bnxt_en: implement netdev_queue_mgmt_ops

Implement netdev_queue_mgmt_ops for bnxt added in [1].

Two bnxt_rx_ring_info structs are allocated to hold the new/old queue
memory. Queue memory is copied from/to the main bp->rx_ring[idx]
bnxt_rx_ring_info.

Queue memory is pre-allocated in bnxt_queue_mem_alloc() into a clone,
and then copied into bp->rx_ring[idx] in bnxt_queue_mem_start().

Similarly, when bp->rx_ring[idx] is stopped its queue memory is copied
into a clone, and then freed later in bnxt_queue_mem_free().

I tested this patchset with netdev_rx_queue_restart(), including
inducing errors in all places that returns an error code. In all cases,
the queue is left in a good working state.

Rx queues are created/destroyed using bnxt_hwrm_rx_ring_alloc() and
bnxt_hwrm_rx_ring_free(), which issue HWRM_RING_ALLOC and HWRM_RING_FREE
commands respectively to the firmware. By the time a HWRM_RING_FREE
response is received, there won't be any more completions from that
queue.

Thanks to Somnath for helping me with this patch. With their permission
I've added them as Acked-by.

[1]: https://lore.kernel.org/netdev/20240501232549.1327174-2-shailend@google.com/Acked-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -3996,6 +3996,62 @@ static int bnxt_alloc_cp_rings(struct bnxt *bp)
 	return 0;
 }
 
+static void bnxt_init_rx_ring_struct(struct bnxt *bp,
+				     struct bnxt_rx_ring_info *rxr)
+{
+	struct bnxt_ring_mem_info *rmem;
+	struct bnxt_ring_struct *ring;
+
+	ring = &rxr->rx_ring_struct;
+	rmem = &ring->ring_mem;
+	rmem->nr_pages = bp->rx_nr_pages;
+	rmem->page_size = HW_RXBD_RING_SIZE;
+	rmem->pg_arr = (void **)rxr->rx_desc_ring;
+	rmem->dma_arr = rxr->rx_desc_mapping;
+	rmem->vmem_size = SW_RXBD_RING_SIZE * bp->rx_nr_pages;
+	rmem->vmem = (void **)&rxr->rx_buf_ring;
+
+	ring = &rxr->rx_agg_ring_struct;
+	rmem = &ring->ring_mem;
+	rmem->nr_pages = bp->rx_agg_nr_pages;
+	rmem->page_size = HW_RXBD_RING_SIZE;
+	rmem->pg_arr = (void **)rxr->rx_agg_desc_ring;
+	rmem->dma_arr = rxr->rx_agg_desc_mapping;
+	rmem->vmem_size = SW_RXBD_AGG_RING_SIZE * bp->rx_agg_nr_pages;
+	rmem->vmem = (void **)&rxr->rx_agg_ring;
+}
+
+static void bnxt_reset_rx_ring_struct(struct bnxt *bp,
+				      struct bnxt_rx_ring_info *rxr)
+{
+	struct bnxt_ring_mem_info *rmem;
+	struct bnxt_ring_struct *ring;
+	int i;
+
+	rxr->page_pool->p.napi = NULL;
+	rxr->page_pool = NULL;
+
+	ring = &rxr->rx_ring_struct;
+	rmem = &ring->ring_mem;
+	rmem->pg_tbl = NULL;
+	rmem->pg_tbl_map = 0;
+	for (i = 0; i < rmem->nr_pages; i++) {
+		rmem->pg_arr[i] = NULL;
+		rmem->dma_arr[i] = 0;
+	}
+	*rmem->vmem = NULL;
+
+	ring = &rxr->rx_agg_ring_struct;
+	rmem = &ring->ring_mem;
+	rmem->pg_tbl = NULL;
+	rmem->pg_tbl_map = 0;
+	for (i = 0; i < rmem->nr_pages; i++) {
+		rmem->pg_arr[i] = NULL;
+		rmem->dma_arr[i] = 0;
+	}
+	*rmem->vmem = NULL;
+}
+
 static void bnxt_init_ring_struct(struct bnxt *bp)
 {
 	int i, j;
@@ -14914,6 +14970,224 @@ static const struct netdev_stat_ops bnxt_stat_ops = {
 	.get_base_stats		= bnxt_get_base_stats,
 };
 
