genirq/affinity: Move actual irq vector spreading into a helper function

BugLink: http://bugs.launchpad.net/bugs/1759723
No functional change, just prepare for converting to 2-stage irq vector
spreading.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Link: https://lkml.kernel.org/r/20180308105358.1506-3-ming.lei@redhat.com
(cherry picked from commit b3e6aaa8d94d618e685c4df08bef991a4fb43923)
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.ibm.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 272c968d9ef139489262c3ee55ece41ddd66e81a..a9c36904500cd41f1ae3c834eeb9629895449d8a 100644 (file)
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -94,50 +94,19 @@ static int get_nodes_in_cpumask(cpumask_var_t *node_to_cpumask,
        return nodes;
 }
 
-/**
- * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
- * @nvecs:     The total number of vectors
- * @affd:      Description of the affinity requirements
- *
- * Returns the masks pointer or NULL if allocation failed.
- */
-struct cpumask *
-irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
+static int irq_build_affinity_masks(int nvecs, const struct irq_affinity *affd,
+                                   cpumask_var_t *node_to_cpumask,
+                                   const struct cpumask *cpu_mask,
+                                   struct cpumask *nmsk,
+                                   struct cpumask *masks)
 {
-       int n, nodes, cpus_per_vec, extra_vecs, curvec;
        int affv = nvecs - affd->pre_vectors - affd->post_vectors;
        int last_affv = affv + affd->pre_vectors;
+       int curvec = affd->pre_vectors;
        nodemask_t nodemsk = NODE_MASK_NONE;
-       struct cpumask *masks = NULL;
-       cpumask_var_t nmsk, *node_to_cpumask;
+       int n, nodes, cpus_per_vec, extra_vecs;
 
-       /*
-        * If there aren't any vectors left after applying the pre/post
-        * vectors don't bother with assigning affinity.
-        */
-       if (!affv)
-               return NULL;
-
-       if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
-               return NULL;
-
-       node_to_cpumask = alloc_node_to_cpumask();
-       if (!node_to_cpumask)
-               goto outcpumsk;
-
-       masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
-       if (!masks)
-               goto outnodemsk;
-
-       /* Fill out vectors at the beginning that don't need affinity */
-       for (curvec = 0; curvec < affd->pre_vectors; curvec++)
-               cpumask_copy(masks + curvec, irq_default_affinity);
-
-       /* Stabilize the cpumasks */
-       get_online_cpus();
-       build_node_to_cpumask(node_to_cpumask);
-       nodes = get_nodes_in_cpumask(node_to_cpumask, cpu_possible_mask,
-                                    &nodemsk);
+       nodes = get_nodes_in_cpumask(node_to_cpumask, cpu_mask, &nodemsk);
 
        /*
         * If the number of nodes in the mask is greater than or equal the
@@ -150,7 +119,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
                        if (++curvec == last_affv)
                                break;
                }
-               goto done;
+               goto out;
        }
 
        for_each_node_mask(n, nodemsk) {
@@ -160,7 +129,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
                vecs_per_node = (affv - (curvec - affd->pre_vectors)) / nodes;
 
                /* Get the cpus on this node which are in the mask */
-               cpumask_and(nmsk, cpu_possible_mask, node_to_cpumask[n]);
+               cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
 
                /* Calculate the number of cpus per vector */
                ncpus = cpumask_weight(nmsk);
@@ -186,7 +155,51 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
                --nodes;
        }
 
-done:
+out:
+       return curvec - affd->pre_vectors;
+}
+
+/**
+ * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
+ * @nvecs:     The total number of vectors
+ * @affd:      Description of the affinity requirements
+ *
+ * Returns the masks pointer or NULL if allocation failed.
+ */
+struct cpumask *
+irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
+{
+       cpumask_var_t nmsk, *node_to_cpumask;
+       struct cpumask *masks = NULL;
+       int curvec;
+
+       /*
+        * If there aren't any vectors left after applying the pre/post
+        * vectors don't bother with assigning affinity.
+        */
+       if (nvecs == affd->pre_vectors + affd->post_vectors)
+               return NULL;
+
+       if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
+               return NULL;
+
+       node_to_cpumask = alloc_node_to_cpumask();
+       if (!node_to_cpumask)
+               goto outcpumsk;
+
+       masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
+       if (!masks)
+               goto outnodemsk;
+
+       /* Fill out vectors at the beginning that don't need affinity */
+       for (curvec = 0; curvec < affd->pre_vectors; curvec++)
+               cpumask_copy(masks + curvec, irq_default_affinity);
+
+       /* Stabilize the cpumasks */
+       get_online_cpus();
+       build_node_to_cpumask(node_to_cpumask);
+       curvec += irq_build_affinity_masks(nvecs, affd, node_to_cpumask,
+                                          cpu_possible_mask, nmsk, masks);
        put_online_cpus();
 
        /* Fill out vectors at the end that don't need affinity */