net/dpaa2: Avoid explicit cpumask var allocation on stack

For CONFIG_CPUMASK_OFFSTACK=y kernel, explicit allocation of cpumask
variable on stack is not recommended since it can cause potential stack
overflow.

Instead, kernel code should always use *cpumask_var API(s) to allocate
cpumask var in config-neutral way, leaving allocation strategy to
CONFIG_CPUMASK_OFFSTACK.

Use *cpumask_var API(s) to address it.

Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
Link: https://lore.kernel.org/r/20240331053441.1276826-3-dawei.li@shingroup.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
index 888509c..40e8818 100644 (file)
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -2896,11 +2896,14 @@ static int dpaa2_eth_xdp_xmit(struct net_device *net_dev, int n,
 static int update_xps(struct dpaa2_eth_priv *priv)
 {
        struct net_device *net_dev = priv->net_dev;
-       struct cpumask xps_mask;
-       struct dpaa2_eth_fq *fq;
        int i, num_queues, netdev_queues;
+       struct dpaa2_eth_fq *fq;
+       cpumask_var_t xps_mask;
        int err = 0;
 
+       if (!alloc_cpumask_var(&xps_mask, GFP_KERNEL))
+               return -ENOMEM;
+
        num_queues = dpaa2_eth_queue_count(priv);
        netdev_queues = (net_dev->num_tc ? : 1) * num_queues;
 
@@ -2910,16 +2913,17 @@ static int update_xps(struct dpaa2_eth_priv *priv)
        for (i = 0; i < netdev_queues; i++) {
                fq = &priv->fq[i % num_queues];
 
-               cpumask_clear(&xps_mask);
-               cpumask_set_cpu(fq->target_cpu, &xps_mask);
+               cpumask_clear(xps_mask);
+               cpumask_set_cpu(fq->target_cpu, xps_mask);
 
-               err = netif_set_xps_queue(net_dev, &xps_mask, i);
+               err = netif_set_xps_queue(net_dev, xps_mask, i);
                if (err) {
                        netdev_warn_once(net_dev, "Error setting XPS queue\n");
                        break;
                }
        }
 
+       free_cpumask_var(xps_mask);
        return err;
 }