net: accept an empty mask in /sys/class/net/*/queues/rx-*/rps_cpus

We must accept an empty mask in store_rps_map(), or we are not able
to disable RPS on a queue.

Fixes: 07bbecb34106 ("net: Restrict receive packets queuing to housekeeping CPUs")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Maciej Żenczykowski <maze@google.com>
Cc: Alex Belits <abelits@marvell.com>
Cc: Nitesh Narayan Lal <nitesh@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 9de33b5..efec66f 100644 (file)
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -757,11 +757,13 @@ static ssize_t store_rps_map(struct netdev_rx_queue *queue,
                return err;
        }
 
-       hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;
-       cpumask_and(mask, mask, housekeeping_cpumask(hk_flags));
-       if (cpumask_empty(mask)) {
-               free_cpumask_var(mask);
-               return -EINVAL;
+       if (!cpumask_empty(mask)) {
+               hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;
+               cpumask_and(mask, mask, housekeeping_cpumask(hk_flags));
+               if (cpumask_empty(mask)) {
+                       free_cpumask_var(mask);
+                       return -EINVAL;
+               }
        }
 
        map = kzalloc(max_t(unsigned int,