eth: bnxt: fix counting packets discarded due to OOM and netpoll

I added OOM and netpoll discard counters, naively assuming that
the cpr pointer is pointing to a common completion ring.
Turns out that is usually *a* completion ring but not *the*
completion ring which bnapi->cp_ring points to. bnapi->cp_ring
is where the stats are read from, so we end up reporting 0
thru ethtool -S and qstat even though the drop events have happened.
Make 100% sure we're recording statistics in the correct structure.

Fixes: 907fd4a294db ("bnxt: count discards due to memory allocation errors")
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20240424002148.3937059-1-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 ed04a90a4fddec1ac4084bb2ac3cbd6655d43cb5..2c2ee79c4d77957761d8f3d9ca85bcecedd5fd0f 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -1778,7 +1778,7 @@ static inline struct sk_buff *bnxt_tpa_end(struct bnxt *bp,
                skb = bnxt_copy_skb(bnapi, data_ptr, len, mapping);
                if (!skb) {
                        bnxt_abort_tpa(cpr, idx, agg_bufs);
-                       cpr->sw_stats.rx.rx_oom_discards += 1;
+                       cpr->bnapi->cp_ring.sw_stats.rx.rx_oom_discards += 1;
                        return NULL;
                }
        } else {
@@ -1788,7 +1788,7 @@ static inline struct sk_buff *bnxt_tpa_end(struct bnxt *bp,
                new_data = __bnxt_alloc_rx_frag(bp, &new_mapping, GFP_ATOMIC);
                if (!new_data) {
                        bnxt_abort_tpa(cpr, idx, agg_bufs);
-                       cpr->sw_stats.rx.rx_oom_discards += 1;
+                       cpr->bnapi->cp_ring.sw_stats.rx.rx_oom_discards += 1;
                        return NULL;
                }
 
@@ -1804,7 +1804,7 @@ static inline struct sk_buff *bnxt_tpa_end(struct bnxt *bp,
                if (!skb) {
                        skb_free_frag(data);
                        bnxt_abort_tpa(cpr, idx, agg_bufs);
-                       cpr->sw_stats.rx.rx_oom_discards += 1;
+                       cpr->bnapi->cp_ring.sw_stats.rx.rx_oom_discards += 1;
                        return NULL;
                }
                skb_reserve(skb, bp->rx_offset);
@@ -1815,7 +1815,7 @@ static inline struct sk_buff *bnxt_tpa_end(struct bnxt *bp,
                skb = bnxt_rx_agg_pages_skb(bp, cpr, skb, idx, agg_bufs, true);
                if (!skb) {
                        /* Page reuse already handled by bnxt_rx_pages(). */
-                       cpr->sw_stats.rx.rx_oom_discards += 1;
+                       cpr->bnapi->cp_ring.sw_stats.rx.rx_oom_discards += 1;
                        return NULL;
                }
        }
@@ -2094,11 +2094,8 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
                        u32 frag_len = bnxt_rx_agg_pages_xdp(bp, cpr, &xdp,
                                                             cp_cons, agg_bufs,
                                                             false);
-                       if (!frag_len) {
-                               cpr->sw_stats.rx.rx_oom_discards += 1;
-                               rc = -ENOMEM;
-                               goto next_rx;
-                       }
+                       if (!frag_len)
+                               goto oom_next_rx;
                }
                xdp_active = true;
        }
@@ -2121,9 +2118,7 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
                                else
                                        bnxt_xdp_buff_frags_free(rxr, &xdp);
                        }
-                       cpr->sw_stats.rx.rx_oom_discards += 1;
-                       rc = -ENOMEM;
-                       goto next_rx;
+                       goto oom_next_rx;
                }
        } else {
                u32 payload;
@@ -2134,29 +2129,21 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
                        payload = 0;
                skb = bp->rx_skb_func(bp, rxr, cons, data, data_ptr, dma_addr,
                                      payload | len);
-               if (!skb) {
-                       cpr->sw_stats.rx.rx_oom_discards += 1;
-                       rc = -ENOMEM;
-                       goto next_rx;
-               }
+               if (!skb)
+                       goto oom_next_rx;
        }
 
        if (agg_bufs) {
                if (!xdp_active) {
                        skb = bnxt_rx_agg_pages_skb(bp, cpr, skb, cp_cons, agg_bufs, false);
-                       if (!skb) {
-                               cpr->sw_stats.rx.rx_oom_discards += 1;
-                               rc = -ENOMEM;
-                               goto next_rx;
-                       }
+                       if (!skb)
+                               goto oom_next_rx;
                } else {
                        skb = bnxt_xdp_build_skb(bp, skb, agg_bufs, rxr->page_pool, &xdp, rxcmp1);
                        if (!skb) {
                                /* we should be able to free the old skb here */
                                bnxt_xdp_buff_frags_free(rxr, &xdp);
-                               cpr->sw_stats.rx.rx_oom_discards += 1;
-                               rc = -ENOMEM;
-                               goto next_rx;
+                               goto oom_next_rx;
                        }
                }
        }
@@ -2234,6 +2221,11 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
        *raw_cons = tmp_raw_cons;
 
        return rc;
+
+oom_next_rx:
+       cpr->bnapi->cp_ring.sw_stats.rx.rx_oom_discards += 1;
+       rc = -ENOMEM;
+       goto next_rx;
 }
 
 /* In netpoll mode, if we are using a combined completion ring, we need to
@@ -2280,7 +2272,7 @@ static int bnxt_force_rx_discard(struct bnxt *bp,
        }
        rc = bnxt_rx_pkt(bp, cpr, raw_cons, event);
        if (rc && rc != -EBUSY)
-               cpr->sw_stats.rx.rx_netpoll_discards += 1;
+               cpr->bnapi->cp_ring.sw_stats.rx.rx_netpoll_discards += 1;
        return rc;
 }