[PATCH net] i40e: fix crash when Rx descriptor count is changed

[PATCH net] i40e: fix crash when Rx descriptor count is changed

[Björn Töpel]

From: Björn Töpel <bjorn.topel@intel.com>

When the AF_XDP buffer allocator was introduced, the Rx SW ring
"rx_bi" allocation was moved from i40e_setup_rx_descriptors()
function, and was instead done in the i40e_configure_rx_ring()
function.

This broke the ethtool set_ringparam() hook for changing the Rx
descriptor count, which was relying on i40e_setup_rx_descriptors() to
handle the alloction.

Fix this by adding an explicit i40e_alloc_rx_bi() call to
i40e_set_ringparam().

Fixes: be1222b585fd ("i40e: Separate kernel allocated rx_bi rings from AF_XDP rings")
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
---
 drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index aa8026b1eb81..67806b7b2f49 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -2070,6 +2070,9 @@ static int i40e_set_ringparam(struct net_device *netdev,
 			 */
 			rx_rings[i].tail = hw->hw_addr + I40E_PRTGEN_STATUS;
 			err = i40e_setup_rx_descriptors(&rx_rings[i]);
+			if (err)
+				goto rx_unwind;
+			err = i40e_alloc_rx_bi(&rx_rings[i]);
 			if (err)
 				goto rx_unwind;
 

base-commit: 18dbd4cd9b8c957025cf90a3c50102b31bde14f7
-- 
2.25.1

RE: [Intel-wired-lan] [PATCH net] i40e: fix crash when Rx descriptor count is changed

[Bowers, AndrewX]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Björn Töpel
> Sent: Friday, June 12, 2020 4:48 AM
> To: intel-wired-lan@lists.osuosl.org
> Cc: netdev@vger.kernel.org; bpf@vger.kernel.org; Topel, Bjorn
> <bjorn.topel@intel.com>; Karlsson, Magnus <magnus.karlsson@intel.com>
> Subject: [Intel-wired-lan] [PATCH net] i40e: fix crash when Rx descriptor
> count is changed
> 
> From: Björn Töpel <bjorn.topel@intel.com>
> 
> When the AF_XDP buffer allocator was introduced, the Rx SW ring "rx_bi"
> allocation was moved from i40e_setup_rx_descriptors() function, and was
> instead done in the i40e_configure_rx_ring() function.
> 
> This broke the ethtool set_ringparam() hook for changing the Rx descriptor
> count, which was relying on i40e_setup_rx_descriptors() to handle the
> alloction.
> 
> Fix this by adding an explicit i40e_alloc_rx_bi() call to i40e_set_ringparam().
> 
> Fixes: be1222b585fd ("i40e: Separate kernel allocated rx_bi rings from
> AF_XDP rings")
> Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
> ---
>  drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 3 +++
>  1 file changed, 3 insertions(+)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>