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

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: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Link: http://lkml.kernel.org/r/1478654107-7384-3-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/pci/msi.c

@@ -1061,6 +1061,7 @@ EXPORT_SYMBOL(pci_msi_enabled);
 static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
 		unsigned int flags)
 {
+	static const struct irq_affinity default_affd;
 	bool affinity = flags & PCI_IRQ_AFFINITY;
 	int nvec;
 	int rc;
@@ -1091,8 +1092,7 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
 
 	for (;;) {
 		if (affinity) {
-			nvec = irq_calc_affinity_vectors(dev->irq_affinity,
-					nvec);
+			nvec = irq_calc_affinity_vectors(nvec, &default_affd);
 			if (nvec < minvec)
 				return -ENOSPC;
 		}
@@ -1132,6 +1132,7 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
 		struct msix_entry *entries, int minvec, int maxvec,
 		unsigned int flags)
 {
+	static const struct irq_affinity default_affd;
 	bool affinity = flags & PCI_IRQ_AFFINITY;
 	int rc, nvec = maxvec;
 
@@ -1140,8 +1141,7 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
 
 	for (;;) {
 		if (affinity) {
-			nvec = irq_calc_affinity_vectors(dev->irq_affinity,
-					nvec);
+			nvec = irq_calc_affinity_vectors(nvec, &default_affd);
 			if (nvec < minvec)
 				return -ENOSPC;
 		}

include/linux/interrupt.h

@@ -291,7 +291,7 @@ 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);
-int irq_calc_affinity_vectors(const struct cpumask *affinity, int maxvec);
+int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd);
 
 #else /* CONFIG_SMP */
 
@@ -331,7 +331,7 @@ irq_create_affinity_masks(const struct cpumask *affinity, int nvec)
 }
 
 static inline int
-irq_calc_affinity_vectors(const struct cpumask *affinity, int maxvec)
+irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd)
 {
 	return maxvec;
 }

kernel/irq/affinity.c

@@ -131,24 +131,20 @@ out:
 }
 
 /**
- * irq_calc_affinity_vectors - Calculate to optimal number of vectors for a given affinity mask
- * @affinity:		The affinity mask to spread. If NULL cpu_online_mask
- *			is used
- * @maxvec:		The maximum number of vectors available
+ * irq_calc_affinity_vectors - Calculate the optimal number of vectors
+ * @maxvec:	The maximum number of vectors available
+ * @affd:	Description of the affinity requirements
  */
-int irq_calc_affinity_vectors(const struct cpumask *affinity, int maxvec)
+int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd)
 {
-	int cpus, ret;
+	int resv = affd->pre_vectors + affd->post_vectors;
+	int vecs = maxvec - resv;
+	int cpus;
 
 	/* Stabilize the cpumasks */
 	get_online_cpus();
-	/* If the supplied affinity mask is NULL, use cpu online mask */
-	if (!affinity)
-		affinity = cpu_online_mask;
-
-	cpus = cpumask_weight(affinity);
-	ret = (cpus < maxvec) ? cpus : maxvec;
-
+	cpus = cpumask_weight(cpu_online_mask);
 	put_online_cpus();
-	return ret;
+
+	return min(cpus, vecs) + resv;
 }