[PATCH net-next v5 3/6] net: let pp memory provider to specify rx buf len

[Pavel Begunkov <asml.silence@gmail.com>]

Allow memory providers to configure rx queues with a specific receive
buffer length. Pass it in struct pp_memory_provider_params, which is
copied into the queue, so it's preserved across queue restarts. It's an
opt-in feature for drivers, which they can enable by setting
NDO_QUEUE_RX_BUF_SIZE to their struct netdev_queue_mgmt_ops.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 include/net/netdev_queues.h   | 9 +++++++++
 include/net/page_pool/types.h | 1 +
 net/core/netdev_rx_queue.c    | 4 ++++
 3 files changed, 14 insertions(+)

diff --git a/include/net/netdev_queues.h b/include/net/netdev_queues.h
index cd00e0406cf4..2e6bcec1e1e3 100644
--- a/include/net/netdev_queues.h
+++ b/include/net/netdev_queues.h
@@ -111,6 +111,11 @@ void netdev_stat_queue_sum(struct net_device *netdev,
 			   int tx_start, int tx_end,
 			   struct netdev_queue_stats_tx *tx_sum);
 
+enum {
+	/* queue restart support custom rx buffer sizes */
+	NDO_QUEUE_RX_BUF_SIZE		= 0x1,
+};
+
 /**
  * struct netdev_queue_mgmt_ops - netdev ops for queue management
  *
@@ -130,6 +135,8 @@ void netdev_stat_queue_sum(struct net_device *netdev,
  * @ndo_queue_get_dma_dev: Get dma device for zero-copy operations to be used
  *			   for this queue. Return NULL on error.
  *
+ * @supported_params: bitmask of supported features, see NDO_QUEUE_*
+ *
  * Note that @ndo_queue_mem_alloc and @ndo_queue_mem_free may be called while
  * the interface is closed. @ndo_queue_start and @ndo_queue_stop will only
  * be called for an interface which is open.
@@ -149,6 +156,8 @@ struct netdev_queue_mgmt_ops {
 						  int idx);
 	struct device *		(*ndo_queue_get_dma_dev)(struct net_device *dev,
 							 int idx);
+
+	unsigned supported_params;
 };
 
 bool netif_rxq_has_unreadable_mp(struct net_device *dev, int idx);
diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index 1509a536cb85..be74e4aec7b5 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h
@@ -161,6 +161,7 @@ struct memory_provider_ops;
 struct pp_memory_provider_params {
 	void *mp_priv;
 	const struct memory_provider_ops *mp_ops;
+	u32 rx_buf_len;
 };
 
 struct page_pool {
diff --git a/net/core/netdev_rx_queue.c b/net/core/netdev_rx_queue.c
index a0083f176a9c..09d6f97e910e 100644
--- a/net/core/netdev_rx_queue.c
+++ b/net/core/netdev_rx_queue.c
@@ -29,6 +29,10 @@ int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx)
 	    !qops->ndo_queue_mem_alloc || !qops->ndo_queue_start)
 		return -EOPNOTSUPP;
 
+	if (!(qops->supported_params & NDO_QUEUE_RX_BUF_SIZE) &&
+	    rxq->mp_params.rx_buf_len)
+		return -EOPNOTSUPP;
+
 	netdev_assert_locked(dev);
 
 	new_mem = kvzalloc(qops->ndo_queue_mem_size, GFP_KERNEL);
-- 
2.49.0