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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/rump/net/lib/libvirtif
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These were originally made failable back in 2017 when if_initialize allocated a softint in every interface for link state changes, so that it could fail gracefully instead of panicking: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 And that softint in every interface has since been replaced by a single global workqueue, because link state changes require thread context but not low latency or high throughput: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/rump/net/lib/libvirtif')
-rw-r--r--sys/rump/net/lib/libvirtif/if_virt.c17
1 files changed, 5 insertions, 12 deletions
diff --git a/sys/rump/net/lib/libvirtif/if_virt.c b/sys/rump/net/lib/libvirtif/if_virt.c
index 5406ea956bd..46800769879 100644
--- a/sys/rump/net/lib/libvirtif/if_virt.c
+++ b/sys/rump/net/lib/libvirtif/if_virt.c
@@ -1,4 +1,4 @@
-/* $NetBSD: if_virt.c,v 1.58 2020/02/01 22:45:01 thorpej Exp $ */
+/* $NetBSD: if_virt.c,v 1.59 2021/06/16 00:21:20 riastradh Exp $ */
/*
* Copyright (c) 2008, 2013 Antti Kantee. All Rights Reserved.
@@ -26,7 +26,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_virt.c,v 1.58 2020/02/01 22:45:01 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_virt.c,v 1.59 2021/06/16 00:21:20 riastradh Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@@ -121,13 +121,7 @@ virtif_clone(struct if_clone *ifc, int num)
ifp->if_mtu = ETHERMTU;
ifp->if_dlt = DLT_EN10MB;
- error = if_initialize(ifp);
- if (error != 0) {
- aprint_error("%s: if_initialize failed(%d)\n", ifp->if_xname,
- error);
- goto fail_1;
- }
-
+ if_initialize(ifp);
if_register(ifp);
#ifndef RUMP_VIF_LINKSTR
@@ -140,17 +134,16 @@ virtif_clone(struct if_clone *ifc, int num)
sc->sc_linkstr = kmem_alloc(LINKSTRNUMLEN, KM_SLEEP);
if (sc->sc_linkstr == NULL) {
error = ENOMEM;
- goto fail_2;
+ goto fail;
}
snprintf(sc->sc_linkstr, LINKSTRNUMLEN, "%d", sc->sc_num);
error = virtif_create(ifp);
if (error) {
-fail_2:
+fail:
if_detach(ifp);
if (sc->sc_linkstr != NULL)
kmem_free(sc->sc_linkstr, LINKSTRNUMLEN);
#undef LINKSTRNUMLEN
-fail_1:
kmem_free(sc, sizeof(*sc));
ifp->if_softc = NULL;
}