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net: replace IFF_KNOWSEPOCH with IFF_NEEDSEPOCH

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Expect that drivers call into the network stack with the net epoch
entered. This has already been the fact since early 2020. The net
interrupts, that are marked with INTR_TYPE_NET, were entering epoch
since 511d1afb6b. For the taskqueues there is NET_TASK_INIT() and
all drivers that were known back in 2020 we marked with it in
6c3e93cb5a. However in e87c494015 we took conservative approach
and preferred to opt-in rather than opt-out for the epoch.

This change not only reverts e87c494015 but adds a safety belt to
avoid panicing with INVARIANTS if there is a missed driver. With
INVARIANTS we will run in_epoch() check, print a warning and enter
the net epoch.  A driver that prints can be quickly fixed with the
IFF_NEEDSEPOCH flag, but better be augmented to properly enter the
epoch itself.

Note on TCP LRO: it is a backdoor to enter the TCP stack bypassing
some layers of net stack, ignoring either old IFF_KNOWSEPOCH or the
new IFF_NEEDSEPOCH.  But the tcp_lro_flush_all() asserts the presence
of network epoch.  Indeed, all NIC drivers that support LRO already
provide the epoch, either with help of INTR_TYPE_NET or just running
NET_EPOCH_ENTER() in their code.

Reviewed by:		zlei, gallatin, erj
Differential Revision:	https://reviews.freebsd.org/D39510
This commit is contained in:
Gleb Smirnoff 2023-04-17 09:08:35 -07:00
parent a540cdca31
commit a6b55ee6be
11 changed files with 59 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/compat/linux/linux_netlink.c
View File

@ -312,7 +312,7 @@ rtnl_if_flags_to_linux(unsigned int if_flags)
case IFF_ALLMULTI:
result |= flag;
break;
case IFF_KNOWSEPOCH:
case IFF_NEEDSEPOCH:
case IFF_DRV_OACTIVE:
case IFF_SIMPLEX:
case IFF_LINK0:

3
sys/dev/ena/ena.c
View File

@ -2393,8 +2393,7 @@ ena_setup_ifnet(device_t pdev, struct ena_adapter *adapter,
if_setdev(ifp, pdev);
if_setsoftc(ifp, adapter);
if_setflags(ifp,
IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST | IFF_KNOWSEPOCH);
if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
if_setinitfn(ifp, ena_init);
if_settransmitfn(ifp, ena_mq_start);
if_setqflushfn(ifp, ena_qflush);

3
sys/dev/mlx5/mlx5_en/mlx5_en_main.c
View File

@ -4526,8 +4526,7 @@ mlx5e_create_ifp(struct mlx5_core_dev *mdev)
if_initname(ifp, "mce", device_get_unit(mdev->pdev->dev.bsddev));
if_setmtu(ifp, ETHERMTU);
if_setinitfn(ifp, mlx5e_open);
if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST |
IFF_KNOWSEPOCH);
if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
if_setioctlfn(ifp, mlx5e_ioctl);
if_settransmitfn(ifp, mlx5e_xmit);
if_setqflushfn(ifp, if_qflush);

2
sys/dev/oce/oce_if.c
View File

@ -2111,7 +2111,7 @@ oce_attach_ifp(POCE_SOFTC sc)
ifmedia_add(&sc->media, IFM_ETHER | IFM_AUTO, 0, NULL);
ifmedia_set(&sc->media, IFM_ETHER | IFM_AUTO);
if_setflags(sc->ifp, IFF_BROADCAST | IFF_MULTICAST | IFF_KNOWSEPOCH);
if_setflags(sc->ifp, IFF_BROADCAST | IFF_MULTICAST);
if_setioctlfn(sc->ifp, oce_ioctl);
if_setstartfn(sc->ifp, oce_start);
if_setinitfn(sc->ifp, oce_init);

3
sys/dev/virtio/network/if_vtnet.c
View File

@ -1103,8 +1103,7 @@ vtnet_setup_interface(struct vtnet_softc *sc)
dev = sc->vtnet_dev;
ifp = sc->vtnet_ifp;
if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST |
IFF_KNOWSEPOCH);
if_setflags(ifp, IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST);
if_setbaudrate(ifp, IF_Gbps(10));
if_setinitfn(ifp, vtnet_init);
if_setioctlfn(ifp, vtnet_ioctl);

4
sys/net/if.h
View File

@ -144,7 +144,7 @@ struct if_data {
#define IFF_DEBUG 0x4 /* (n) turn on debugging */
#define IFF_LOOPBACK 0x8 /* (i) is a loopback net */
#define IFF_POINTOPOINT 0x10 /* (i) is a point-to-point link */
#define IFF_KNOWSEPOCH 0x20 /* (i) calls if_input in net epoch */
#define IFF_NEEDSEPOCH 0x20 /* (i) calls if_input w/o net epoch */
#define IFF_DRV_RUNNING 0x40 /* (d) resources allocated */
#define IFF_NOARP 0x80 /* (n) no address resolution protocol */
#define IFF_PROMISC 0x100 /* (n) receive all packets */
@ -179,7 +179,7 @@ struct if_data {
#define IFF_CANTCHANGE \
(IFF_BROADCAST|IFF_POINTOPOINT|IFF_DRV_RUNNING|IFF_DRV_OACTIVE|\
IFF_SIMPLEX|IFF_MULTICAST|IFF_ALLMULTI|IFF_PROMISC|\
IFF_DYING|IFF_CANTCONFIG|IFF_KNOWSEPOCH)
IFF_DYING|IFF_CANTCONFIG|IFF_NEEDSEPOCH)
/*
* Values for if_link_state.

