From: Íñigo Huguet ihuguet@redhat.com
[ Upstream commit e84a1e1e683f3558e30f437d7c99df35afb8b52c ]
In systems without MSI-X capabilities, xdp_txq_queues_mode is calculated in efx_allocate_msix_channels, but when enabling MSI-X fails, it was not changed to a proper default value. This was leading to the driver thinking that it has dedicated XDP queues, when it didn't.
Fix it by setting xdp_txq_queues_mode to the correct value if the driver fallbacks to MSI or legacy IRQ mode. The correct value is EFX_XDP_TX_QUEUES_BORROWED because there are no XDP dedicated queues.
The issue can be easily visible if the kernel is started with pci=nomsi, then a call trace is shown. It is not shown only with sfc's modparam interrupt_mode=2. Call trace example: WARNING: CPU: 2 PID: 663 at drivers/net/ethernet/sfc/efx_channels.c:828 efx_set_xdp_channels+0x124/0x260 [sfc] [...skip...] Call Trace: <TASK> efx_set_channels+0x5c/0xc0 [sfc] efx_probe_nic+0x9b/0x15a [sfc] efx_probe_all+0x10/0x1a2 [sfc] efx_pci_probe_main+0x12/0x156 [sfc] efx_pci_probe_post_io+0x18/0x103 [sfc] efx_pci_probe.cold+0x154/0x257 [sfc] local_pci_probe+0x42/0x80
Fixes: 6215b608a8c4 ("sfc: last resort fallback for lack of xdp tx queues") Reported-by: Yanghang Liu yanghliu@redhat.com Signed-off-by: Íñigo Huguet ihuguet@redhat.com Acked-by: Martin Habets habetsm.xilinx@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/sfc/efx_channels.c | 2 ++ drivers/net/ethernet/sfc/siena/efx_channels.c | 2 ++ 2 files changed, 4 insertions(+)
diff --git a/drivers/net/ethernet/sfc/efx_channels.c b/drivers/net/ethernet/sfc/efx_channels.c index fcea3ea809d77..41b33a75333cd 100644 --- a/drivers/net/ethernet/sfc/efx_channels.c +++ b/drivers/net/ethernet/sfc/efx_channels.c @@ -301,6 +301,7 @@ int efx_probe_interrupts(struct efx_nic *efx) efx->tx_channel_offset = 0; efx->n_xdp_channels = 0; efx->xdp_channel_offset = efx->n_channels; + efx->xdp_txq_queues_mode = EFX_XDP_TX_QUEUES_BORROWED; rc = pci_enable_msi(efx->pci_dev); if (rc == 0) { efx_get_channel(efx, 0)->irq = efx->pci_dev->irq; @@ -322,6 +323,7 @@ int efx_probe_interrupts(struct efx_nic *efx) efx->tx_channel_offset = efx_separate_tx_channels ? 1 : 0; efx->n_xdp_channels = 0; efx->xdp_channel_offset = efx->n_channels; + efx->xdp_txq_queues_mode = EFX_XDP_TX_QUEUES_BORROWED; efx->legacy_irq = efx->pci_dev->irq; }
diff --git a/drivers/net/ethernet/sfc/siena/efx_channels.c b/drivers/net/ethernet/sfc/siena/efx_channels.c index 06ed74994e366..1776f7f8a7a90 100644 --- a/drivers/net/ethernet/sfc/siena/efx_channels.c +++ b/drivers/net/ethernet/sfc/siena/efx_channels.c @@ -302,6 +302,7 @@ int efx_siena_probe_interrupts(struct efx_nic *efx) efx->tx_channel_offset = 0; efx->n_xdp_channels = 0; efx->xdp_channel_offset = efx->n_channels; + efx->xdp_txq_queues_mode = EFX_XDP_TX_QUEUES_BORROWED; rc = pci_enable_msi(efx->pci_dev); if (rc == 0) { efx_get_channel(efx, 0)->irq = efx->pci_dev->irq; @@ -323,6 +324,7 @@ int efx_siena_probe_interrupts(struct efx_nic *efx) efx->tx_channel_offset = efx_siena_separate_tx_channels ? 1 : 0; efx->n_xdp_channels = 0; efx->xdp_channel_offset = efx->n_channels; + efx->xdp_txq_queues_mode = EFX_XDP_TX_QUEUES_BORROWED; efx->legacy_irq = efx->pci_dev->irq; }