[PATCH net] bnxt_en: Fix mqprio and XDP ring checking logic

[PATCH net] bnxt_en: Fix mqprio and XDP ring checking logic

[Michael Chan]

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In bnxt_reserve_rings(), there is logic to check that the number of TX
rings reserved is enough to cover all the mqprio TCs, but it fails to
account for the TX XDP rings.  So the check will always fail if there
are mqprio TCs and TX XDP rings.  As a result, the driver always fails
to initialize after the XDP program is attached and the device will be
brought down.  A subsequent ifconfig up will also fail because the
number of TX rings is set to an inconsistent number.  Fix the check to
properly account for TX XDP rings.  If the check fails, set the number
of TX rings back to a consistent number after calling netdev_reset_tc().

Fixes: 674f50a5b026 ("bnxt_en: Implement new method to reserve rings.")
Reviewed-by: Hongguang Gao <hongguang.gao@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 240a7e8a7652..6c32f5c427b5 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -9274,10 +9274,14 @@ int bnxt_reserve_rings(struct bnxt *bp, bool irq_re_init)
 		netdev_err(bp->dev, "ring reservation/IRQ init failure rc: %d\n", rc);
 		return rc;
 	}
-	if (tcs && (bp->tx_nr_rings_per_tc * tcs != bp->tx_nr_rings)) {
+	if (tcs && (bp->tx_nr_rings_per_tc * tcs !=
+		    bp->tx_nr_rings - bp->tx_nr_rings_xdp)) {
 		netdev_err(bp->dev, "tx ring reservation failure\n");
 		netdev_reset_tc(bp->dev);
-		bp->tx_nr_rings_per_tc = bp->tx_nr_rings;
+		if (bp->tx_nr_rings_xdp)
+			bp->tx_nr_rings_per_tc = bp->tx_nr_rings_xdp;
+		else
+			bp->tx_nr_rings_per_tc = bp->tx_nr_rings;
 		return -ENOMEM;
 	}
 	return 0;
-- 
2.18.1


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Re: [PATCH net] bnxt_en: Fix mqprio and XDP ring checking logic

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Fri, 10 Feb 2023 12:31:55 -0500 you wrote:
> In bnxt_reserve_rings(), there is logic to check that the number of TX
> rings reserved is enough to cover all the mqprio TCs, but it fails to
> account for the TX XDP rings.  So the check will always fail if there
> are mqprio TCs and TX XDP rings.  As a result, the driver always fails
> to initialize after the XDP program is attached and the device will be
> brought down.  A subsequent ifconfig up will also fail because the
> number of TX rings is set to an inconsistent number.  Fix the check to
> properly account for TX XDP rings.  If the check fails, set the number
> of TX rings back to a consistent number after calling netdev_reset_tc().
> 
> [...]

Here is the summary with links:
  - [net] bnxt_en: Fix mqprio and XDP ring checking logic
    https://git.kernel.org/netdev/net/c/2038cc592811

You are awesome, thank you!
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