Commit 37b61cda authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

bnxt: don't handle XDP in netpoll 



Similarly to other recently fixed drivers make sure we don't
try to access XDP or page pool APIs when NAPI budget is 0.
NAPI budget of 0 may mean that we are in netpoll.

This may result in running software IRQs in hard IRQ context,
leading to deadlocks or crashes.

To make sure bnapi->tx_pkts don't get wiped without handling
the events, move clearing the field into the handler itself.
Remember to clear tx_pkts after reset (bnxt_enable_napi())
as it's technically possible that netpoll will accumulate
some tx_pkts and then a reset will happen, leaving tx_pkts
out of sync with reality.

Fixes: 322b87ca ("bnxt_en: add page_pool support")
Reviewed-by: default avatarAndy Gospodarek <gospo@broadcom.com>
Reviewed-by: default avatarMichael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20230728205020.2784844-1-kuba@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 4b31fd4d

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

+15 −11
Original line number Diff line number Diff line
@@ -633,12 +633,13 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	return NETDEV_TX_OK;

}



static void bnxt_tx_int(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts)

static void bnxt_tx_int(struct bnxt *bp, struct bnxt_napi *bnapi, int budget)

{

	struct bnxt_tx_ring_info *txr = bnapi->tx_ring;

	struct netdev_queue *txq = netdev_get_tx_queue(bp->dev, txr->txq_index);

	u16 cons = txr->tx_cons;

	struct pci_dev *pdev = bp->pdev;

	int nr_pkts = bnapi->tx_pkts;

	int i;

	unsigned int tx_bytes = 0;
@@ -688,6 +689,7 @@ static void bnxt_tx_int(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts) 
		dev_kfree_skb_any(skb);

	}



	bnapi->tx_pkts = 0;

	WRITE_ONCE(txr->tx_cons, cons);



	__netif_txq_completed_wake(txq, nr_pkts, tx_bytes,
@@ -2569,12 +2571,11 @@ static int __bnxt_poll_work(struct bnxt *bp, struct bnxt_cp_ring_info *cpr, 
	return rx_pkts;

}



static void __bnxt_poll_work_done(struct bnxt *bp, struct bnxt_napi *bnapi)

static void __bnxt_poll_work_done(struct bnxt *bp, struct bnxt_napi *bnapi,

				  int budget)

{

	if (bnapi->tx_pkts) {

		bnapi->tx_int(bp, bnapi, bnapi->tx_pkts);

		bnapi->tx_pkts = 0;

	}

	if (bnapi->tx_pkts)

		bnapi->tx_int(bp, bnapi, budget);



	if ((bnapi->events & BNXT_RX_EVENT) && !(bnapi->in_reset)) {

		struct bnxt_rx_ring_info *rxr = bnapi->rx_ring;
@@ -2603,7 +2604,7 @@ static int bnxt_poll_work(struct bnxt *bp, struct bnxt_cp_ring_info *cpr, 
	 */

	bnxt_db_cq(bp, &cpr->cp_db, cpr->cp_raw_cons);



	__bnxt_poll_work_done(bp, bnapi);

	__bnxt_poll_work_done(bp, bnapi, budget);

	return rx_pkts;

}
@@ -2734,7 +2735,7 @@ static int __bnxt_poll_cqs(struct bnxt *bp, struct bnxt_napi *bnapi, int budget) 
}



static void __bnxt_poll_cqs_done(struct bnxt *bp, struct bnxt_napi *bnapi,

				 u64 dbr_type)

				 u64 dbr_type, int budget)

{

	struct bnxt_cp_ring_info *cpr = &bnapi->cp_ring;

	int i;
@@ -2750,7 +2751,7 @@ static void __bnxt_poll_cqs_done(struct bnxt *bp, struct bnxt_napi *bnapi, 
			cpr2->had_work_done = 0;

		}

	}

	__bnxt_poll_work_done(bp, bnapi);

	__bnxt_poll_work_done(bp, bnapi, budget);

}



static int bnxt_poll_p5(struct napi_struct *napi, int budget)
@@ -2780,7 +2781,8 @@ static int bnxt_poll_p5(struct napi_struct *napi, int budget) 
			if (cpr->has_more_work)

				break;



			__bnxt_poll_cqs_done(bp, bnapi, DBR_TYPE_CQ_ARMALL);

			__bnxt_poll_cqs_done(bp, bnapi, DBR_TYPE_CQ_ARMALL,

					     budget);

			cpr->cp_raw_cons = raw_cons;

			if (napi_complete_done(napi, work_done))

				BNXT_DB_NQ_ARM_P5(&cpr->cp_db,
@@ -2810,7 +2812,7 @@ static int bnxt_poll_p5(struct napi_struct *napi, int budget) 
		}

		raw_cons = NEXT_RAW_CMP(raw_cons);

	}

	__bnxt_poll_cqs_done(bp, bnapi, DBR_TYPE_CQ);

	__bnxt_poll_cqs_done(bp, bnapi, DBR_TYPE_CQ, budget);

	if (raw_cons != cpr->cp_raw_cons) {

		cpr->cp_raw_cons = raw_cons;

		BNXT_DB_NQ_P5(&cpr->cp_db, raw_cons);
@@ -9429,6 +9431,8 @@ static void bnxt_enable_napi(struct bnxt *bp) 
			cpr->sw_stats.rx.rx_resets++;

		bnapi->in_reset = false;



		bnapi->tx_pkts = 0;



		if (bnapi->rx_ring) {

			INIT_WORK(&cpr->dim.work, bnxt_dim_work);

			cpr->dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE;

drivers/net/ethernet/broadcom/bnxt/bnxt.h

+1 −1
Original line number Diff line number Diff line
@@ -1005,7 +1005,7 @@ struct bnxt_napi { 
	struct bnxt_tx_ring_info	*tx_ring;



	void			(*tx_int)(struct bnxt *, struct bnxt_napi *,

					  int);

					  int budget);

	int			tx_pkts;

	u8			events;

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

+7 −1
Original line number Diff line number Diff line
@@ -125,16 +125,20 @@ static void __bnxt_xmit_xdp_redirect(struct bnxt *bp, 
	dma_unmap_len_set(tx_buf, len, 0);

}



void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts)

void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int budget)

{

	struct bnxt_tx_ring_info *txr = bnapi->tx_ring;

	struct bnxt_rx_ring_info *rxr = bnapi->rx_ring;

	bool rx_doorbell_needed = false;

	int nr_pkts = bnapi->tx_pkts;

	struct bnxt_sw_tx_bd *tx_buf;

	u16 tx_cons = txr->tx_cons;

	u16 last_tx_cons = tx_cons;

	int i, j, frags;



	if (!budget)

		return;



	for (i = 0; i < nr_pkts; i++) {

		tx_buf = &txr->tx_buf_ring[tx_cons];
@@ -161,6 +165,8 @@ void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts) 
		}

		tx_cons = NEXT_TX(tx_cons);

	}



	bnapi->tx_pkts = 0;

	WRITE_ONCE(txr->tx_cons, tx_cons);

	if (rx_doorbell_needed) {

		tx_buf = &txr->tx_buf_ring[last_tx_cons];

drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h

+1 −1
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp, 
				   struct bnxt_tx_ring_info *txr,

				   dma_addr_t mapping, u32 len,

				   struct xdp_buff *xdp);

void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts);

void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int budget);

bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,

		 struct xdp_buff xdp, struct page *page, u8 **data_ptr,

		 unsigned int *len, u8 *event);