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Wed, 16 Jun 2021 00:21:17 +0000 Subject: if_attach and if_initialize cannot fail, don't test return value These were originally made failable back in 2017 when if_initialize allocated a softint in every interface for link state changes, so that it could fail gracefully instead of panicking: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 And that softint in every interface has since been replaced by a single global workqueue, because link state changes require thread context but not low latency or high throughput: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/ic/wi.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) (limited to 'sys/dev/ic/wi.c') diff --git a/sys/dev/ic/wi.c b/sys/dev/ic/wi.c index 787fcc481a9..602ce27ce55 100644 --- a/sys/dev/ic/wi.c +++ b/sys/dev/ic/wi.c @@ -1,4 +1,4 @@ -/* $NetBSD: wi.c,v 1.255 2020/01/30 04:56:11 thorpej Exp $ */ +/* $NetBSD: wi.c,v 1.256 2021/06/16 00:21:18 riastradh Exp $ */ /*- * Copyright (c) 2004 The NetBSD Foundation, Inc. @@ -99,7 +99,7 @@ */ #include -__KERNEL_RCSID(0, "$NetBSD: wi.c,v 1.255 2020/01/30 04:56:11 thorpej Exp $"); +__KERNEL_RCSID(0, "$NetBSD: wi.c,v 1.256 2021/06/16 00:21:18 riastradh Exp $"); #define WI_HERMES_AUTOINC_WAR /* Work around data write autoinc bug. */ #define WI_HERMES_STATS_WAR /* Work around stats counter bug. */ @@ -370,7 +370,7 @@ wi_attach(struct wi_softc *sc, const uint8_t *macaddr) static const uint8_t empty_macaddr[IEEE80211_ADDR_LEN] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; - int s, rv; + int s; sc->sc_soft_ih = softint_establish(SOFTINT_NET, wi_softintr, sc); if (sc->sc_soft_ih == NULL) { @@ -546,11 +546,7 @@ wi_attach(struct wi_softc *sc, const uint8_t *macaddr) /* * Call MI attach routines. */ - rv = if_initialize(ifp); - if (rv != 0) { - aprint_error_dev(sc->sc_dev, "if_initialize failed(%d)\n", rv); - goto fail_2; - } + if_initialize(ifp); ieee80211_ifattach(ic); /* Use common softint-based if_input */ ifp->if_percpuq = if_percpuq_create(ifp); @@ -588,9 +584,6 @@ wi_attach(struct wi_softc *sc, const uint8_t *macaddr) ieee80211_announce(ic); return 0; -fail_2: - callout_destroy(&sc->sc_rssadapt_ch); - fail: splx(s); softint_disestablish(sc->sc_soft_ih); sc->sc_soft_ih = NULL; -- cgit