[PATCH net] bnxt_en: Fix the resource check condition for RSS contexts

[PATCH net] bnxt_en: Fix the resource check condition for RSS contexts

[Michael Chan]

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From: Pavan Chebbi <pavan.chebbi@broadcom.com>

While creating a new RSS context, bnxt_rfs_capable() currently
makes a strict check to see if the required VNICs are already
available.  If the current VNICs are not what is required,
either too many or not enough, it will call the firmware to
reserve the exact number required.

There is a bug in the firmware when the driver tries to
relinquish some reserved VNICs and RSS contexts.  It will
cause the default VNIC to lose its RSS configuration and
cause receive packets to be placed incorrectly.

Workaround this problem by skipping the resource reduction.
The driver will not reduce the VNIC and RSS context reservations
when a context is deleted.  The resources will be available for
use when new contexts are created later.

Potentially, this workaround can cause us to run out of VNIC
and RSS contexts if there are a lot of VF functions creating
and deleting RSS contexts.  In the future, we will conditionally
disable this workaround when the firmware fix is available.

Fixes: 438ba39b25fe ("bnxt_en: Improve RSS context reservation infrastructure")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/netdev/20240625010210.2002310-1-kuba@kernel.org/
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index a6d69a45fa01..53085058100c 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -12669,7 +12669,11 @@ bool bnxt_rfs_capable(struct bnxt *bp, bool new_rss_ctx)
 	if (!BNXT_NEW_RM(bp))
 		return true;
 
-	if (hwr.vnic == bp->hw_resc.resv_vnics &&
+	/* Do not reduce VNIC and RSS ctx reservations.  There is a FW
+	 * issue that will mess up the default VNIC if we reduce the
+	 * reservations.
+	 */
+	if (hwr.vnic <= bp->hw_resc.resv_vnics &&
 	    hwr.rss_ctx <= bp->hw_resc.resv_rsscos_ctxs)
 		return true;
 
-- 
2.30.1


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Re: [PATCH net] bnxt_en: Fix the resource check condition for RSS contexts

[Simon Horman]

On Wed, Jul 03, 2024 at 11:01:12AM -0700, Michael Chan wrote:
> From: Pavan Chebbi <pavan.chebbi@broadcom.com>
> 
> While creating a new RSS context, bnxt_rfs_capable() currently
> makes a strict check to see if the required VNICs are already
> available.  If the current VNICs are not what is required,
> either too many or not enough, it will call the firmware to
> reserve the exact number required.
> 
> There is a bug in the firmware when the driver tries to
> relinquish some reserved VNICs and RSS contexts.  It will
> cause the default VNIC to lose its RSS configuration and
> cause receive packets to be placed incorrectly.
> 
> Workaround this problem by skipping the resource reduction.
> The driver will not reduce the VNIC and RSS context reservations
> when a context is deleted.  The resources will be available for
> use when new contexts are created later.
> 
> Potentially, this workaround can cause us to run out of VNIC
> and RSS contexts if there are a lot of VF functions creating
> and deleting RSS contexts.  In the future, we will conditionally
> disable this workaround when the firmware fix is available.
> 
> Fixes: 438ba39b25fe ("bnxt_en: Improve RSS context reservation infrastructure")
> Reported-by: Jakub Kicinski <kuba@kernel.org>
> Link: https://lore.kernel.org/netdev/20240625010210.2002310-1-kuba@kernel.org/
> Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
> Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
> Signed-off-by: Michael Chan <michael.chan@broadcom.com>

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net] bnxt_en: Fix the resource check condition for RSS contexts

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed,  3 Jul 2024 11:01:12 -0700 you wrote:
> From: Pavan Chebbi <pavan.chebbi@broadcom.com>
> 
> While creating a new RSS context, bnxt_rfs_capable() currently
> makes a strict check to see if the required VNICs are already
> available.  If the current VNICs are not what is required,
> either too many or not enough, it will call the firmware to
> reserve the exact number required.
> 
> [...]

Here is the summary with links:
  - [net] bnxt_en: Fix the resource check condition for RSS contexts
    https://git.kernel.org/netdev/net/c/5d350dc3429b

You are awesome, thank you!
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