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: 322b87ca55f2 ("bnxt_en: add page_pool support")
Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20230728205020.2784844-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index e5b54e6..06b238b 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -633,12 +633,13 @@ tx_kick_pending:
        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 @@ next_tx_int:
                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;

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 080e734..bb95c3d 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -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;
 

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
index 4efa5fe..7f2f9a3 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
@@ -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];

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
index ea430d6..5e412c5 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
@@ -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);