernet/google/gve/gve_tx_dqo.c
@@ -236,10 +236,7 @@ static void gve_tx_free_ring_dqo(struct gve_priv *priv, struct gve_tx_ring *tx,
 	kvfree(tx->dqo.tx_qpl_buf_next);
 	tx->dqo.tx_qpl_buf_next = NULL;
 
-	if (tx->dqo.qpl) {
-		gve_unassign_qpl(cfg->qpl_cfg, tx->dqo.qpl->id);
-		tx->dqo.qpl = NULL;
-	}
+	tx->dqo.qpl = NULL;
 
 	netif_dbg(priv, drv, priv->dev, "freed tx queue %d\n", idx);
 }
@@ -352,9 +349,9 @@ static int gve_tx_alloc_ring_dqo(struct gve_priv *priv,
 		goto err;
 
 	if (!cfg->raw_addressing) {
-		tx->dqo.qpl = gve_assign_tx_qpl(cfg, idx);
-		if (!tx->dqo.qpl)
-			goto err;
+		u32 qpl_id = gve_tx_qpl_id(priv, tx->q_num);
+
+		tx->dqo.qpl = &cfg->qpls[qpl_id];
 
 		if (gve_tx_qpl_buf_init(tx))
 			goto err;