genirq/affinity: Take reserved vectors into account when spreading irqs

The recent addition of reserved vectors at the beginning or the end of the
vector space did not take the reserved vectors at the beginning into
account for the various loop exit conditions. As a consequence the last
vectors of the spread area are not included into the spread algorithm and
are treated like the reserved vectors at the end of the vector space and
get the default affinity mask assigned.

Sum up the affinity vectors and the reserved vectors at the beginning and
use the sum as exit condition.

[ tglx: Fixed all conditions instead of only one and massaged changelog ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/1479201178-29604-2-git-send-email-hch@lst.deSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/affinity.c

@@ -61,6 +61,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
 {
 	int n, nodes, vecs_per_node, cpus_per_vec, extra_vecs, curvec;
 	int affv = nvecs - affd->pre_vectors - affd->post_vectors;
+	int last_affv = affv + affd->pre_vectors;
 	nodemask_t nodemsk = NODE_MASK_NONE;
 	struct cpumask *masks;
 	cpumask_var_t nmsk;
@@ -87,7 +88,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
 	if (affv <= nodes) {
 		for_each_node_mask(n, nodemsk) {
 			cpumask_copy(masks + curvec, cpumask_of_node(n));
-			if (++curvec == affv)
+			if (++curvec == last_affv)
 				break;
 		}
 		goto done;
@@ -107,7 +108,8 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
 		/* Calculate the number of cpus per vector */
 		ncpus = cpumask_weight(nmsk);
 
-		for (v = 0; curvec < affv && v < vecs_to_assign; curvec++, v++) {
+		for (v = 0; curvec < last_affv && v < vecs_to_assign;
+		     curvec++, v++) {
 			cpus_per_vec = ncpus / vecs_to_assign;
 
 			/* Account for extra vectors to compensate rounding errors */
@@ -119,7 +121,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
 			irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);
 		}
 
-		if (curvec >= affv)
+		if (curvec >= last_affv)
 			break;
 	}