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authorriastradh <riastradh@NetBSD.org>2021-06-16 00:21:17 +0000
committerriastradh <riastradh@NetBSD.org>2021-06-16 00:21:17 +0000
commitbbdda93be2f0bfefe91466b398fe42700a6ea284 (patch)
treee75e77046575209dbb21f73d0bc44c61ec0ec6c0 /sys/dev/hyperv
parent5a96957fa793651c8e7093a5a4c2fcae87232af2 (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These were originally made failable back in 2017 when if_initialize allocated a softint in every interface for link state changes, so that it could fail gracefully instead of panicking: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 And that softint in every interface has since been replaced by a single global workqueue, because link state changes require thread context but not low latency or high throughput: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')
-rw-r--r--sys/dev/hyperv/if_hvn.c11
1 files changed, 3 insertions, 8 deletions
diff --git a/sys/dev/hyperv/if_hvn.c b/sys/dev/hyperv/if_hvn.c
index aa1aa499738..41f8495c4e7 100644
--- a/sys/dev/hyperv/if_hvn.c
+++ b/sys/dev/hyperv/if_hvn.c
@@ -1,4 +1,4 @@
-/* $NetBSD: if_hvn.c,v 1.20 2021/01/29 04:38:49 nonaka Exp $ */
+/* $NetBSD: if_hvn.c,v 1.21 2021/06/16 00:21:18 riastradh Exp $ */
/* $OpenBSD: if_hvn.c,v 1.39 2018/03/11 14:31:34 mikeb Exp $ */
/*-
@@ -35,7 +35,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_hvn.c,v 1.20 2021/01/29 04:38:49 nonaka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_hvn.c,v 1.21 2021/06/16 00:21:18 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_inet.h"
@@ -243,7 +243,6 @@ hvn_attach(device_t parent, device_t self, void *aux)
struct vmbus_attach_args *aa = aux;
struct ifnet *ifp = SC2IFP(sc);
uint8_t enaddr[ETHER_ADDR_LEN];
- int error;
sc->sc_dev = self;
sc->sc_vmbus = (struct vmbus_softc *)device_private(parent);
@@ -302,11 +301,7 @@ hvn_attach(device_t parent, device_t self, void *aux)
ifmedia_add(&sc->sc_media, IFM_ETHER | IFM_MANUAL, 0, NULL);
ifmedia_set(&sc->sc_media, IFM_ETHER | IFM_MANUAL);
- error = if_initialize(ifp);
- if (error) {
- aprint_error_dev(self, "if_initialize failed(%d)\n", error);
- goto fail3;
- }
+ if_initialize(ifp);
sc->sc_ipq = if_percpuq_create(ifp);
if_deferred_start_init(ifp, NULL);