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Wed, 16 Jun 2021 00:21:17 +0000 Subject: if_attach and if_initialize cannot fail, don't test return value These were originally made failable back in 2017 when if_initialize allocated a softint in every interface for link state changes, so that it could fail gracefully instead of panicking: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 And that softint in every interface has since been replaced by a single global workqueue, because link state changes require thread context but not low latency or high throughput: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/dev/hyperv/if_hvn.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) (limited to 'sys/dev/hyperv') diff --git a/sys/dev/hyperv/if_hvn.c b/sys/dev/hyperv/if_hvn.c index aa1aa499738..41f8495c4e7 100644 --- a/sys/dev/hyperv/if_hvn.c +++ b/sys/dev/hyperv/if_hvn.c @@ -1,4 +1,4 @@ -/* $NetBSD: if_hvn.c,v 1.20 2021/01/29 04:38:49 nonaka Exp $ */ +/* $NetBSD: if_hvn.c,v 1.21 2021/06/16 00:21:18 riastradh Exp $ */ /* $OpenBSD: if_hvn.c,v 1.39 2018/03/11 14:31:34 mikeb Exp $ */ /*- @@ -35,7 +35,7 @@ */ #include -__KERNEL_RCSID(0, "$NetBSD: if_hvn.c,v 1.20 2021/01/29 04:38:49 nonaka Exp $"); +__KERNEL_RCSID(0, "$NetBSD: if_hvn.c,v 1.21 2021/06/16 00:21:18 riastradh Exp $"); #ifdef _KERNEL_OPT #include "opt_inet.h" @@ -243,7 +243,6 @@ hvn_attach(device_t parent, device_t self, void *aux) struct vmbus_attach_args *aa = aux; struct ifnet *ifp = SC2IFP(sc); uint8_t enaddr[ETHER_ADDR_LEN]; - int error; sc->sc_dev = self; sc->sc_vmbus = (struct vmbus_softc *)device_private(parent); @@ -302,11 +301,7 @@ hvn_attach(device_t parent, device_t self, void *aux) ifmedia_add(&sc->sc_media, IFM_ETHER | IFM_MANUAL, 0, NULL); ifmedia_set(&sc->sc_media, IFM_ETHER | IFM_MANUAL); - error = if_initialize(ifp); - if (error) { - aprint_error_dev(self, "if_initialize failed(%d)\n", error); - goto fail3; - } + if_initialize(ifp); sc->sc_ipq = if_percpuq_create(ifp); if_deferred_start_init(ifp, NULL); -- cgit