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/hyperv/files.hyperv | |
| 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These were originally made failable back in 2017 when if_initialize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has since been replaced by a single global workqueue, because link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/hyperv/files.hyperv')
0 files changed, 0 insertions, 0 deletions
