File libvirt-util-increase-libnl-buffer-size.patch of Package libvirt

From 82b2661f544b048dfcfdd65cee0b424b95e0db6e Mon Sep 17 00:00:00 2001
Message-Id: <82b2661f544b048dfcfdd65cee0b424b95e0db6e@dist-git>
From: Leno Hou <houqy@linux.vnet.ibm.com>
Date: Mon, 15 Feb 2016 06:59:35 -0500
Subject: [PATCH] util: increase libnl buffer size

Part of fix for: https://bugzilla.redhat.com/show_bug.cgi?id=1276478

In the following cases nl_recv() was returning the error "No buffer
space available":

* When switching CPUs to offline/online in a system more than 128 cpus
* When using virsh to destroy domain in a system with many interfaces

This patch sets the buffer size for all netlink sockets created by
libnl to 128K and turns on message peeking for nl_recv(). This
eliminates the "No buffer space available" errors seen in the cases
above, and also preempts other future errors the smaller buffers could
have caused.

Signed-off-by: Leno Hou <houqy@linux.vnet.ibm.com>
Signed-off-by: Laine Stump <laine@laine.org>

(cherry pick from commit 8c70d04bab7278c96390a913fa949a17cd3124f9 with
small conflict cause by upstream change of error: label to cleanup:
(also replaced incorrect "return -EINVAL" downstream with "return
-1").
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/util/virnetlink.c | 86 ++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 58 insertions(+), 28 deletions(-)

diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
index 8a8bfae..7013f0c 100644
--- a/src/util/virnetlink.c
+++ b/src/util/virnetlink.c
@@ -1,6 +1,6 @@
 /*
- * Copyright (C) 2010-2012 Red Hat, Inc.
- * Copyright (C) 2010-2012 IBM Corporation
+ * Copyright (C) 2010-2016 Red Hat, Inc.
+ * Copyright (C) 2010-2012, 2016 IBM Corporation
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -63,10 +63,12 @@ struct virNetlinkEventHandle {
 
 # ifdef HAVE_LIBNL1
 #  define virNetlinkAlloc nl_handle_alloc
+#  define virNetlinkSetBufferSize nl_set_buffer_size
 #  define virNetlinkFree nl_handle_destroy
 typedef struct nl_handle virNetlinkHandle;
 # else
 #  define virNetlinkAlloc nl_socket_alloc
+#  define virNetlinkSetBufferSize nl_socket_set_buffer_size
 #  define virNetlinkFree nl_socket_free
 typedef struct nl_sock virNetlinkHandle;
 # endif
@@ -158,6 +160,57 @@ virNetlinkShutdown(void)
     }
 }
 
+
+/**
+ * virNetLinkCreateSocket:
+ *
+ * @protocol: which protocol to connect to (e.g. NETLINK_ROUTE,
+ *
+ * Create a netlink socket, set its buffer size, and turn on message
+ * peeking (so the buffer size can be dynamically increased if
+ * needed).
+ *
+ * Returns a handle to the new netlink socket, or 0 if there was a failure.
+ *
+ */
+static virNetlinkHandle *
+virNetlinkCreateSocket(int protocol)
+{
+    virNetlinkHandle *nlhandle = NULL;
+
+    if (!(nlhandle = virNetlinkAlloc())) {
+        virReportSystemError(errno, "%s",
+                             _("cannot allocate nlhandle for netlink"));
+        goto error;
+    }
+    if (nl_connect(nlhandle, protocol) < 0) {
+        virReportSystemError(errno,
+                             _("cannot connect to netlink socket "
+                               "with protocol %d"), protocol);
+        goto error;
+    }
+
+    if (virNetlinkSetBufferSize(nlhandle, 131702, 0) < 0) {
+        virReportSystemError(errno, "%s",
+                             _("cannot set netlink socket buffer "
+                               "size to 128k"));
+        goto error;
+    }
+    nl_socket_enable_msg_peek(nlhandle);
+
+ cleanup:
+    return nlhandle;
+
+ error:
+    if (nlhandle) {
+        nl_close(nlhandle);
+        virNetlinkFree(nlhandle);
+        nlhandle = NULL;
+    }
+    goto cleanup;
+}
+
+
 /**
  * virNetlinkCommand:
  * @nlmsg: pointer to netlink message
@@ -197,23 +250,11 @@ int virNetlinkCommand(struct nl_msg *nl_msg,
     if (protocol >= MAX_LINKS) {
         virReportSystemError(EINVAL,
                              _("invalid protocol argument: %d"), protocol);
-        return -EINVAL;
-    }
-
-    nlhandle = virNetlinkAlloc();
-    if (!nlhandle) {
-        virReportSystemError(errno,
-                             "%s", _("cannot allocate nlhandle for netlink"));
         return -1;
     }
 
-    if (nl_connect(nlhandle, protocol) < 0) {
-        virReportSystemError(errno,
-                        _("cannot connect to netlink socket with protocol %d"),
-                             protocol);
-        rc = -1;
-        goto error;
-    }
+    if (!(nlhandle = virNetlinkCreateSocket(protocol)))
+        return -1;
 
     fd = nl_socket_get_fd(nlhandle);
     if (fd < 0) {
@@ -529,19 +570,8 @@ virNetlinkEventServiceStart(unsigned int protocol, unsigned int groups)
     virNetlinkEventServerLock(srv);
 
     /* Allocate a new socket and get fd */
-    srv->netlinknh = virNetlinkAlloc();
-
-    if (!srv->netlinknh) {
-        virReportSystemError(errno,
-                             "%s", _("cannot allocate nlhandle for virNetlinkEvent server"));
+    if (!(srv->netlinknh = virNetlinkCreateSocket(protocol)))
         goto error_locked;
-    }
-
-    if (nl_connect(srv->netlinknh, protocol) < 0) {
-        virReportSystemError(errno,
-                             _("cannot connect to netlink socket with protocol %d"), protocol);
-        goto error_server;
-    }
 
     fd = nl_socket_get_fd(srv->netlinknh);
     if (fd < 0) {
-- 
2.7.1