xen-netback: respect user provided max_queues

Originally that parameter was always reset to num_online_cpus during
module initialisation, which renders it useless.

The fix is to only set max_queues to num_online_cpus when user has not
provided a value.

Reported-by: Johnny Strom <johnny.strom@linuxsolutions.fi>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index b588b1a08cd4..abc1381264fc 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -2114,8 +2114,11 @@ static int __init netback_init(void)
         if (!xen_domain())
                 return -ENODEV;
 
-        /* Allow as many queues as there are CPUs, by default */
-        xenvif_max_queues = num_online_cpus();
+        /* Allow as many queues as there are CPUs if user has not
+         * specified a value.
+         */
+        if (xenvif_max_queues == 0)
+                xenvif_max_queues = num_online_cpus();
 
         if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
                 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",