RDMA: hfi1: fix possible divide-by-zero in find_hw_thread_mask()

The function divides number of online CPUs by num_core_siblings, and
later checks the divider by zero. This implies a possibility to get
and divide-by-zero runtime error. Fix it by moving the check prior to
division. This also helps to save one indentation level.

Signed-off-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Link: https://patch.msgid.link/20250604193947.11834-3-yury.norov@gmail.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

diff --git a/drivers/infiniband/hw/hfi1/affinity.c b/drivers/infiniband/hw/hfi1/affinity.c
index 7ead8746b79b38314aaebbd50071c065df7d5166..f2c530ab85a5630d3f618507eee64ae8e4492191 100644 (file)
--- a/drivers/infiniband/hw/hfi1/affinity.c
+++ b/drivers/infiniband/hw/hfi1/affinity.c
@@ -964,31 +964,35 @@ static void find_hw_thread_mask(uint hw_thread_no, cpumask_var_t hw_thread_mask,
                                struct hfi1_affinity_node_list *affinity)
 {
        int possible, curr_cpu, i;
-       uint num_cores_per_socket = node_affinity.num_online_cpus /
+       uint num_cores_per_socket;
+
+       cpumask_copy(hw_thread_mask, &affinity->proc.mask);
+
+       if (affinity->num_core_siblings == 0)
+               return;
+
+       num_cores_per_socket = node_affinity.num_online_cpus /
                                        affinity->num_core_siblings /
                                                node_affinity.num_online_nodes;
 
-       cpumask_copy(hw_thread_mask, &affinity->proc.mask);
-       if (affinity->num_core_siblings > 0) {
-               /* Removing other siblings not needed for now */
-               possible = cpumask_weight(hw_thread_mask);
-               curr_cpu = cpumask_first(hw_thread_mask);
-               for (i = 0;
-                    i < num_cores_per_socket * node_affinity.num_online_nodes;
-                    i++)
-                       curr_cpu = cpumask_next(curr_cpu, hw_thread_mask);
-
-               for (; i < possible; i++) {
-                       cpumask_clear_cpu(curr_cpu, hw_thread_mask);
-                       curr_cpu = cpumask_next(curr_cpu, hw_thread_mask);
-               }
+       /* Removing other siblings not needed for now */
+       possible = cpumask_weight(hw_thread_mask);
+       curr_cpu = cpumask_first(hw_thread_mask);
+       for (i = 0;
+            i < num_cores_per_socket * node_affinity.num_online_nodes;
+            i++)
+               curr_cpu = cpumask_next(curr_cpu, hw_thread_mask);
 
-               /* Identifying correct HW threads within physical cores */
-               cpumask_shift_left(hw_thread_mask, hw_thread_mask,
-                                  num_cores_per_socket *
-                                  node_affinity.num_online_nodes *
-                                  hw_thread_no);
+       for (; i < possible; i++) {
+               cpumask_clear_cpu(curr_cpu, hw_thread_mask);
+               curr_cpu = cpumask_next(curr_cpu, hw_thread_mask);
        }
+
+       /* Identifying correct HW threads within physical cores */
+       cpumask_shift_left(hw_thread_mask, hw_thread_mask,
+                          num_cores_per_socket *
+                          node_affinity.num_online_nodes *
+                          hw_thread_no);
 }
 
 int hfi1_get_proc_affinity(int node)