diff options
| author | riastradh <riastradh@NetBSD.org> | 2021-06-16 00:21:17 +0000 |
|---|---|---|
| committer | riastradh <riastradh@NetBSD.org> | 2021-06-16 00:21:17 +0000 |
| commit | bbdda93be2f0bfefe91466b398fe42700a6ea284 (patch) | |
| tree | e75e77046575209dbb21f73d0bc44c61ec0ec6c0 /sys/net/if_l2tp.c | |
| parent | 5a96957fa793651c8e7093a5a4c2fcae87232af2 (diff) | |
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These were originally made failable back in 2017 when if_initialize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has since been replaced by a single global workqueue, because link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.
Diffstat (limited to 'sys/net/if_l2tp.c')
| -rw-r--r-- | sys/net/if_l2tp.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/sys/net/if_l2tp.c b/sys/net/if_l2tp.c index aa3c10be429..af2ce9baec4 100644 --- a/sys/net/if_l2tp.c +++ b/sys/net/if_l2tp.c @@ -1,4 +1,4 @@ -/* $NetBSD: if_l2tp.c,v 1.46 2020/10/25 08:18:39 roy Exp $ */ +/* $NetBSD: if_l2tp.c,v 1.47 2021/06/16 00:21:19 riastradh Exp $ */ /* * Copyright (c) 2017 Internet Initiative Japan Inc. @@ -31,7 +31,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: if_l2tp.c,v 1.46 2020/10/25 08:18:39 roy Exp $"); +__KERNEL_RCSID(0, "$NetBSD: if_l2tp.c,v 1.47 2021/06/16 00:21:19 riastradh Exp $"); #ifdef _KERNEL_OPT #include "opt_inet.h" @@ -281,7 +281,6 @@ l2tp_clone_create(struct if_clone *ifc, int unit) int l2tpattach0(struct l2tp_softc *sc) { - int rv; sc->l2tp_ec.ec_if.if_addrlen = 0; sc->l2tp_ec.ec_if.if_mtu = L2TP_MTU; @@ -321,9 +320,7 @@ l2tpattach0(struct l2tp_softc *sc) * if_percpuq_enqueue(). However, that causes recursive softnet_lock * when NET_MPSAFE is not set. */ - rv = if_attach(&sc->l2tp_ec.ec_if); - if (rv != 0) - return rv; + if_attach(&sc->l2tp_ec.ec_if); if_link_state_change(&sc->l2tp_ec.ec_if, LINK_STATE_DOWN); if_alloc_sadl(&sc->l2tp_ec.ec_if); bpf_attach(&sc->l2tp_ec.ec_if, DLT_EN10MB, sizeof(struct ether_header)); |
