bnxt_en: Fix trimming of P5 RX and TX rings

The recent commit to trim the RX and TX rings on P5 chips by assigning
each with max CP rings divided by 2 is not correct.  Max CP rings
divided by 2 may be bigger than the original RX or TX and would
lead to failure.  In other words, we may be checking for increased
RX/TX rings than required and it may fail.

Fix it by calling __bnxt_trim_rings() instead that would properly
trim RX and TX without the possibility of increasing their values.

Fixes: f5b29c6afe36 ("bnxt_en: Add helper to get the number of CP rings required for TX rings")
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20231212005122.2401-2-michael.chan@broadcom.com
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 92a54113f8724230213014ceee8bc6c111b1ba61..7afbbc71f92fc5ccd1cff0d3920cb39b49b96f0c 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -6489,6 +6489,8 @@ static void bnxt_hwrm_ring_free(struct bnxt *bp, bool close_path)
        }
 }
 
+static int __bnxt_trim_rings(struct bnxt *bp, int *rx, int *tx, int max,
+                            bool shared);
 static int bnxt_trim_rings(struct bnxt *bp, int *rx, int *tx, int max,
                           bool shared);
 
@@ -6532,8 +6534,9 @@ static int bnxt_hwrm_get_rings(struct bnxt *bp)
                        if (bp->flags & BNXT_FLAG_AGG_RINGS)
                                rx >>= 1;
                        if (cp < (rx + tx)) {
-                               rx = cp / 2;
-                               tx = rx;
+                               rc = __bnxt_trim_rings(bp, &rx, &tx, cp, false);
+                               if (rc)
+                                       return rc;
                                if (bp->flags & BNXT_FLAG_AGG_RINGS)
                                        rx <<= 1;
                                hw_resc->resv_rx_rings = rx;
@@ -13885,9 +13888,12 @@ static void _bnxt_get_max_rings(struct bnxt *bp, int *max_rx, int *max_tx,
        if (bp->flags & BNXT_FLAG_AGG_RINGS)
                *max_rx >>= 1;
        if (bp->flags & BNXT_FLAG_CHIP_P5_PLUS) {
-               if (*max_cp < (*max_rx + *max_tx)) {
-                       *max_rx = *max_cp / 2;
-                       *max_tx = *max_rx;
+               int rc;
+
+               rc = __bnxt_trim_rings(bp, max_rx, max_tx, *max_cp, false);
+               if (rc) {
+                       *max_rx = 0;
+                       *max_tx = 0;
                }
                /* On P5 chips, max_cp output param should be available NQs */
                *max_cp = max_irq;