bnxt_en: Synchronize tx when xdp redirects happen on same ring

If there are more CPUs than the number of TX XDP rings, multiple XDP
redirects can select the same TX ring based on the CPU on which
XDP redirect is called.  Add locking when needed and use static
key to decide whether to take the lock.

Fixes: 0323aa29d818 ("bnxt_en: optimized XDP_REDIRECT support")
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 1c28495875cfcaf1ff8968ca60f460cdf1fd2f8a..874fad0a5cf8fbc78876a14ce0d3b5e952416d69 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -3253,6 +3253,7 @@ static int bnxt_alloc_tx_rings(struct bnxt *bp)
                }
                qidx = bp->tc_to_qidx[j];
                ring->queue_id = bp->q_info[qidx].queue_id;
+               spin_lock_init(&txr->xdp_tx_lock);
                if (i < bp->tx_nr_rings_xdp)
                        continue;
                if (i % bp->tx_nr_rings_per_tc == (bp->tx_nr_rings_per_tc - 1))
@@ -10338,6 +10339,12 @@ static int __bnxt_open_nic(struct bnxt *bp, bool irq_re_init, bool link_re_init)
        if (irq_re_init)
                udp_tunnel_nic_reset_ntf(bp->dev);
 
+       if (bp->tx_nr_rings_xdp < num_possible_cpus()) {
+               if (!static_key_enabled(&bnxt_xdp_locking_key))
+                       static_branch_enable(&bnxt_xdp_locking_key);
+       } else if (static_key_enabled(&bnxt_xdp_locking_key)) {
+               static_branch_disable(&bnxt_xdp_locking_key);
+       }
        set_bit(BNXT_STATE_OPEN, &bp->state);
        bnxt_enable_int(bp);
        /* Enable TX queues */

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 61aa3e8c59527469df1c2f72544e5d122e1b24a3..b4d3d051463b681d6d840b484272cd4f0f860ac4 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -800,6 +800,8 @@ struct bnxt_tx_ring_info {
        u32                     dev_state;
 
        struct bnxt_ring_struct tx_ring_struct;
+       /* Synchronize simultaneous xdp_xmit on same ring */
+       spinlock_t              xdp_tx_lock;
 };
 
 #define BNXT_LEGACY_COAL_CMPL_PARAMS                                   \

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
index 52fad0fdeacf31d3cd6fbb15e0106b9721e18eeb..c0541ff00ac882f826aa467b6314f989d3a05f81 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
@@ -20,6 +20,8 @@
 #include "bnxt.h"
 #include "bnxt_xdp.h"
 
+DEFINE_STATIC_KEY_FALSE(bnxt_xdp_locking_key);
+
 struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
                                   struct bnxt_tx_ring_info *txr,
                                   dma_addr_t mapping, u32 len)
@@ -227,6 +229,9 @@ int bnxt_xdp_xmit(struct net_device *dev, int num_frames,
        ring = smp_processor_id() % bp->tx_nr_rings_xdp;
        txr = &bp->tx_ring[ring];
 
+       if (static_branch_unlikely(&bnxt_xdp_locking_key))
+               spin_lock(&txr->xdp_tx_lock);
+
        for (i = 0; i < num_frames; i++) {
                struct xdp_frame *xdp = frames[i];
 
@@ -250,6 +255,9 @@ int bnxt_xdp_xmit(struct net_device *dev, int num_frames,
                bnxt_db_write(bp, &txr->tx_db, txr->tx_prod);
        }
 
+       if (static_branch_unlikely(&bnxt_xdp_locking_key))
+               spin_unlock(&txr->xdp_tx_lock);
+
        return nxmit;
 }
 

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
index 0df40c3beb05024b68116679b6194173f73e1524..067bb5e821f542bbc24e51cd7f303667f1a8ade5 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h
@@ -10,6 +10,8 @@
 #ifndef BNXT_XDP_H
 #define BNXT_XDP_H
 
+DECLARE_STATIC_KEY_FALSE(bnxt_xdp_locking_key);
+
 struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
                                   struct bnxt_tx_ring_info *txr,
                                   dma_addr_t mapping, u32 len);