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/dev/usb/if_umb.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These were originally made failable back in 2017 when if_initialize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has since been replaced by a single global workqueue, because link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/dev/usb/if_umb.c')
| -rw-r--r-- | sys/dev/usb/if_umb.c | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/sys/dev/usb/if_umb.c b/sys/dev/usb/if_umb.c index 30b0f585d05..1aead36ba7e 100644 --- a/sys/dev/usb/if_umb.c +++ b/sys/dev/usb/if_umb.c @@ -1,4 +1,4 @@ -/* $NetBSD: if_umb.c,v 1.19 2020/03/24 07:12:16 maxv Exp $ */ +/* $NetBSD: if_umb.c,v 1.20 2021/06/16 00:21:19 riastradh Exp $ */ /* $OpenBSD: if_umb.c,v 1.20 2018/09/10 17:00:45 gerhard Exp $ */ /* @@ -26,7 +26,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: if_umb.c,v 1.19 2020/03/24 07:12:16 maxv Exp $"); +__KERNEL_RCSID(0, "$NetBSD: if_umb.c,v 1.20 2021/06/16 00:21:19 riastradh Exp $"); #ifdef _KERNEL_OPT #include "opt_inet.h" @@ -311,7 +311,6 @@ umb_attach(device_t parent, device_t self, void *aux) int altnum; int s; struct ifnet *ifp; - int rv; sc->sc_dev = self; sc->sc_udev = uiaa->uiaa_device; @@ -532,12 +531,7 @@ umb_attach(device_t parent, device_t self, void *aux) IFQ_SET_READY(&ifp->if_snd); /* attach the interface */ - rv = if_initialize(ifp); - if (rv != 0) { - aprint_error_dev(self, "if_initialize failed(%d)\n", rv); - splx(s); - return; - } + if_initialize(ifp); if_register(ifp); if_alloc_sadl(ifp); |
