From bbdda93be2f0bfefe91466b398fe42700a6ea284 Mon Sep 17 00:00:00 2001 From: riastradh Date: Wed, 16 Jun 2021 00:21:17 +0000 Subject: if_attach and if_initialize cannot fail, don't test return value These were originally made failable back in 2017 when if_initialize allocated a softint in every interface for link state changes, so that it could fail gracefully instead of panicking: https://mail-index.NetBSD.org/source-changes/2017/10/23/msg089053.html However, this spawned many seldom- or never-tested error branches, which are risky to have around. And that softint in every interface has since been replaced by a single global workqueue, because link state changes require thread context but not low latency or high throughput: https://mail-index.NetBSD.org/source-changes/2020/02/06/msg113759.html So there is no longer any reason for if_initialize to fail. (The subroutine if_stats_init can't fail because percpu_alloc can't fail either.) There is a snag: the softint_establish in if_percpuq_create could fail, potentially leading to bad consequences later on trying to use the softint. This change doesn't introduce any new bugs because of the snag -- if_percpuq_attach was already broken. However, the snag can be better addressed without spawning error branches, either by using a single softint or making softints less scarce. (Separate commit will change the signatures of if_attach and if_initialize to return void, scheduled to ride whatever is the next convenient kernel bump.) Patch and testing on amd64 and evbmips64-eb by maya@; commit message soliloquy, and compile-testing on evbppc/i386/earmv7hf, by me. --- sys/arch/usermode/dev/if_veth.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) (limited to 'sys/arch/usermode/dev') diff --git a/sys/arch/usermode/dev/if_veth.c b/sys/arch/usermode/dev/if_veth.c index a0ccd024bbb..a9488bf9c75 100644 --- a/sys/arch/usermode/dev/if_veth.c +++ b/sys/arch/usermode/dev/if_veth.c @@ -1,4 +1,4 @@ -/* $NetBSD: if_veth.c,v 1.14 2020/02/05 07:18:16 skrll Exp $ */ +/* $NetBSD: if_veth.c,v 1.15 2021/06/16 00:21:18 riastradh Exp $ */ /*- * Copyright (c) 2011 Jared D. McNeill @@ -27,7 +27,7 @@ */ #include -__KERNEL_RCSID(0, "$NetBSD: if_veth.c,v 1.14 2020/02/05 07:18:16 skrll Exp $"); +__KERNEL_RCSID(0, "$NetBSD: if_veth.c,v 1.15 2021/06/16 00:21:18 riastradh Exp $"); #include #include @@ -102,7 +102,6 @@ veth_attach(device_t parent, device_t self, void *opaque) struct veth_softc *sc = device_private(self); struct thunkbus_attach_args *taa = opaque; struct ifnet *ifp = &sc->sc_ec.ec_if; - int rv; sc->sc_dev = self; @@ -138,13 +137,7 @@ veth_attach(device_t parent, device_t self, void *opaque) IFQ_SET_MAXLEN(&ifp->if_snd, IFQ_MAXLEN); IFQ_SET_READY(&ifq->if_snd); - rv = if_initialize(ifp); - if (rv != 0) { - aprint_error_dev(self, "if_initialize failed(%d)\n", rv); - thunk_close(sc->sc_tapfd); - pmf_device_deregister(self); - return; /* Error */ - } + if_initialize(ifp); ether_ifattach(ifp, sc->sc_eaddr); if_register(ifp); -- cgit