+static int bnxt_alloc_rx_agg_bmap(struct bnxt *bp, struct bnxt_rx_ring_info *rxr)
+{
+	u16 mem_size;
+
+	rxr->rx_agg_bmap_size = bp->rx_agg_ring_mask + 1;
+	mem_size = rxr->rx_agg_bmap_size / 8;
+	rxr->rx_agg_bmap = kzalloc(mem_size, GFP_KERNEL);
+	if (!rxr->rx_agg_bmap)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int bnxt_queue_mem_alloc(struct net_device *dev, void *qmem, int idx)
+{
+	struct bnxt_rx_ring_info *rxr, *clone;
+	struct bnxt *bp = netdev_priv(dev);
+	struct bnxt_ring_struct *ring;
+	int rc;
+
+	rxr = &bp->rx_ring[idx];
+	clone = qmem;
+	memcpy(clone, rxr, sizeof(*rxr));
+	bnxt_init_rx_ring_struct(bp, clone);
+	bnxt_reset_rx_ring_struct(bp, clone);
+
+	clone->rx_prod = 0;
+	clone->rx_agg_prod = 0;
+	clone->rx_sw_agg_prod = 0;
+	clone->rx_next_cons = 0;
+
+	rc = bnxt_alloc_rx_page_pool(bp, clone, rxr->page_pool->p.nid);
+	if (rc)
+		return rc;
+
+	ring = &clone->rx_ring_struct;
+	rc = bnxt_alloc_ring(bp, &ring->ring_mem);
+	if (rc)
+		goto err_free_rx_ring;
+
+	if (bp->flags & BNXT_FLAG_AGG_RINGS) {
+		ring = &clone->rx_agg_ring_struct;
+		rc = bnxt_alloc_ring(bp, &ring->ring_mem);
+		if (rc)
+			goto err_free_rx_agg_ring;
+
+		rc = bnxt_alloc_rx_agg_bmap(bp, clone);
+		if (rc)
+			goto err_free_rx_agg_ring;
+	}
+
+	bnxt_init_one_rx_ring_rxbd(bp, clone);
+	bnxt_init_one_rx_agg_ring_rxbd(bp, clone);
+
+	bnxt_alloc_one_rx_ring_skb(bp, clone, idx);
+	if (bp->flags & BNXT_FLAG_AGG_RINGS)
+		bnxt_alloc_one_rx_ring_page(bp, clone, idx);
+
+	return 0;
+
+err_free_rx_agg_ring:
+	bnxt_free_ring(bp, &clone->rx_agg_ring_struct.ring_mem);
+err_free_rx_ring:
+	bnxt_free_ring(bp, &clone->rx_ring_struct.ring_mem);
+	clone->page_pool->p.napi = NULL;
+	page_pool_destroy(clone->page_pool);
+	clone->page_pool = NULL;
+	return rc;
+}
+
+static void bnxt_queue_mem_free(struct net_device *dev, void *qmem)
+{
+	struct bnxt_rx_ring_info *rxr = qmem;
+	struct bnxt *bp = netdev_priv(dev);
+	struct bnxt_ring_struct *ring;
+
+	bnxt_free_one_rx_ring(bp, rxr);
+	bnxt_free_one_rx_agg_ring(bp, rxr);
+
+	/* At this point, this NAPI instance has another page pool associated
+	 * with it. Disconnect here before freeing the old page pool to avoid
+	 * warnings.
+	 */
+	rxr->page_pool->p.napi = NULL;
+	page_pool_destroy(rxr->page_pool);
+	rxr->page_pool = NULL;
+
+	ring = &rxr->rx_ring_struct;
+	bnxt_free_ring(bp, &ring->ring_mem);
+
+	ring = &rxr->rx_agg_ring_struct;
+	bnxt_free_ring(bp, &ring->ring_mem);
+
+	kfree(rxr->rx_agg_bmap);
+	rxr->rx_agg_bmap = NULL;
+}
+
+static void bnxt_copy_rx_ring(struct bnxt *bp,
+			      struct bnxt_rx_ring_info *dst,
+			      struct bnxt_rx_ring_info *src)
+{
+	struct bnxt_ring_mem_info *dst_rmem, *src_rmem;
+	struct bnxt_ring_struct *dst_ring, *src_ring;
+	int i;
+
+	dst_ring = &dst->rx_ring_struct;
+	dst_rmem = &dst_ring->ring_mem;
+	src_ring = &src->rx_ring_struct;
+	src_rmem = &src_ring->ring_mem;
+
+	WARN_ON(dst_rmem->nr_pages != src_rmem->nr_pages);
+	WARN_ON(dst_rmem->page_size != src_rmem->page_size);
+	WARN_ON(dst_rmem->flags != src_rmem->flags);
+	WARN_ON(dst_rmem->depth != src_rmem->depth);
+	WARN_ON(dst_rmem->vmem_size != src_rmem->vmem_size);
+	WARN_ON(dst_rmem->ctx_mem != src_rmem->ctx_mem);
+
+	dst_rmem->pg_tbl = src_rmem->pg_tbl;
