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Wed, 16 Jun 2021 00:21:17 +0000 Subject: if_attach and if_initialize cannot fail, don't test return value These were originally made failable back in 2017 when if_initialize allocated a softint in every interface for link state changes, so that it could fail gracefully instead of panicking: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 And that softint in every interface has since been replaced by a single global workqueue, because link state changes require thread context but not low latency or high throughput: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/athn.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) (limited to 'sys/dev/ic/athn.c') diff --git a/sys/dev/ic/athn.c b/sys/dev/ic/athn.c index b6163dcf5a4..0a5779938c7 100644 --- a/sys/dev/ic/athn.c +++ b/sys/dev/ic/athn.c @@ -1,4 +1,4 @@ -/* $NetBSD: athn.c,v 1.24 2020/11/15 12:33:53 mlelstv Exp $ */ +/* $NetBSD: athn.c,v 1.25 2021/06/16 00:21:18 riastradh Exp $ */ /* $OpenBSD: athn.c,v 1.83 2014/07/22 13:12:11 mpi Exp $ */ /*- @@ -23,7 +23,7 @@ */ #include -__KERNEL_RCSID(0, "$NetBSD: athn.c,v 1.24 2020/11/15 12:33:53 mlelstv Exp $"); +__KERNEL_RCSID(0, "$NetBSD: athn.c,v 1.25 2021/06/16 00:21:18 riastradh Exp $"); #ifndef _MODULE #include "athn_usb.h" /* for NATHN_USB */ @@ -348,16 +348,7 @@ athn_attach(struct athn_softc *sc) IFQ_SET_READY(&ifp->if_snd); memcpy(ifp->if_xname, device_xname(sc->sc_dev), IFNAMSIZ); - error = if_initialize(ifp); - if (error != 0) { - aprint_error_dev(sc->sc_dev, "if_initialize failed(%d)\n", - error); - pmf_event_deregister(sc->sc_dev, PMFE_RADIO_OFF, - athn_pmf_wlan_off, false); - callout_destroy(&sc->sc_scan_to); - callout_destroy(&sc->sc_calib_to); - return error; - } + if_initialize(ifp); ieee80211_ifattach(ic); /* Use common softint-based if_input */ ifp->if_percpuq = if_percpuq_create(ifp); -- cgit