Commit ccba9f6b authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Paolo Abeni
Browse files

net: update NAPI threaded config even for disabled NAPIs 



We have to make sure that all future NAPIs will have the right threaded
state when the state is configured on the device level.
We chose not to have an "unset" state for threaded, and not to wipe
the NAPI config clean when channels are explicitly disabled.
This means the persistent config structs "exist" even when their NAPIs
are not instantiated.

Differently put - the NAPI persistent state lives in the net_device
(ncfg == struct napi_config):

    ,--- [napi 0] - [napi 1]
 [dev]      |          |
    `--- [ncfg 0] - [ncfg 1]

so say we a device with 2 queues but only 1 enabled:

    ,--- [napi 0]
 [dev]      |
    `--- [ncfg 0] - [ncfg 1]

now we set the device to threaded=1:

    ,---------- [napi 0 (thr:1)]
 [dev(thr:1)]      |
    `---------- [ncfg 0 (thr:1)] - [ncfg 1 (thr:?)]

Since [ncfg 1] was not attached to a NAPI during configuration we
skipped it. If we create a NAPI for it later it will have the old
setting (presumably disabled). One could argue if this is right
or not "in principle", but it's definitely not how things worked
before per-NAPI config..

Fixes: 2677010e ("Add support to set NAPI threaded for individual NAPI")
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarJoe Damato <joe@dama.to>
Link: https://patch.msgid.link/20250809001205.1147153-3-kuba@kernel.org


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent bda053d6

include/linux/netdevice.h

+4 −1
Original line number Diff line number Diff line
@@ -2071,6 +2071,8 @@ enum netdev_reg_state { 
 *	@max_pacing_offload_horizon: max EDT offload horizon in nsec.

 *	@napi_config: An array of napi_config structures containing per-NAPI

 *		      settings.

 *	@num_napi_configs:	number of allocated NAPI config structs,

 *		always >= max(num_rx_queues, num_tx_queues).

 *	@gro_flush_timeout:	timeout for GRO layer in NAPI

 *	@napi_defer_hard_irqs:	If not zero, provides a counter that would

 *				allow to avoid NIC hard IRQ, on busy queues.
@@ -2482,8 +2484,9 @@ struct net_device { 


	u64			max_pacing_offload_horizon;

	struct napi_config	*napi_config;

	unsigned long		gro_flush_timeout;

	u32			num_napi_configs;

	u32			napi_defer_hard_irqs;

	unsigned long		gro_flush_timeout;



	/**

	 * @up: copy of @state's IFF_UP, but safe to read with just @lock.

net/core/dev.c

+6 −1
Original line number Diff line number Diff line
@@ -6999,7 +6999,7 @@ int netif_set_threaded(struct net_device *dev, 
		       enum netdev_napi_threaded threaded)

{

	struct napi_struct *napi;

	int err = 0;

	int i, err = 0;



	netdev_assert_locked_or_invisible(dev);
@@ -7021,6 +7021,10 @@ int netif_set_threaded(struct net_device *dev, 
	list_for_each_entry(napi, &dev->napi_list, dev_list)

		WARN_ON_ONCE(napi_set_threaded(napi, threaded));



	/* Override the config for all NAPIs even if currently not listed */

	for (i = 0; i < dev->num_napi_configs; i++)

		dev->napi_config[i].threaded = threaded;



	return err;

}
@@ -11873,6 +11877,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name, 
		goto free_all;

	dev->cfg_pending = dev->cfg;



	dev->num_napi_configs = maxqs;

	napi_config_sz = array_size(maxqs, sizeof(*dev->napi_config));

	dev->napi_config = kvzalloc(napi_config_sz, GFP_KERNEL_ACCOUNT);

	if (!dev->napi_config)