build: eliminate WITH_MACVTAP flag entirely

This flag was originally created to indicate that either 1) the build
platform wasn't linux, 2) the build platform was linux, but the kernel
was too old to have macvtap support. Since there was already a switch
there, the ability to also disable it when 3) the kernel supports
macvtap but the user doesn't want it, was added in. I don't think that
(3) was ever an intentional goal, just something that grew naturally
out of having the flag there in the first place (unless possibly the
original author wanted a way to quickly disable their new code in case
it caused regressions elsewhere).

Now that the check for (2) has been removed, WITH_MACVTAP is just
checking (1) and (3), but (3) is pointless (because the extra code in
libvirt itself is miniscule, and the only external library needed for
it is libnl, which is also required for other unrelated features (and
itself has no subordinate dependencies and takes up < 1MB on
disk)). We can therfore eliminate the WITH_MACVTAP flag, as it is
functionally equivalent to WITH_LIBNL (which implies __linux__).

Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

libvirt.spec.in

@@ -1167,7 +1167,6 @@ export SOURCE_DATE_EPOCH=$(stat --printf='%Y' %{_specdir}/%{name}.spec)
            -Dyajl=enabled \
            %{?arg_sanlock} \
            -Dlibpcap=enabled \
-           -Dmacvtap=enabled \
            -Daudit=enabled \
            -Ddtrace=enabled \
            %{?arg_firewalld} \

meson.build

@@ -1159,16 +1159,6 @@ libxml_dep = dependency('libxml-2.0', version: '>=' + libxml_version)
 cc = meson.get_compiler('c')
 m_dep = cc.find_library('m', required : false)
 
-if host_machine.system() == 'linux'
-  if not get_option('macvtap').disabled()
-    conf.set('WITH_MACVTAP', 1)
-  endif
-else
-  if get_option('macvtap').enabled()
-    error('macvtap is not supported on this platform.')
-  endif
-endif
-
 netcf_version = '0.1.8'
 netcf_dep = dependency('netcf', version: '>=' + netcf_version, required: get_option('netcf'))
 if netcf_dep.found()

meson_options.txt

@@ -26,7 +26,6 @@ option('libiscsi', type: 'feature', value: 'auto', description: 'libiscsi suppor
 option('libpcap', type: 'feature', value: 'auto', description: 'libpcap support')
 option('libssh', type: 'feature', value: 'auto', description: 'libssh support')
 option('libssh2', type: 'feature', value: 'auto', description: 'libssh2 support')
-option('macvtap', type: 'feature', value: 'auto', description: 'enable macvtap device')
 option('netcf', type: 'feature', value: 'auto', description: 'netcf support')
 option('nls', type: 'feature', value: 'auto', description: 'nls support')
 option('numactl', type: 'feature', value: 'auto', description: 'numactl support')

src/util/virnetdevmacvlan.c

@@ -40,7 +40,7 @@ VIR_ENUM_IMPL(virNetDevMacVLanMode,
               "passthrough",
 );
 
-#if WITH_MACVTAP
+#if defined(WITH_LIBNL)
 # include <fcntl.h>
 
 # include <net/if.h>
@@ -1043,7 +1043,7 @@ int virNetDevMacVLanRestartWithVPortProfile(const char *cr_ifname,
 
 }
 
-#else /* ! WITH_MACVTAP */
+#else /* ! WITH_LIBNL */
 bool virNetDevMacVLanIsMacvtap(const char *ifname G_GNUC_UNUSED)
 {
     virReportSystemError(ENOSYS, "%s",
@@ -1149,4 +1149,4 @@ void virNetDevMacVLanReserveName(const char *name G_GNUC_UNUSED)
     virReportSystemError(ENOSYS, "%s",
                          _("Cannot create macvlan devices on this platform"));
 }
-#endif /* ! WITH_MACVTAP */
+#endif /* ! WITH_LIBNL */