[tip:irq/urgent] genirq/affinity: Fix calculating vectors to assign

[tip-bot for Keith Busch]

Commit-ID:  b72f8051f34b8164a62391e3676edc34523c5952
Gitweb:     http://git.kernel.org/tip/b72f8051f34b8164a62391e3676edc34523c5952
Author:     Keith Busch <keith.busch@xxxxxxxxx>
AuthorDate: Wed, 19 Apr 2017 19:51:10 -0400
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 20 Apr 2017 16:03:09 +0200

genirq/affinity: Fix calculating vectors to assign

The vectors_per_node is calculated from the remaining available vectors.
The current vector starts after pre_vectors, so we need to subtract that
from the current to properly account for the number of remaining vectors
to assign.

Fixes: 3412386b531 ("irq/affinity: Fix extra vecs calculation")
Reported-by: Andrei Vagin <avagin@xxxxxxxxxxxxx>
Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1492645870-13019-1-git-send-email-keith.busch@xxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
 kernel/irq/affinity.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index d052947..e2d356d 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -98,7 +98,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
 		int ncpus, v, vecs_to_assign, vecs_per_node;
 
 		/* Spread the vectors per node */
-		vecs_per_node = (affv - curvec) / nodes;
+		vecs_per_node = (affv - (curvec - affd->pre_vectors)) / nodes;
 
 		/* Get the cpus on this node which are in the mask */
 		cpumask_and(nmsk, cpu_online_mask, cpumask_of_node(n));