+	dst_rmem->pg_tbl_map = src_rmem->pg_tbl_map;
+	*dst_rmem->vmem = *src_rmem->vmem;
+	for (i = 0; i < dst_rmem->nr_pages; i++) {
+		dst_rmem->pg_arr[i] = src_rmem->pg_arr[i];
+		dst_rmem->dma_arr[i] = src_rmem->dma_arr[i];
+	}
+
+	if (!(bp->flags & BNXT_FLAG_AGG_RINGS))
+		return;
+
+	dst_ring = &dst->rx_agg_ring_struct;
+	dst_rmem = &dst_ring->ring_mem;
+	src_ring = &src->rx_agg_ring_struct;
+	src_rmem = &src_ring->ring_mem;
+
+	WARN_ON(dst_rmem->nr_pages != src_rmem->nr_pages);
+	WARN_ON(dst_rmem->page_size != src_rmem->page_size);
+	WARN_ON(dst_rmem->flags != src_rmem->flags);
+	WARN_ON(dst_rmem->depth != src_rmem->depth);
+	WARN_ON(dst_rmem->vmem_size != src_rmem->vmem_size);
+	WARN_ON(dst_rmem->ctx_mem != src_rmem->ctx_mem);
+	WARN_ON(dst->rx_agg_bmap_size != src->rx_agg_bmap_size);
+
+	dst_rmem->pg_tbl = src_rmem->pg_tbl;
+	dst_rmem->pg_tbl_map = src_rmem->pg_tbl_map;
+	*dst_rmem->vmem = *src_rmem->vmem;
+	for (i = 0; i < dst_rmem->nr_pages; i++) {
+		dst_rmem->pg_arr[i] = src_rmem->pg_arr[i];
+		dst_rmem->dma_arr[i] = src_rmem->dma_arr[i];
+	}
+
+	dst->rx_agg_bmap = src->rx_agg_bmap;
+}
+
+static int bnxt_queue_start(struct net_device *dev, void *qmem, int idx)
+{
+	struct bnxt *bp = netdev_priv(dev);
+	struct bnxt_rx_ring_info *rxr, *clone;
+	struct bnxt_cp_ring_info *cpr;
+	int rc;
+
+	rxr = &bp->rx_ring[idx];
+	clone = qmem;
+
+	rxr->rx_prod = clone->rx_prod;
+	rxr->rx_agg_prod = clone->rx_agg_prod;
+	rxr->rx_sw_agg_prod = clone->rx_sw_agg_prod;
+	rxr->rx_next_cons = clone->rx_next_cons;
+	rxr->page_pool = clone->page_pool;
+
+	bnxt_copy_rx_ring(bp, rxr, clone);
+
+	rc = bnxt_hwrm_rx_ring_alloc(bp, rxr);
+	if (rc)
+		return rc;
+	rc = bnxt_hwrm_rx_agg_ring_alloc(bp, rxr);
+	if (rc)
+		goto err_free_hwrm_rx_ring;
+
+	bnxt_db_write(bp, &rxr->rx_db, rxr->rx_prod);
+	if (bp->flags & BNXT_FLAG_AGG_RINGS)
+		bnxt_db_write(bp, &rxr->rx_agg_db, rxr->rx_agg_prod);
+
+	napi_enable(&rxr->bnapi->napi);
+
+	cpr = &rxr->bnapi->cp_ring;
+	cpr->sw_stats->rx.rx_resets++;
+
+	return 0;
+
+err_free_hwrm_rx_ring:
+	bnxt_hwrm_rx_ring_free(bp, rxr, false);
+	return rc;
+}
+
+static int bnxt_queue_stop(struct net_device *dev, void *qmem, int idx)
+{
+	struct bnxt *bp = netdev_priv(dev);
+	struct bnxt_rx_ring_info *rxr;
+
+	rxr = &bp->rx_ring[idx];
+	napi_disable(&rxr->bnapi->napi);
+	bnxt_hwrm_rx_ring_free(bp, rxr, false);
+	bnxt_hwrm_rx_agg_ring_free(bp, rxr, false);
+	rxr->rx_next_cons = 0;
+
+	memcpy(qmem, rxr, sizeof(*rxr));
+	bnxt_init_rx_ring_struct(bp, qmem);
+
+	return 0;
+}
+
+static const struct netdev_queue_mgmt_ops bnxt_queue_mgmt_ops = {
+	.ndo_queue_mem_size	= sizeof(struct bnxt_rx_ring_info),
+	.ndo_queue_mem_alloc	= bnxt_queue_mem_alloc,
+	.ndo_queue_mem_free	= bnxt_queue_mem_free,
+	.ndo_queue_start	= bnxt_queue_start,
+	.ndo_queue_stop		= bnxt_queue_stop,
+};
+
 static void bnxt_remove_one(struct pci_dev *pdev)
 {
 	struct net_device *dev = pci_get_drvdata(pdev);
@@ -15379,6 +15653,7 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	dev->stat_ops = &bnxt_stat_ops;
 	dev->watchdog_timeo = BNXT_TX_TIMEOUT;
 	dev->ethtool_ops = &bnxt_ethtool_ops;
+	dev->queue_mgmt_ops = &bnxt_queue_mgmt_ops;
 	pci_set_drvdata(pdev, dev);
 
 	rc = bnxt_alloc_hwrm_resources(bp);