sd-device-monitor: fix ordering of setting buffer size

By b1c097af8df58a94cba031a347061b7cb9b62d9b (#10239), the receive buffer
size for uevents was set by SO_RCVBUF at first, and fallback to
use SO_RCVBUFFORCE. So, as SO_RCVBUF limits to the buffer size
net.core.rmem_max, which is usually much smaller than 128MB udevd requests,
uevents buffer size was not sufficient.

This fixes the ordering of the request: SO_RCVBUFFORCE first, and
fallback to SO_RCVBUF. Then, udevd's uevent buffer size can be set to
128MB.

This also revert 903893237a2105b05671fe87b8f5d5e7417040d2.

Fixes #11314 and #10754.

1 files changed, 2 insertions, 8 deletions

diff --git a/src/libsystemd/sd-device/device-monitor.c b/src/libsystemd/sd-device/device-monitor.c
index b86932663e..a6230d382a 100644
--- a/src/libsystemd/sd-device/device-monitor.c
+++ b/src/libsystemd/sd-device/device-monitor.c
@@ -93,14 +93,8 @@ _public_ int sd_device_monitor_set_receive_buffer_size(sd_device_monitor *m, siz
         assert_return(m, -EINVAL);
         assert_return((size_t) n == size, -EINVAL);
 
-        if (m->bound)
-                return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
-                                       "sd-device-monitor: Socket fd is already bound. "
-                                       "It may be dangerous to change buffer size. "
-                                       "Refusing to change buffer size.");
-
-        if (setsockopt_int(m->sock, SOL_SOCKET, SO_RCVBUF, n) < 0) {
-                r = setsockopt_int(m->sock, SOL_SOCKET, SO_RCVBUFFORCE, n);
+        if (setsockopt_int(m->sock, SOL_SOCKET, SO_RCVBUFFORCE, n) < 0) {
+                r = setsockopt_int(m->sock, SOL_SOCKET, SO_RCVBUF, n);
                 if (r < 0)
                         return r;
         }