bnxt_en: Fix memory corruption when FW resources change during ifdown

bnxt_set_dflt_rings() assumes that it is always called before any TC has
been created.  So it doesn't take bp->num_tc into account and assumes
that it is always 0 or 1.

In the FW resource or capability change scenario, the FW will return
flags in bnxt_hwrm_if_change() that will cause the driver to
reinitialize and call bnxt_cancel_reservations().  This will lead to
bnxt_init_dflt_ring_mode() calling bnxt_set_dflt_rings() and bp->num_tc
may be greater than 1.  This will cause bp->tx_ring[] to be sized too
small and cause memory corruption in bnxt_alloc_cp_rings().

Fix it by properly scaling the TX rings by bp->num_tc in the code
paths mentioned above.  Add 2 helper functions to determine
bp->tx_nr_rings and bp->tx_nr_rings_per_tc.

Fixes: ec5d31e3c15d ("bnxt_en: Handle firmware reset status during IF_UP.")
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20250825175927.459987-2-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 207a8bb36ae5f44b7a5f5d2d1d3cdbec32d19504..1f5c06f1296b28e8f294bc02ccacf06bf72e5ead 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -12851,6 +12851,17 @@ static int bnxt_set_xps_mapping(struct bnxt *bp)
        return rc;
 }
 
+static int bnxt_tx_nr_rings(struct bnxt *bp)
+{
+       return bp->num_tc ? bp->tx_nr_rings_per_tc * bp->num_tc :
+                           bp->tx_nr_rings_per_tc;
+}
+
+static int bnxt_tx_nr_rings_per_tc(struct bnxt *bp)
+{
+       return bp->num_tc ? bp->tx_nr_rings / bp->num_tc : bp->tx_nr_rings;
+}
+
 static int __bnxt_open_nic(struct bnxt *bp, bool irq_re_init, bool link_re_init)
 {
        int rc = 0;
@@ -16325,7 +16336,7 @@ static void bnxt_trim_dflt_sh_rings(struct bnxt *bp)
        bp->cp_nr_rings = min_t(int, bp->tx_nr_rings_per_tc, bp->rx_nr_rings);
        bp->rx_nr_rings = bp->cp_nr_rings;
        bp->tx_nr_rings_per_tc = bp->cp_nr_rings;
-       bp->tx_nr_rings = bp->tx_nr_rings_per_tc;
+       bp->tx_nr_rings = bnxt_tx_nr_rings(bp);
 }
 
 static int bnxt_set_dflt_rings(struct bnxt *bp, bool sh)
@@ -16357,7 +16368,7 @@ static int bnxt_set_dflt_rings(struct bnxt *bp, bool sh)
                bnxt_trim_dflt_sh_rings(bp);
        else
                bp->cp_nr_rings = bp->tx_nr_rings_per_tc + bp->rx_nr_rings;
-       bp->tx_nr_rings = bp->tx_nr_rings_per_tc;
+       bp->tx_nr_rings = bnxt_tx_nr_rings(bp);
 
        avail_msix = bnxt_get_max_func_irqs(bp) - bp->cp_nr_rings;
        if (avail_msix >= BNXT_MIN_ROCE_CP_RINGS) {
@@ -16370,7 +16381,7 @@ static int bnxt_set_dflt_rings(struct bnxt *bp, bool sh)
        rc = __bnxt_reserve_rings(bp);
        if (rc && rc != -ENODEV)
                netdev_warn(bp->dev, "Unable to reserve tx rings\n");
-       bp->tx_nr_rings_per_tc = bp->tx_nr_rings;
+       bp->tx_nr_rings_per_tc = bnxt_tx_nr_rings_per_tc(bp);
        if (sh)
                bnxt_trim_dflt_sh_rings(bp);
 
@@ -16379,7 +16390,7 @@ static int bnxt_set_dflt_rings(struct bnxt *bp, bool sh)
                rc = __bnxt_reserve_rings(bp);
                if (rc && rc != -ENODEV)
                        netdev_warn(bp->dev, "2nd rings reservation failed.\n");
-               bp->tx_nr_rings_per_tc = bp->tx_nr_rings;
+               bp->tx_nr_rings_per_tc = bnxt_tx_nr_rings_per_tc(bp);
        }
        if (BNXT_CHIP_TYPE_NITRO_A0(bp)) {
                bp->rx_nr_rings++;
@@ -16413,7 +16424,7 @@ static int bnxt_init_dflt_ring_mode(struct bnxt *bp)
        if (rc)
                goto init_dflt_ring_err;
 
-       bp->tx_nr_rings_per_tc = bp->tx_nr_rings;
+       bp->tx_nr_rings_per_tc = bnxt_tx_nr_rings_per_tc(bp);
 
        bnxt_set_dflt_rfs(bp);