| Message ID | 20240626180613.3190229-1-dave.jiang@intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: ntb_netdev: Move ntb_netdev_rx_handler() to call netif_rx() from __netif_rx() | expand |
On Wed, 26 Jun 2024 11:06:13 -0700 Dave Jiang wrote:
> Fixes: baebdf48c360 ("net: dev: Makes sure netif_rx() can be invoked in any context.")
Patch LGTM, but I think the Fixes tag needs to go back further.
Sebastian renamed and flipped semantics at the same time, so
what he did for this driver should be a noop.
IOW prior to his change netif_rx() expected to be called with
BH disabled, and the driver should have been using netif_rx_ni()
or netif_rx_any_context().
Maybe add this extra info to the commit message, there's also a way
to point out a dependency via a special tag..
But the Fixes tag should point to where the bug was introduced.
diff --git a/drivers/net/ntb_netdev.c b/drivers/net/ntb_netdev.c index 536bd6564f8b..dade51cf599c 100644 --- a/drivers/net/ntb_netdev.c +++ b/drivers/net/ntb_netdev.c @@ -119,7 +119,7 @@ static void ntb_netdev_rx_handler(struct ntb_transport_qp *qp, void *qp_data, skb->protocol = eth_type_trans(skb, ndev); skb->ip_summed = CHECKSUM_NONE; - if (__netif_rx(skb) == NET_RX_DROP) { + if (netif_rx(skb) == NET_RX_DROP) { ndev->stats.rx_errors++; ndev->stats.rx_dropped++; } else {
The following is emitted when using idxd (DSA) dmanegine as the data mover for ntb_transport that ntb_netdev uses. [74412.546922] BUG: using smp_processor_id() in preemptible [00000000] code: irq/52-idxd-por/14526 [74412.556784] caller is netif_rx_internal+0x42/0x130 [74412.562282] CPU: 6 PID: 14526 Comm: irq/52-idxd-por Not tainted 6.9.5 #5 [74412.569870] Hardware name: Intel Corporation ArcherCity/ArcherCity, BIOS EGSDCRB1.E9I.1752.P05.2402080856 02/08/2024 [74412.581699] Call Trace: [74412.584514] <TASK> [74412.586933] dump_stack_lvl+0x55/0x70 [74412.591129] check_preemption_disabled+0xc8/0xf0 [74412.596374] netif_rx_internal+0x42/0x130 [74412.600957] __netif_rx+0x20/0xd0 [74412.604743] ntb_netdev_rx_handler+0x66/0x150 [ntb_netdev] [74412.610985] ntb_complete_rxc+0xed/0x140 [ntb_transport] [74412.617010] ntb_rx_copy_callback+0x53/0x80 [ntb_transport] [74412.623332] idxd_dma_complete_txd+0xe3/0x160 [idxd] [74412.628963] idxd_wq_thread+0x1a6/0x2b0 [idxd] [74412.634046] irq_thread_fn+0x21/0x60 [74412.638134] ? irq_thread+0xa8/0x290 [74412.642218] irq_thread+0x1a0/0x290 [74412.646212] ? __pfx_irq_thread_fn+0x10/0x10 [74412.651071] ? __pfx_irq_thread_dtor+0x10/0x10 [74412.656117] ? __pfx_irq_thread+0x10/0x10 [74412.660686] kthread+0x100/0x130 [74412.664384] ? __pfx_kthread+0x10/0x10 [74412.668639] ret_from_fork+0x31/0x50 [74412.672716] ? __pfx_kthread+0x10/0x10 [74412.676978] ret_from_fork_asm+0x1a/0x30 [74412.681457] </TASK> The cause is due to the idxd driver interrupt completion handler uses threaded interrupt and the threaded handler is not hard or soft interrupt context. However __netif_rx() can only be called from interrupt context. Change the call to netif_rx() in order to allow completion via normal context for dmaengine drivers that utilize threaded irq handling. Fixes: baebdf48c360 ("net: dev: Makes sure netif_rx() can be invoked in any context.") Reported-by: Jerry Dai <jerry.dai@intel.com> Tested-by: Jerry Dai <jerry.dai@intel.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> --- drivers/net/ntb_netdev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)