genirq/affinity: Handle pre/post vectors in irq_create_affinity_masks()

Only calculate the affinity for the main I/O vectors, and skip the
pre or post vectors specified by struct irq_affinity.

Also remove the irq_affinity cpumask argument that has never been used.
If we ever need it in the future we can pass it through struct
irq_affinity.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Link: http://lkml.kernel.org/r/1478654107-7384-4-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 31 insertions, 25 deletions

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index dad2da7cf80e..f4a108b59336 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -553,12 +553,13 @@ error_attrs:
 static struct msi_desc *
 msi_setup_entry(struct pci_dev *dev, int nvec, bool affinity)
 {
+        static const struct irq_affinity default_affd;
         struct cpumask *masks = NULL;
         struct msi_desc *entry;
         u16 control;
 
         if (affinity) {
-                masks = irq_create_affinity_masks(dev->irq_affinity, nvec);
+                masks = irq_create_affinity_masks(nvec, &default_affd);
                 if (!masks)
                         pr_err("Unable to allocate affinity masks, ignoring\n");
         }
@@ -692,12 +693,13 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
                               struct msix_entry *entries, int nvec,
                               bool affinity)
 {
+        static const struct irq_affinity default_affd;
         struct cpumask *curmsk, *masks = NULL;
         struct msi_desc *entry;
         int ret, i;
 
         if (affinity) {
-                masks = irq_create_affinity_masks(dev->irq_affinity, nvec);
+                masks = irq_create_affinity_masks(nvec, &default_affd);
                 if (!masks)
                         pr_err("Unable to allocate affinity masks, ignoring\n");
         }
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 9081f23bc0ff..53144e78a369 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -290,7 +290,7 @@ extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
 extern int
 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
 
-struct cpumask *irq_create_affinity_masks(const struct cpumask *affinity, int nvec);
+struct cpumask *irq_create_affinity_masks(int nvec, const struct irq_affinity *affd);
 int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd);
 
 #else /* CONFIG_SMP */
@@ -325,7 +325,7 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 }
 
 static inline struct cpumask *
-irq_create_affinity_masks(const struct cpumask *affinity, int nvec)
+irq_create_affinity_masks(int nvec, const struct irq_affinity *affd)
 {
         return NULL;
 }
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 8d9259727cb4..17360bd9619b 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -51,16 +51,16 @@ static int get_nodes_in_cpumask(const struct cpumask *mask, nodemask_t *nodemsk)
 
 /**
  * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
- * @affinity:           The affinity mask to spread. If NULL cpu_online_mask
- *                      is used
- * @nvecs:              The number of vectors
+ * @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(const struct cpumask *affinity,
-                                          int nvec)
+struct cpumask *
+irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
 {
-        int n, nodes, vecs_per_node, cpus_per_vec, extra_vecs, curvec = 0;
+        int n, nodes, vecs_per_node, cpus_per_vec, extra_vecs, curvec;
+        int affv = nvecs - affd->pre_vectors - affd->post_vectors;
         nodemask_t nodemsk = NODE_MASK_NONE;
         struct cpumask *masks;
         cpumask_var_t nmsk;
@@ -68,46 +68,46 @@ struct cpumask *irq_create_affinity_masks(const struct cpumask *affinity,
         if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
                 return NULL;
 
-        masks = kzalloc(nvec * sizeof(*masks), GFP_KERNEL);
+        masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
         if (!masks)
                 goto out;
 
+        /* Fill out vectors at the beginning that don't need affinity */
+        for (curvec = 0; curvec < affd->pre_vectors; curvec++)
+                cpumask_copy(masks + curvec, cpu_possible_mask);
+
         /* Stabilize the cpumasks */
         get_online_cpus();
-        /* If the supplied affinity mask is NULL, use cpu online mask */
-        if (!affinity)
-                affinity = cpu_online_mask;
-
-        nodes = get_nodes_in_cpumask(affinity, &nodemsk);
+        nodes = get_nodes_in_cpumask(cpu_online_mask, &nodemsk);
 
         /*
          * If the number of nodes in the mask is less than or equal the
          * number of vectors we just spread the vectors across the nodes.
          */
-        if (nvec <= nodes) {
+        if (affv <= nodes) {
                 for_each_node_mask(n, nodemsk) {
                         cpumask_copy(masks + curvec, cpumask_of_node(n));
-                        if (++curvec == nvec)
+                        if (++curvec == affv)
                                 break;
                 }
-                goto outonl;
+                goto done;
         }
 
         /* Spread the vectors per node */
-        vecs_per_node = nvec / nodes;
+        vecs_per_node = affv / nodes;
         /* Account for rounding errors */
-        extra_vecs = nvec - (nodes * vecs_per_node);
+        extra_vecs = affv - (nodes * vecs_per_node);
 
         for_each_node_mask(n, nodemsk) {
                 int ncpus, v, vecs_to_assign = vecs_per_node;
 
                 /* Get the cpus on this node which are in the mask */
-                cpumask_and(nmsk, affinity, cpumask_of_node(n));
+                cpumask_and(nmsk, cpu_online_mask, cpumask_of_node(n));
 
                 /* Calculate the number of cpus per vector */
                 ncpus = cpumask_weight(nmsk);
 
-                for (v = 0; curvec < nvec && v < vecs_to_assign; curvec++, v++) {
+                for (v = 0; curvec < affv && v < vecs_to_assign; curvec++, v++) {
                         cpus_per_vec = ncpus / vecs_to_assign;
 
                         /* Account for extra vectors to compensate rounding errors */
@@ -119,12 +119,16 @@ struct cpumask *irq_create_affinity_masks(const struct cpumask *affinity,
                         irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);
                 }
 
-                if (curvec >= nvec)
+                if (curvec >= affv)
                         break;
         }
 
-outonl:
+done:
         put_online_cpus();
+
+        /* Fill out vectors at the end that don't need affinity */
+        for (; curvec < nvecs; curvec++)
+                cpumask_copy(masks + curvec, cpu_possible_mask);
 out:
         free_cpumask_var(nmsk);
         return masks;