1
sys/net/if_epair.c
View File

@ -543,7 +543,6 @@ epair_setup_ifp(struct epair_softc *sc, char *name, int unit)
ifp->if_dname = epairname;
ifp->if_dunit = unit;
ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST;
ifp->if_flags |= IFF_KNOWSEPOCH;
ifp->if_capabilities = IFCAP_VLAN_MTU;
ifp->if_capenable = IFCAP_VLAN_MTU;
ifp->if_transmit = epair_transmit;

25
sys/net/if_ethersubr.c
View File

@ -56,6 +56,9 @@
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/uuid.h>
#ifdef KDB
#include <sys/kdb.h>
#endif
#include <net/ieee_oui.h>
#include <net/if.h>
@ -813,7 +816,27 @@ ether_input(struct ifnet *ifp, struct mbuf *m)
struct mbuf *mn;
bool needs_epoch;
needs_epoch = !(ifp->if_flags & IFF_KNOWSEPOCH);
needs_epoch = (ifp->if_flags & IFF_NEEDSEPOCH);
#ifdef INVARIANTS
/*
* This temporary code is here to prevent epoch unaware and unmarked
* drivers to panic the system. Once all drivers are taken care of,
* the whole INVARIANTS block should go away.
*/
if (!needs_epoch && !in_epoch(net_epoch_preempt)) {
static bool printedonce;
needs_epoch = true;
if (!printedonce) {
printedonce = true;
if_printf(ifp, "called %s w/o net epoch! "
"PLEASE file a bug report.", __func__);
#ifdef KDB
kdb_backtrace();
#endif
}
}
#endif
/*
* The drivers are allowed to pass in a chain of packets linked with

26
sys/net/if_infiniband.c
View File

@ -25,6 +25,7 @@
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_kbd.h"
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
@ -38,6 +39,9 @@ __FBSDID("$FreeBSD$");
#include <sys/module.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#ifdef KDB
#include <sys/kdb.h>
#endif
#include <net/bpf.h>
#include <net/ethernet.h>
@ -417,7 +421,27 @@ infiniband_input(struct ifnet *ifp, struct mbuf *m)
int isr;
bool needs_epoch;
needs_epoch = (ifp->if_flags & IFF_KNOWSEPOCH) == 0;
needs_epoch = (ifp->if_flags & IFF_NEEDSEPOCH);
#ifdef INVARIANTS
/*
* This temporary code is here to prevent epoch unaware and unmarked
* drivers to panic the system. Once all drivers are taken care of,
* the whole INVARIANTS block should go away.
*/
if (!needs_epoch && !in_epoch(net_epoch_preempt)) {
static bool printedonce;
needs_epoch = true;
if (!printedonce) {
printedonce = true;
if_printf(ifp, "called %s w/o net epoch! "
"PLEASE file a bug report.", __func__);
#ifdef KDB
kdb_backtrace();
#endif
}
}
#endif
CURVNET_SET_QUIET(ifp->if_vnet);
if (__predict_false(needs_epoch))

2
sys/net/iflib.c
View File

@ -6010,7 +6010,7 @@ iflib_register(if_ctx_t ctx)
if_settransmitfn(ifp, iflib_if_transmit);
#endif
if_setqflushfn(ifp, iflib_if_qflush);
iflags = IFF_MULTICAST | IFF_KNOWSEPOCH;
iflags = IFF_MULTICAST;
if ((sctx->isc_flags & IFLIB_PSEUDO) &&
(sctx->isc_flags & IFLIB_PSEUDO_ETHER) == 0)

4
sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c
View File

@ -922,8 +922,8 @@ ipoib_intf_alloc(const char *name, struct ib_device *hca)
}
if_initname(dev, name, priv->unit);
if_setflags(dev, IFF_BROADCAST | IFF_MULTICAST);
if (hca->attrs.device_cap_flags & IB_DEVICE_KNOWSEPOCH)
if_setflagbits(dev, IFF_KNOWSEPOCH, 0);
if ((hca->attrs.device_cap_flags & IB_DEVICE_KNOWSEPOCH) == 0)
if_setflagbits(dev, IFF_NEEDSEPOCH, 0);
infiniband_ifattach(priv->dev, NULL, priv->broadcastaddr);